dnv-hull equipment and safety

RULES FORCLASSIFICATION OF

SHIPSNEWBUILDINGS

HULL AND EQUIPMENTMAIN CLASS

PART 3 CHAPTER 3

HULL EQUIPMENT AND SAFETYJANUARY 2003

CONTENTS PAGE

Sec. 1 General Requirements ................................................................................................................ 7Sec. 2 Sternframes, Rudders and Steering Gears ................................................................................. 8Sec. 3 Anchoring and Mooring Equipment ........................................................................................ 30Sec. 4 Masts and Rigging.................................................................................................................... 44Sec. 5 Seats for Additional Lifting, Towing or Mooring Equipment ................................................ 47Sec. 6 Openings and Closing Appliances ........................................................................................... 50Sec. 7 Corrosion Prevention................................................................................................................ 69Sec. 8 Protection of the Crew.............................................................................................................. 72Sec. 9 Intact Stability .......................................................................................................................... 74Sec. 10 Fire Safety ................................................................................................................................ 80Sec. 11 Lifesaving Arrangement........................................................................................................... 86Sec. 12 Internal Communication........................................................................................................... 90App. A Additional Requirements for non — duplicated Rudder Actuators ........................................ 93

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Veritasveien 1, N-1322 Høvik, Norway Tel.: +47 67 57 99 00 Fax: +47 67 57 99 11

CHANGES IN THE RULES

General

The present edition of the rules includes additions and amendmentsdecided by the board as of December 2002 and supersedes the January2000 edition of the same chapter (including later amendments).

The rule changes come into force 1 July 2003.

This chapter is valid until superseded by a revised chapter. Supple-ments will not be issued except for minor amendments and an updatedlist of corrections presented in Pt.0 Ch.1 Sec.3. Pt.0 Ch.1 is normallyrevised in January and July each year.

Revised chapters will be forwarded to all subscribers to the rules.Buyers of reprints are advised to check the updated list of rule chap-ters printed Pt.0 Ch.1 Sec.1 to ensure that the chapter is current.

Main changes

• Section 2 – Sternframes, Rudders and Steering Gears

— Items A301, A304 has been amended with requirements to flaprudders.

— A new item A305 has been inserted with requirements to flaprudders.

— Items A305 and A306 have been renumbered to A306 and A307.— Item J106 has been amended to account for friction losses due to

ageing.— Item K401 has been amended with respect to overbalanced rud-

ders.

• Section 3 – Anchoring and Mooring Equipment

— Item C201 has been amended with a guidance note on differencein length on anchor cables between two anchors.

— Item C205 has been amended to cover fishing vessels.— Item D101 has been amended to also cover S.H.H.P. (Super High

Holding Power) anchors.— New items D105, 106 and 107 covering S.H.H.P. anchors have

been inserted.— The last sentence in Item D202 dealing with cast and forged steel

has been deleted.— A new item D204 regarding anchor manufacturing has been in-

serted.— Items D401, 402 and 405 have been amended to cover S.H.H.P

anchors.— A new item D406 covering test requirements has been inserted.

— New items D504 and D506 have been inserted to cover S.H.H.P.anchors.

— Item D601 has been amended to cover S.H.H.P anchors.— Item E105 has been modified addressing steel wire rope and

chain cable.

• Section 6 – Openings and Closing Appliances

— This section has been moved from Pt.3 Ch.1 Sec.11 and Pt.3 Ch.2Sec.11 to Pt.3 Ch.3 Sec.6.

• Section 7 – Corrosion Prevention

— This section has been moved from Pt.3 Ch.1 Sec.14 and Pt.3 Ch.2Sec.14 to Pt.3 Ch.3 Sec.7.

• Section 8 – Protection of the Crew

— This section has been moved from Pt.3 Ch.1 Sec.10 and Pt.3Ch.2 Sec.10 to Pt.3 Ch.3 Sec.8.

• Section 9 – Intact Stability

— This section has been moved from Pt.3 Ch.4 to Pt.3 Ch.3 Sec.9.Intact and damage stability requirements have been retained,with some amendments to align with current practice.

• Section 10 – Fire Safety

— This section that has been moved from Pt.4 Ch.10 to Pt.3 Ch.3Sec.10. The scope of the class rules has been extensively re-duced, focusing on fire zones, protection of stairways and lifttrunks and escape routes.

• Section 11 – Lifesaving Arrangement

— This section has been moved from Pt.3 Ch.6 to Pt.3 Ch.3 Sec.11.The rules have been revised to focus on mustering of crew andpassengers, embarkation and launching of survival craft.

• Section 12 – Internal Communication

— This section that has been moved from Pt.4 Ch.12 Sec.2 to Pt.3Ch.3 Sec.12.

Corrections and Clarifications

In addition to the above stated rule requirements, a number of detect-ed errors, corrections and clarifications have been made in the exist-ing rule text.

Comments to the rules may be sent by e-mail to [email protected] subscription orders or information about subscription terms, please use [email protected] information about DNV and the Society's services is found at the Web site http://www.dnv.com

© Det Norske VeritasComputer Typesetting (FM+SGML) by Det Norske Veritas Printed in Norway

If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of Det Norske Veritas, then Det Norske Veritas shall pay compensation to such personfor his proved direct loss or damage. However, the compensation shall not exceed an amount equal to ten times the fee charged for the service in question, provided that the maximum compen-sation shall never exceed USD 2 million.In this provision "Det Norske Veritas" shall mean the Foundation Det Norske Veritas as well as all its subsidiaries, directors, officers, employees, agents and any other acting on behalf of DetNorske Veritas.

Rules for Ships, January 2003 Pt.3 Ch.3 Contents –

CONTENTS

SEC. 1 GENERAL REQUIREMENTS .......................... 7

A. Classification..........................................................................7A 100 Application........................................................................7

B. Definitions ..............................................................................7B 100 Symbols.............................................................................7

C. Documentation ......................................................................7C 100 General ..............................................................................7

SEC. 2 STERNFRAMES, RUDDERS AND STEERING GEARS .................................................................. 8

A. General...................................................................................8A 100 Introduction.......................................................................8A 200 Definitions.........................................................................8A 300 Documentation .................................................................9

B. Materials ..............................................................................10B 100 Plates and sections ..........................................................10B 200 Forgings and castings......................................................10B 300 Bearing materials ............................................................10B 400 Material certificates.........................................................10B 500 Heat treatment .................................................................11

C. Arrangement and Details ...................................................11C 100 Sternframes and rudders..................................................11C 200 Steering gears..................................................................12

D. Design Loads and Stress Analysis......................................12D 100 Rudder force and rudder torque, general .......................12D 200 Rudders with stepped contours .......................................12D 300 Stress analysis .................................................................13

E. Sternframes and Rudder Horns ........................................13E 100 General ............................................................................13E 200 Propeller posts.................................................................13E 300 Sole pieces ......................................................................14E 400 Rudder horns ...................................................................14

F. Rudders ................................................................................16F 100 General arrangement and details.....................................16F 200 Rudder plating.................................................................16F 300 Rudder bending ...............................................................16F 400 Web plates.......................................................................17F 500 Single plate rudders.........................................................17F 600 Mounting of rudder .........................................................17

G. Rudder Stocks and Shafts ..................................................17G 100 General ............................................................................17G 200 Rudder stock with couplings...........................................18G 300 Rudder shaft ....................................................................20G 400 Bearings and pintles .......................................................21

H. Propeller Nozzles.................................................................22H 100 General ............................................................................22H 200 Plating .............................................................................22H 300 Nozzle ring stiffness........................................................22H 400 Welding...........................................................................22H 500 Supports ..........................................................................23

I. Propeller Shaft Brackets ....................................................23I 100 General ............................................................................23I 200 Arrangement....................................................................23I 300 Struts ...............................................................................23I 400 Welding...........................................................................23I 500 Material ...........................................................................23I 600 Testing.............................................................................23

J. Steering Gears .....................................................................23J 100 Arrangement and performance........................................23J 200 Power actuating system, general requirements ...............24J 300 Piping systems, relief valve arrangements......................25J 400 Rudder actuator ...............................................................25J 500 Steering gear control and monitoring systems, general

requirements....................................................................27

J 600 Control gear for steering motors .....................................27J 700 Indications and alarms ...................................................27J 800 Power supply and distribution ........................................27J 900 Emergency power supply................................................28J 1000 Operating instructions.....................................................28J 1100 Additional requirements for oil carriers, chemical

carriers and liquefied gas carriers of 10 000 tons gross and upwards...........................................................28

K. Testing ................................................................................. 28K 100 Sternframes .....................................................................28K 200 Rudders and rudder stock connections ...........................28K 300 Steering gears..................................................................29K 400 Trials ...............................................................................29

SEC. 3 ANCHORING AND MOORING EQUIPMENT .................................................... 30

A. General ................................................................................ 30A 100 Introduction.....................................................................30A 200 Documentation................................................................30A 300 Assumptions....................................................................30

B. Structural Arrangement for Anchoring Equipment ...... 30B 100 General ...........................................................................30

C. Equipment Specification.................................................... 31C 100 Equipment number..........................................................31C 200 Equipment tables.............................................................32

D. Anchors ............................................................................... 33D 100 General ............................................................................33D 200 Materials .........................................................................33D 300 Anchor shackle................................................................34D 400 Testing.............................................................................34D 500 Additional requirements for H.H.P. and S.H.H.P.

anchors ............................................................................34D 600 Identification ...................................................................35

E. Anchor Chain Cables ........................................................ 35E 100 General ............................................................................35E 200 Materials .........................................................................35E 300 Heat treatment and material testing ...............................37E 400 Breaking test ...................................................................37E 500 Proof test .........................................................................37E 600 Tolerances .......................................................................37E 700 Identification ...................................................................38E 800 Repair of defects .............................................................38

F. Windlass and Chain Stoppers .......................................... 40F 100 General design ................................................................40F 200 Materials .........................................................................40F 300 Testing.............................................................................41

G. Towlines and Mooring Lines ............................................ 41G 100 General ............................................................................41G 200 Materials .........................................................................41G 300 Testing of steel wire ropes ..............................................41G 400 Testing of natural fibre ropes..........................................42G 500 Mooring Winches............................................................43

SEC. 4 MASTS AND RIGGING................................... 44

A. General ................................................................................ 44A 100 Introduction.....................................................................44A 200 Assumptions....................................................................44A 300 Definitions.......................................................................44A 400 Documentation................................................................44

B. Materials and Welding ...................................................... 44B 100 Materials .........................................................................44B 200 Welding...........................................................................45

C. Arrangement and Support ................................................ 45C 100 Masts and posts ...............................................................45C 200 Standing rigging..............................................................45

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Rules for Ships, January 2003Pt.3 Ch.3 Contents –

D. Design and Scantlings......................................................... 45D 100 General ............................................................................45D 200 Unstayed masts and posts with derricks .........................45D 300 Stayed masts or posts with derricks with a lifting

capacity not exceeding 10 t .............................................45D 400 Stayed masts of posts with derricks with a lifting

capacity of 10 t or more, but not exceeding 40 t.............45D 500 Stayed masts without derricks.........................................46D 600 Shrouds............................................................................46

SEC. 5 SEATS FOR ADDITIONAL LIFTING, TOWING OR MOORING EQUIPMENT ...... 47

A. Crane Pedestals and Miscellaneous Lifting Posts............ 47A 100 Introduction ....................................................................47A 200 Documentation ................................................................47A 300 Materials and welding .....................................................47A 400 Arrangement....................................................................47A 500 Design loads ....................................................................47A 600 Allowable stresses...........................................................48

B. Seatings for Winches, Windlasses and other Pulling Accessories........................................................................... 48

B 100 Introduction. ....................................................................48B 200 Documentation ................................................................48B 300 Design loads ....................................................................49B 400 Calculation of stresses.....................................................49B 500 Allowable stresses. Materials..........................................49

SEC. 6 OPENINGS AND CLOSING APPLIANCES . 50

A. General ................................................................................ 50A 100 Application......................................................................50A 200 Definitions.......................................................................50A 300 Documentation ................................................................50A 400 Testing.............................................................................51

B. Access Openings in Superstructures and Freeboard Deck...................................................................................... 51

B 100 Doors ...............................................................................51B 200 Sill heights.......................................................................51B 300 Access openings in freeboard and superstructure decks .52

C. Side and Stern Doors.......................................................... 52C 100 General. ...........................................................................52C 200 Structural arrangement....................................................52C 300 Design loads ....................................................................53C 400 Plating .............................................................................53C 500 Stiffeners .........................................................................53C 600 Girders.............................................................................53C 700 Closing arrangement, general .........................................54C 800 Closing arrangement, strength ........................................54C 900 Closing arrangement, system for operation and

indication/monitoring......................................................54

D. Hatchway Coamings........................................................... 55D 100 General ............................................................................55D 200 Coaming heights .............................................................55D 300 Scantlings ........................................................................55

E. Hatch Covers....................................................................... 55E 100 General ............................................................................55E 200 Design loads ....................................................................56E 300 Plating .............................................................................57E 400 Stiffeners .........................................................................57E 500 Girders.............................................................................58E 600 Stiffness of cover edges ..................................................58E 700 Structural analysis ...........................................................58

F. Hatchway Tightness Arrangement and Closing Devices 59F 100 General ............................................................................59F 200 Design and tightness requirements .................................59F 300 Securing devices in general.............................................60F 400 Securing arrangement for weathertight hatch covers......60F 500 Securing arrangement for deep tank or cargo oil

tank hatch covers.............................................................60F 600 Securing arrangement for hatch covers carrying

deck cargo .......................................................................60F 700 Drainage arrangement .....................................................61

G. Internal Doors and Hatches for Watertight Integrity.....61G 100 General ............................................................................61G 200 Operation.........................................................................61G 300 Strength ...........................................................................61

H. Ventilators ...........................................................................62H 100 Coamings and closing arrangements...............................62H 200 Thickness of coamings....................................................62H 300 Arrangement and support................................................62

I. Tank Access, Ullage and Ventilation Openings ...............62I 100 General ............................................................................62I 200 Hatchways.......................................................................62I 300 Air Pipes..........................................................................62

J. Machinery Space Openings ...............................................63J 100 Openings .........................................................................63

K. Scuppers, Inlets and Discharges........................................63K 100 Inlets and discharges .......................................................63K 200 Pipe thickness..................................................................65K 300 Scuppers ..........................................................................65K 400 Periodically unmanned machinery space........................65

L. Side Scuttles, Windows and Skylights ..............................65L 100 Side Scuttles, Windows and Skylights............................65L 200 Glass dimensions, side scuttles and windows.................66

M. Freeing Ports .......................................................................67M 100 Definitions.......................................................................67M 200 Freeing port area .............................................................67M 300 Location and protection of openings...............................67M 400 Multiple wells .................................................................67M 500 Free flow area..................................................................67M 600 Type «A», «B-100» and «B-60» ships............................68

N. Special Requirements for Type A Ships ...........................68N 100 Machinery casings...........................................................68N 200 Gangway and access .......................................................68N 300 Hatchways.......................................................................68N 400 Freeing arrangements......................................................68

SEC. 7 CORROSION PREVENTION ......................... 69

A. General.................................................................................69A 100 Definitions.......................................................................69A 200 Documentation ................................................................69

B. Corrosion prevention systems ...........................................70B 100 General ............................................................................70B 200 Coatings ..........................................................................70B 300 Cathodic protection .........................................................71

SEC. 8 PROTECTION OF THE CREW ..................... 72

A. Protection of the Crew........................................................72A 100 Guard rails.......................................................................72A 200 Gangways, walkways and passageways .........................72

SEC. 9 INTACT STABILITY ....................................... 74

A. Application, Definitions and Document Requirements...74A 100 Application......................................................................74A 200 Terms ..............................................................................74A 300 Documentation for approval ...........................................74

B. Surveys and Tests ..............................................................74B 100 General ............................................................................74

C. General Requirements........................................................75C 100 Stability book ..................................................................75C 200 Fixed Ballast ...................................................................75C 300 Draught Marks ................................................................75C 400 Loading Computer System..............................................75

D. Intact Stability Criteria .....................................................75D 100 General stability criteria..................................................75D 200 Weather criterion.............................................................76D 300 Assumptions concerning intact stability criteria and

calculations......................................................................78

DET NORSKE VERITAS

Rules for Ships, January 2003 Pt.3 Ch.3 Contents –

E. Damage Stability .................................................................78E 100 Damage stability .............................................................78

F. Determination of Lightweight Data...................................78F 100 Application......................................................................78F 200 Procedure ........................................................................78F 300 Lightweight Survey.........................................................79

SEC. 10 FIRE SAFETY.................................................... 80

A. Scope.....................................................................................80A 100 General ............................................................................80

B. Classification........................................................................80B 100 Application......................................................................80B 200 Rule references................................................................80

C. Definitions ............................................................................80C 100 Definitions.......................................................................80

D. Documentation ....................................................................83D 100 Plans and particulars .......................................................83

E. Protection of Stairways and Lift Trunks ..........................83E 100 Protection of stairways and lift trunks in

accommodation spaces, service spaces and control stations ............................................................................83

F. Means of Escape ..................................................................83F 100 Purpose............................................................................83F 200 General ............................................................................83F 300 Means of escape from accommodation spaces, service

spaces and control stations..............................................83F 400 Means of escape from machinery spaces........................84F 500 Means of escape from ro-ro spaces.................................84

G. Fire Control Plans...............................................................84G 100 Fire Control Plans ...........................................................84

H. Fire Safety Measures for Cargo Ships less than 500 Gross Tonnage................................................................................84

H 100 Application......................................................................84H 200 Documentation ................................................................84H 300 Fire pumps ......................................................................84H 400 Water distribution system ...............................................85H 500 Portable fire extinguishers ..............................................85H 600 Non-portable fire extinguishers ......................................85H 700 Fire-fighter's outfit ..........................................................85

SEC. 11 LIFESAVING ARRANGEMENT.................... 86

A. Classification........................................................................86A 100 Application......................................................................86

B. Documentation ....................................................................86B 100 Plans and particulars .......................................................86

C. Survival Craft Muster and Embarkation Arrangements ......................................................................86

C 100 (SOLAS Regulation III/11).............................................86

D. Launching Stations .............................................................86D 100 (SOLAS Reg. III/12).......................................................86

E. Stowage of Survival Craft .................................................87E 100 (SOLAS Reg. III/13).......................................................87

F. Stowage of Rescue Boats.....................................................87F 100 (SOLAS Reg. III/14).......................................................87

G. Stowage of Marine Evacuation Systems .......................... 87G 100 (SOLAS Reg. III/15).......................................................87

H. Survival Craft Launching and Recovery Arrangements 87H 100 (SOLAS Reg. III/16).......................................................87

I. Rescue Boat Embarkation, Launching and Recovery Arrangement....................................................................... 88

I 100 (SOLAS Reg. III/17).......................................................88

J. Survival Craft and Rescue Boats ...................................... 88J 100 (SOLAS Reg. III/31).......................................................88

K. Survival Craft Embarkation and Launching Arrangements ..................................................................... 89

K 100 (SOLAS Reg. III/33).......................................................89

SEC. 12 INTERNAL COMMUNICATION................... 90

A. General Requirements ....................................................... 90A 100 Application......................................................................90A 200 Classification...................................................................90A 300 Design documentation ....................................................90A 400 ATOS or certification at the manufacturer .....................90A 500 Onboard survey or functional testing..............................90A 600 Terms, definitions and abbreviations ..............................90

B. Ship Requirements - Main Class ...................................... 90B 100 Two way voice communication ......................................90B 200 Public address system/General alarm .............................91B 300 Electrical requirements ...................................................91

C. Ship Requirements - Additional Class ............................. 91C 100 Fishing vessels ................................................................91C 200 Oil production and storage vessels .................................91C 300 Periodically unattended machinery space.......................92C 400 Dynamic positioning systems .........................................92C 500 Nautical safety ................................................................92

APP. A ADDITIONAL REQUIREMENTS FOR NON — DUPLICATED RUDDER ACTUATORS ...... 93

A. Introduction ........................................................................ 93A 100 Scope...............................................................................93

B. Materials ............................................................................. 93B 100 Special Requirements......................................................93

C. Design .................................................................................. 93C 100 Design pressure ...............................................................93C 200 Analysis...........................................................................93C 300 Dynamic loads for fatigue and fracture mechanics

analysis............................................................................93C 400 Allowable stresses...........................................................93C 500 Burst test .........................................................................93

D. Construction Details........................................................... 93D 100 General ............................................................................93D 200 Welds ..............................................................................93D 300 Oil seals...........................................................................93D 400 Isolating valves ...............................................................93D 500 Relief valves....................................................................94

E. Testing ................................................................................. 94E 100 Non-destructive testing ...................................................94E 200 Other testing....................................................................94

DET NORSKE VERITAS

Rules for Ships, January 2003Pt.3 Ch.3 Contents –

DET NORSKE VERITAS

Rules for Ships, January 2003 Pt.3 Ch.3 Sec.1 –

SECTION 1GENERAL REQUIREMENTS

A. Classification

A 100 Application101 The Rules in this chapter apply to steering arrangementand anchoring, mooring and load handling equipment.

102 Necessary strengthening of the hull structure due toloads imposed by the equipment and installations are givenwhere appropriate.

B. Definitions

B 100 Symbols101

L = Rule length in m 1)

B = Rule breadth in m 1)

D = Rule depth in m 1)

T = Rule draught in m 1)

∆ = Rule displacement in t 1)

CB = Rule block coefficient 1)

V = maximum service speed in knots on draught T

1) For details see Ch.1 Sec.1 B

C. Documentation

C 100 General

101 Plans and particulars to be submitted for approval or in-formation are specified in the respective sections of this chap-ter.

102 For instrumentation and automation, including compu-ter based control and monitoring, see Pt.4 Ch.9 Sec.1.

DET NORSKE VERITAS

Rules for Ships, January 2003Pt.3 Ch.3 Sec.2 –

SECTION 2STERNFRAMES, RUDDERS AND STEERING GEARS

A. General

A 100 Introduction101 Requirements to side thrusters and other appliances in-tended for manoeuvring or positioning purposes are given inPt.4 Ch.5.

A 200 Definitions201 Main steering gear means the machinery, rudder actua-tor(s), the steering gear power units, if any, and ancillaryequipment and the means of applying torque to the rudderstock (e.g. tiller or quadrant) necessary for effecting movementof the rudder for the purpose of steering the ship under normalservice conditions.

202 Auxiliary steering gear means the equipment other thanany part of the main steering gear necessary to steer the ship inthe event of failure of the main steering gear but not includingthe tiller, quadrant or components serving the same purpose.

203 Steering gear control system means the equipment bywhich orders are transmitted from the navigating bridge to thesteering gear power units. Steering gear control systems com-prise transmitters, receivers, hydraulic control pumps and theirassociated motors, motor controllers, piping and cables.

204 Rudder actuator means the component which convertsdirectly hydraulic pressure into mechanical action to move therudder.

205 Steering gear power unit means:

1) in the case of electric steering gear, an electric motor andits associated electrical equipment;

2) in the case of electrohydraulic steering gear, an electricmotor and its associated electrical equipment and connect-ed pump;

3) in the case of other hydraulic steering gear, a driving en-gine and connected pump.

206 Power actuating system means the hydraulic equipmentprovided for supplying power to turn the rudder stock, com-prising a steering gear power unit or units, together with the as-sociated pipes and fittings, and a rudder actuator. The poweractuating systems may share common mechanical compo-nents, i.e. tiller quadrant and rudder stock, or components serv-ing the same purpose.

207 Maximum ahead service speed is the maximum speedcorresponding to maximum nominal shaft RPM and corre-sponding engine MCR in service at sea on summer load water-line.

208 Maximum astern speed is the speed which it is estimatedthe ship can attain at the designed maximum astern power atthe deepest seagoing draught.

209 Maximum working pressure means the maximum oilpressure in the system when the steering gear is operated tocomply with J102.

210 For terms redundancy and independence see Pt.4 Ch.1Sec.1.

211 Some terms used for rudder, rudder stock and supportingstructure are shown in Fig. 1.

DET NORSKE VERITAS


Fig. 1Rudders

212 Symbols:

f1 = material factor, see Bpm = maximum bearing surface pressure, see BFR = design rudder force, see DMTR= design rudder torque, see DA = total area in m2 of rudder bladeH = mean rudder height in m.

A 300 Documentation

301 Plans etc. as specified below are to be submitted for ap-proval:

— sternframe, horn and propeller brackets, outline of the pro-peller

— rudder including details of bearings, shaft, pintles and rud-der lock arrangement

— rudder stock including details of couplings, bolts and keys— rudder carrier— sectional drawing of rudder actuator— dimension drawings for torque transmitting parts and parts

subject to internal hydraulic pressure— foundation bolts and chocks— rudder stoppers— piping (and function) diagram according to Pt.4 Ch.6— schematic diagrams for:

— power supply arrangement— motor control systems (detailed requirements for the

diagrams are given in Pt.4 Ch.8 for electrical installa-tions)

— calculations according to K402 and K403 if sea trials areplanned to be carried out in a load condition not providingfully submerged rudder. Such calculations are at least toinclude evaluation of expected trial loads (torque and sup-port reaction forces) on the actuator versus calculated rud-der torque fully submerged and at trial conditions taking

into account the friction losses and any back pressure inthe return side

— for flap rudders and others of non-conventional design:calculation of required torque for sea trial condition (acondition with new effectively lubricated bearing bush-ings) and for normal operational condition (old worn bear-ing bushings).

The plans are to give full details of scantlings and arrangementas well as data necessary for verifying scantling calculationstogether with proposed rated torque. Set pressure for all reliefvalves are to be specified. Material specifications and particu-lars about heat treatment are also required.

302 For important components of welded construction (e.g.rudder, rudder stock, tiller), full details of the joints, weldingprocedure, filler metal and heat treatment after welding are tobe specified on the plans.

303 Procedure for stress relieving of nodular cast iron andcast steel parts, when dimensional stability is important (suchas tiller and rotor, see B502), is to be specified on the plans.

304 Plans of the following items are to be submitted for in-formation:

— general arrangement drawings of steering gear and steer-ing gear compartment

— installation instructions for steering gear (inclusive fittingto rudder stock)

— locking or brake arrangement— steering gear relief valve discharge characteristics (pres-

sure-flow diagram)— total delivery capacity of steering gear hydraulic pumps— operation instructions (according to J1000)— for flap rudders and others of non-conventional design:

torque characteristics (torque versus rudder angle).Guidance note:For the last item it is sufficient to have hydrodynamic torque ver-sus rudder angle documented in homogeneous water stream.

---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---

305 For flap rudders, an instruction manual for mounting,

DET NORSKE VERITAS


dismounting and maintenance shall be submitted for informa-tion. In addition to information considered relevant by themanufacturer, such a manual shall contain at least the follow-ing:

— mounting and dismounting procedure (including the flapas a detached component)

— mounting and dismounting procedures and allowableclearances of bushings for the rudder stock, pintles andflap pins

— measuring procedure of bearing clearances afloat and indock

— bearing lubrication system (as relevant).

A copy of the manual shall be made available onboard. Thismanual may be requested for other rudder types considered be-ing of a non-conventional design.

306 Steering gear manufacturers who intend their product tocomply with the requirements of the IMO Guidelines for non-duplicated rudder actuators, see Appendix A, are to submitdocumentation as specified in the guidelines when plans areforwarded for approval.


B. Materials

B 100 Plates and sections101 Selection of material grades for plates and sections is tobe based on material thickness. NV-steel grades as given in Ta-ble B1 will normally be accepted.

102 The material factor f1 included in the various formulaefor structures may be taken as:

f1 = 1.0 for NV-NS steel

f1 = 1.08 for NV-27 steel




B 200 Forgings and castings201 Rudder stocks, pintles, coupling bolts, keys and castparts of rudders are to be made of rolled, forged or cast carbonmanganese steel in accordance with Pt.2.

For rudder stocks, pintles, keys and bolts the minimum yieldstress is not to be less than 200 N/mm2.

202 Nodular cast iron may be accepted in certain parts afterspecial considerations. Materials with minimum specified ten-sile strength lower than 400 N/mm2 or higher than 900 N/mm2

will normally not be accepted in rudder stocks, axle or pintles,keys and bolts.

203 Ram cylinders, pressure housings of rotary vane type ac-tuators, hydraulic power piping, valves, flanges and fittings,and all steering gear components transmitting mechanical forc-es to the rudder stock (such as tillers, quadrants, or similarcomponents) are to be of steel or other approved ductile mate-rial, duly tested in accordance with the requirements of Pt.2. Ingeneral, such material is to have an elongation of not less than12 % nor a tensile strength in excess of 650 N/mm2.

Grey cast iron may be accepted for redundant parts with lowstress level, excluding cylinders, upon special consideration.

204 The material factor f1 for forgings (including rolledround bars) and castings may be taken as:

σf = minimum upper yield stress in N/mm2, not to be takengreater than 70% of the ultimate tensile strength. If notspecified on the drawings, σf is taken as 50% of the ul-timate tensile strength.

a = 0.75 for σ f > 235 = 1.0 for σ f < 235

205 Before significant reductions in rudder stock diameterdue to the application of steels with yield stresses exceeding235 N/mm2 are granted, the Society may require the evaluationof the rudder stock deformations. Large deformations shouldbe avoided in order to avoid excessive edge pressures in wayof bearings. The slope of the stock should be related to thebearing clearance, see G405.

B 300 Bearing materials301 Bearing materials for bushings are to be stainless steel,bronze, white metal, synthetic material or lignum vitae. Stain-less steel or bronze bushings are to be used in an approvedcombination with steel or bronze liners on the axle, pintle orstock.

The difference in hardness of bushing and liners is not to beless than 65 Brinell. 13% Chromium steel is to be avoided.

302 Synthetic bearing bushing materials are to be of an ap-proved type. For this type of bushing, adequate supply of lubri-cation to the bearing for cooling/lubrication purposes is to beprovided.

303 The maximum surface pressure pm for the various bear-ing combinations is to be taken as given in Table B2.

Surface pressure exceeding the values in Table B2 may be ac-cepted for rudder actuator bearings in accordance with bearingmanufacturer's specification and when verified by tests.

B 400 Material certificates401 «Det Norske Veritas Product Certificate» (NV) will berequired for:

— sternframe structural parts— rudder structural parts— rudder shaft or pintles— rudder stock— rudder carrier— tiller or rotor— crosshead— cylinders/rams— rotor housing— manifolds.

Table B1 Plate material gradesThickness in mm Normal strength

structural steelHigh strength struc-

tural steelt ≤ 30 A A

30 < t ≤ 40 B A40 < t ≤ 120 D D Table B2 Bearing surface pressures

Bearing material pm (kN/m2)Lignum vitae 2500White metal, oil lubricated 4500Synthetic material with hardness between 60 and 70 Shore D 5500 2)

Steel 1) and bronze and hot-pressed bronze-graphite materials 7000

1) Stainless and wear-resistant steel in an approved combination with stock liner

2) Surface pressure exceeding the specified limit may be accepted for rud-der bearing applications in accordance with bearing manufacturer's specification and when verified by tests and/or service experience.

f1

σ f

235---------

a=

DET NORSKE VERITAS


402 “Works certificate” (W) will be accepted for:

— bolts and pins— stoppers— steering gear covers— steering gear pistons.

B 500 Heat treatment

501 Fabricated parts in the steering gear are to be fully an-nealed after welding.

502 Nodular cast iron and cast steel parts for transmission ofrudder torque by means of keyless conical or cylindrical con-nections are to be stress relieved.

C. Arrangement and Details

C 100 Sternframes and rudders

101 Relevant types of rudder arrangements are shown in Fig.1. Other combinations of couplings and bearings may be ap-plied.

102 Suitable arrangement to prevent the rudder from liftingand accidental unshipping is to be provided. The arrangementis to effectively limit vertical movement of rudder in case ofextreme (accidental) vertical load on rudder.

103 Effective means are to be provided for supporting theweight of the rudder without excessive bearing pressure, e.g.by a rudder carrier attached to the upper part of the rudderstock. The hull structure in way of the rudder carrier is to besuitably strengthened.

104 If the rudder trunk is open to the sea, a seal or stuffingbox is to be fitted above the deepest load waterline, to preventwater from entering the steering gear compartment and the lu-bricant from being washed away from the rudder carrier.

An additional seal of approved type is required when the rud-der carrier is below the summer load waterline.

105

Guidance note:

The after body should be so shaped as to ensure a proper flow ofwater to the propeller, and so as to prevent uneven formation ofeddies as far as possible. The apex of the waterlines in front ofthe propeller should have the least possible radius, together witha relatively small angle φ. Plane or approximately plane partsabove the propeller tip should be avoided.

The strength of pressure impulses from propeller to hull will nor-mally decrease with increasing clearances. However, even withlarge clearances to the propeller, a hull may be exposed to strongimpulses if the propeller is subject to heavy cavitation.

For a moderately cavitating propeller, the following minimumclearances are proposed (see Table C1 and Fig. 2):

R = propeller radius in mZP = number of propeller blades.


Fig. 2Propeller clearances

106 Guidance note:Rudders (one or more) working directly behind a propellershould preferably have a total area not less than:

For ships which frequently manoeuvre in harbours, canals or oth-er narrow waters, the rudder area determined by the formulashould be increased. For ships with a streamlined rudder post,half of the lateral area of the post may be included in the rudderarea. For ships with a rudder horn, the whole area of the horn lay-ing below a horizontal line from the top of the rudder may be in-cluded.Rudders not working directly behind a propeller should have thearea as given above, increased by at least 30%.Rudders with special profiles or special configurations (e.g. flapsor nozzles) giving increased efficiency may have smaller total ar-eas.For ships with large freeboard and/or high continuous super-structures an increase of the rudder area ought to be considered.Larger rudder area may result in excessive heeling angle whenusing the rudder in extreme position at full speed ahead. This isparticularly relevant for passenger vessels, ferries, vehicle ro/rocarriers and other vessels where the combination of speed,draught, vertical centre of gravity and metacentric height may re-sult in excessive heeling angle in case of smaller turning circles.For estimating the result angle of heel, reference is made to Pt.5Ch.2 Sec.2 F300.In cases where the resulting angle of heel may exceed 10 degrees,the Master should be provided with warning about this in the sta-bility manual.


107 Guidance note:In order to minimise vibrations, the balancing and design of therudders should be carried out as follows:

- the balanced portion should not be greater than 23% of the to-tal area of the rudder

- the length of the balanced part at any horizontal sectionshould nowhere be greater than 35% of the total length of therudder

- the widest part of the rudder section should preferably be atleast 30% aft of the leading edge of the rudder section consid-ered.


108 Over-balanced rudders are subject to special considera-tion with respect to type of steering gear and risk of an unex-

Table C1 Minimum clearancesFor single screw ships: For twin screw ships:a ≥ 0.2 R (m)b ≥ (0.7 – 0.04 ZP) R (m)c ≥ (0.48 – 0.02 ZP) R (m) c ≥ (0.6 – 0.02 ZP) R (m)e ≥ 0.07 R (m)

ATL100--------- 1 50CB

2 BL----

2+ (m

2 )=

DET NORSKE VERITAS


pected and uncontrolled sudden large movement of ruddercausing severe change of ship's pre-set course. See J106.

Guidance note:A rudder shall be considered over-balanced, when balanced por-tion exceed 30% in any actual load condition. Special ruddertypes, such as flap rudders, are subject to special consideration.


C 200 Steering gears

201 For arrangement and details of steering gear see subsec-tion J.

D. Design Loads and Stress Analysis

D 100 Rudder force and rudder torque, general

101 The rudder force upon which the rudder scantlings are tobe based is to be determined from the following formula:

FR = 0.044 k1 k2 k3 A V2 (kN)

A = area of rudder blade in m2, including area of flap. = vertical projected area of nozzle rudderk1 = coefficient depending on rudder profile type (see Fig.

3):

k2 = coefficient depending on rudder/nozzle arrangement = 1.0 in general = 0.8 for rudders which at no angle of helm work in the

propeller slip stream = 1.15 for rudders behind a fixed propeller nozzle

k3 = not to be taken greater than 4

H = mean height in m of the rudder area. Mean height andmean breadth B of rudder area to be calculated asshown in Fig. 4

At = total area of rudder blade in m2 including area of flapand area of rudder post or rudder horn, if any, withinthe height H.

V = maximum service speed (knots) with the ship on sum-mer load waterline. When the speed is less than 10knots, V is to be replaced by the expression:

For the astern condition the maximum astern speed is to beused, however, in no case less than:

Vastern = 0.5 V

The maximum service speed corresponds to the maximumcontinuous rating (MCR) of the engine. In special ship types(such as tugs) the maximum output of the propelling machin-ery may exceed MCR by more than 15%. In such cases V is to

be increased by the following percentage:

102 The rule rudder torque is to be calculated for both theahead and astern condition according to the formula:

MTR = FR xe (kNm)

= minimum 0.1 FR B

FR = as given in 101 for ahead and astern conditionsxe = B (α - k) (m)B = mean breadth of rudder area, see Fig. 4α = 0.33 for ahead condition = 0.66 for astern condition

k =

AF = area in m2 of the portion of the rudder blade area situ-ated ahead of the center line of the rudder stock

A = rudder blade area as given in 101.

For special rudder designs (such as flap rudders) direct calcu-lations of rudder torque, supported by measurements on simi-lar rudders, may be considered as basis for rudder torqueestimation.

Fig. 3Rudder profiles

D 200 Rudders with stepped contours201 The total rudder force FR is to be calculated according to101, with height and area taken for the whole rudder.

202 The pressure distribution over the rudder area may bedetermined by dividing the rudder into relevant rectangular ortrapezoidal areas, see e.g. Fig. 5. The rule rudder torque maybe determined by:

= minimum 0.1 FR xem

n = number of parts

Table D1 Rudder profile type - coefficientProfile type Ahead AsternNACA - Göttingen 1.1 0.8Hollow profile 1) 1.35 0.9Flatsided 1.1 0.9Profile with «fish tail» 1.4 0.8Rudder with flap 1.65 1.3Nozzle rudder 1.9 1.51) Profile where the width somewhere along the length is 75% or less of

the width of a flat side profile with same nose radius and a straight line tangent to after end

H2

At------ 2+

VminV 20+

3----------------=

Table D2 Percentage increase in MCR vs VMaximum engine output above normal (%) 15 20 25 30 35 40

V increase (%) 3 5 7 9 11 12

AF

A-------

MTR FRixei( ) (kNm)

i 1=

n

∑=

DET NORSKE VERITAS


i = integer

F Ri =

x ei = Bi (α - ki)

x em =

Ai = partial area in m2

Bi = mean breadth of part area, see Fig. 4α = as given in 102

For parts of a rudder behind a fixed structure such as arudder horn:

α = 0.25 for ahead condition

= 0.55 for astern condition

ki =

A iF = rudder part area forward of rudder stock centre line,see Fig. 5

FR and A as given in 102.

Fig. 4Rudder dimensions

Fig. 5Rudder area distribution

D 300 Stress analysis

301 The rudder force and resulting rudder torque as given in100 and 200, causes bending moments and shear forces in therudder body, bending moments and torques in the rudder stock,supporting forces in pintle bearings and rudder stock bearingsand bending moments, shear forces and torques in rudderhorns and heel pieces.

The bending moments, shear forces and torques as well as thereaction forces are to be determined by a direct calculation orby approximate simplified formulae as given in the following.

For rudders supported by sole pieces or rudder horns thesestructures are to be included in the calculation model in orderto account for the elastic support of the rudder body.

Acceptable direct calculation methods are given in Classifica-tion Note No. 32.1 “Strength Analysis of Rudder Arrange-ments”. For rudder horns, see also E404.

302 Allowable stresses for the various strength members aregiven in subsections E to J.

For evaluation of angular deflections, see B205 and G405.

E. Sternframes and Rudder Horns

E 100 General

101 Sternframes and rudder horns are to be effectively at-tached to the surrounding hull structures. In particular the sternbearing or vertical coupling flange for rudder axle is to be ap-propriately attached to the transom floor adjacent to the rudderstock.

For semi-spade and spade rudder arrangements structural con-tinuity in the transverse as well as the longitudinal direction isto be specially observed.

102 Cast steel sternframes and welded sternframes are to bestrengthened by transverse webs.

Castings are to be of simple design, and sudden changes of sec-tion are to be avoided. Where shell plating, floors or otherstructural parts are welded to the sternframe, there is to be agradual thickness reduction towards the joint.

Steel forgings and castings for sternframes, rudder horns andrudders are to be in accordance with the requirements in Pt.2Ch.2 Sec.5 and Sec.7 for general applications.

103 Depending on casting facilities, larger cast steel propel-ler posts are to be made in two or more pieces. Sufficientstrength is to be maintained at connections. The plates of weld-ed propeller posts may be welded to a suitable steel bar at theafter end of the propeller post.

104 Stresses determined by direct calculations as indicatedin D300 are normally not to exceed the following values:

— Normal stress : σ = 80 f1 (N/mm2)— Shear stress : τ = 50 f1 (N/mm2)— Equivalent stress : σ e = 120 f1 (N/mm2)

E 200 Propeller posts

201 The boss thickness at the bore for the stern tube is not tobe less than:

dp = rule diameter of propeller shaft in mm.

202 The scantlings of fabricated propeller posts are not to be

Ai

A-----FR

AiBi( )A

----------------

i 1=

n

∑

AiF

Ai--------

σe σ12 σ2

2 σ1σ2– 3τ2+ +=

t 5 dp 60– (mm)=

DET NORSKE VERITAS


less than:

l, b and t are as shown in Fig. 6 Alt. I.

Where the section adopted differs from the above, the sectionmodulus about the longitudinal axis is not to be less than:

203 The scantlings of cast steel propeller posts are not to beless than:

l, b, t1 and t2 are as shown in Fig. 6 Alt. II.

Where the section adopted differs from the above, the sectionmodulus about the longitudinal axis is not to be less than:

When calculating the section modulus, adjoining shell plateswithin a width equal to 53 from the after end of the postmay be included.

Fig. 6Propeller posts

E 300 Sole pieces301 The sole piece is to be sloped in order to avoid pressurefrom keel blocks when docking. The sole piece is to extend atleast two frame spaces forward of forward edge of the propel-

ler boss. The cross section of this extended part may be gradu-ally reduced to the cross section necessary for an efficientconnection to the plate keel.

302 The section modulus requirement of the sole piece abouta vertical axis abaft the forward edge of the propeller post isgiven by:

ls = distance in m from the centre line of the rudder stockto the section in question. ls is not to be taken less thanhalf the free length of the sole piece.

303 The section modulus of the sole piece about a horizontalaxis abaft the forward edge of the propeller post is in no placeto be less than:

304 The sectional area of the sole piece is not to be less than:

E 400 Rudder horns401 The section modulus requirement of the rudder hornabout a longitudinal axis is given by:

lh = vertical distance in m from the middle of the horn pin-tle bearing to the section in question

yh = vertical distance in m from the middle of the rule pintlebearing to the middle of the neck bearing

F Ri = part of rudder force acting on the i-th part of the rudderarea, see D202

y ei = vertical distance in m from the centroid of the i-th partof the rudder area to the middle of the neck bearing

n = number of rudder parts

For the straight part of the rudder horn the section modulusmay be taken for the total sectional area of the horn.

When the connection between the rudder horn and the hullstructure is designed as a curved transition into the hull platingthe section modulus requirement as given above is to be satis-fied by the transverse web plates as follows:

n = number of transverse websbi = effective breadth in mm of web no. i. (including the

flange thickness)ti = thickness in mm of web no. ibmax = largest bi.

Z, bi and bmax are to be taken at a horizontal section 0.7 r abovethe point where the curved transition starts (r = radius ofcurved part, see Fig. 7).

The formula for ZW is based on the material in web plates andshell plate being of the same strength.

l 53 L (mm)=

b 37 L (mm)=

t2.4 L

f1

---------------- (mm)=

ZW1.35L L

f1----------------------- (cm

3 )=

l 40 L (mm)=

b 30 L (mm)=

t13 L

f1

----------- (mm)=

t23.7 L

f1

---------------- (mm)=

ZC1.3L L

f1-------------------- (cm

3 )=

L

Z1

6.25FRls

f1---------------------- (cm

3 )=

Z2

Z1

2------ (cm

3 )=

AS

0.1FR

f1--------------- (cm

2 )=

Z15MVlh

yhf1-------------------- (cm

3 )=

MV FRiyei

i 1=

n

∑=

ZW

bi3ti

i 1=

n

∑

6000bmax------------------------ 0.45Z≥=

DET NORSKE VERITAS


For a cast rudder horn any vertical extension of the side plating(see Fig. 8) may be included in the section modulus.

Fig. 7Curved plate transition rudder horn/shell plating

Fig. 8Curved cast transition rudder horn/shell plating

402 The rudder horn thickness requirement is given by:

k =

eh = horizontal projected distance in m from the centre lineof the horn pintle to the centroid of AS

AS = area in cm2 in horizontal section enclosed by the horn.

For a curved transition between horn plating and shell platingthe thickness of the transition zone plate is not to be less than:

s = spacing between transverse webs in mmr = radius of curved transition in mmZA = section modulus at section immediately below the

transition zoneZ = section modulus requirement in same section, as given

in 401.

403 The vertical parts of the rudder horn participating in thestrength against transverse shear are to have a total area in hor-izontal section given by:

C =

= 1.0 at lower endAH = area of horn in m2. At intermediate sections AH should

be taken for part of horn below sectionA = total area of rudder in m2.

In a curved transition zone the thickness of the transverse webplates is not to be less than:

tr = 0.8 tc (mm)

tc = thickness of curved plate

In the transition zone the curved shell plate is to be welded tothe web plates by full penetration weld or by a fillet weld withthroat thickness not less than:

t = 0.55 f1 tr (mm)

404 A direct stress analysis of the rudder horn, if carried out,is to be based on a finite element method.

For a curved transition to the hull structure the maximum al-lowable normal and equivalent stresses as given in 104, may inthe curved plate be increased to:

σ = 120 f1 N/mm2

σ e = 180 f1 N/mm2

A fine-mesh finite element calculation will be considered as anacceptable method.

In the web plates the normal stresses should not exceed σ = 130 f1 N/mm2.

405 For a curved transition between the horn side plating andthe shell plating, the side plate thicknesses given in 401 to 404are to be extended to the upper tangent line of the curved part.

t110kFReh

f1AS------------------------- (mm)=

50

4000 1500 Z ZA⁄( )2–

---------------------------------------------------------

tc0.15 s 40–( )2

r--------------------------------- Z

ZA------- (mm)=

AW C0.3FR

f1--------------- (cm

2 )=

1A AH+( )AH

A2

--------------------------------+

at upper end of horn

DET NORSKE VERITAS


The transverse web thicknesses are to be kept to the same leveland are to be welded to the floors above. No notches, scallopsor other openings are to be taken in the transition area.

The alternative design is to carry the side plating of the rudderhorn through the shell plate and connect it to longitudinal gird-ers (see Fig. 9), or weld it to the shell plate in line with longi-tudinal girders. In the latter case the welds below and above theshell plate are to be full penetration welds, and the shell plateis to be specially checked for lamellar tearing. The transversegirders are to be connected to/supported by transverse floors.

Floor plating welded to rudder horn web plates is to have athickness not less than 75% of the web plate thickness.

406 The lower end of the rudder horn is to be covered by ahorizontal plate with thickness not less than the side plating.

Fig. 9Shell plating connected to longitudinal girders in line with rudderhorn sides

F. Rudders

F 100 General arrangement and details

101 Rudders are to be double plate type with internal verticaland horizontal web plates.

The rudder body is to be stiffened by horizontal and verticalwebs enabling it to act as a girder in bending.

Single plate rudders may be applied to smaller vessels of spe-cial design and with service restrictions, see 500.

102 All rudder bearings are to be accessible for measuring ofwear without lifting or unshipping the rudder.

Guidance note:In case cover plates are permanently welded to the side plating,it is recommended to arrange peep holes for inspection of secur-ing of nuts and pintles.


103 Great care is to be taken in highly stressed connectionssuch as:

— welds between rudder side plating and upper heavy part ofrudder at stock coupling

— welds around cut-outs in semi-spade rudders and openingsfor demounting of cone coupling and pintles.

104 Welds between plates and heavy pieces (cast or verythick plating) are to be made as full penetration welds, prefer-ably to cast or welded on ribs. Where back welding is impos-sible welding is to be performed against backing bar orequivalent.

105 Webs are to be connected to the side plates in accord-ance with Ch.1 Sec.12.

Slot-welding is to be limited as far as possible. Horizontal slotsin side plating in areas with large bending stresses are to becompletely filled by welding.

Normally, slots of length 75 mm and a breadth of 2 t (where t= rudder plate thickness), with a distance of 125 mm betweenends of slots, will be accepted. In areas where slots are requiredto be completely filled by welding, more narrow slots with in-clined sides (minimum 15° to the vertical) and a minimumopening of 6 mm at bottom may be used. A continuous slotweld may, however, in such cases be more practical.

106 Plate edges at corners in cut-outs and openings in rudderside plating are to be ground smooth in those parts of the rud-der where high stresses will occur.

107 Means for draining the rudder completely after pressuretesting or possible leakages is to be provided. Drain plugs areto be fitted with efficient packing.

108 Internal surfaces are to be covered by a corrosion-resist-ant coating after pressure-testing and possible stress-relieving.

109 For testing of rudder, see K.

F 200 Rudder plating201 The thickness requirement of side, top and bottom plat-ing is given by:

ka =

maximum 1.0

s = the smaller of the distances between the horizontal orthe vertical web plates in m

b = the larger of the distances between the horizontal or thevertical web plates in m.

In no case the thickness is to be less than the minimum sideplate thickness as given in Ch.1 Sec.7 C101 or Ch.2 Sec.6C102.

F 300 Rudder bending301 Bending moments in the rudder are to be determined bydirect calculations as indicated in D300.

For some common rudder types the following approximateformulae may be applied:

t5.5

f1

--------kas T0.1FR

A---------------+ 2.5 (mm)+=

1.171 0– .5sb---

2

DET NORSKE VERITAS


— For balanced rudders with heel support:Mmax = 0.125 FR H (kNm)

— For semi-spade rudders at the horn pintle:

— For spade rudders:

A1 = area in m2 of the rudder part below the cross-section inquestion

hs = vertical distance in m from the centroid of the rudderarea A1 to the section in question.

302 The nominal bending stress distribution in the ruddermay normally be determined on the basis of an effective sec-tion modulus to be estimated for side plating and web plateswithin 40% of the net length (cut-outs or openings deducted)of the rudder profile. The effective length is not to be takengreater than 2.5 ds (ds = rudder stock diameter at neck bearing)or the length of the flange coupling at the top of the rudder.

Special attention to be paid to open flange couplings on therudder. The external transverse brackets will normally have tobe supplied with heavy flanges to obtain the necessary sectionmodulus of the rudder immediately below the flange.

As an alternative the bending stress distribution in the ruddermay be determined by a finite element calculation.

303 Nominal bending stresses calculated as given in 301 and302 are not to exceed:

σ = 110 f1 N/mm2 in general = 75 f1 N/mm2 at sections in way of cut-outs (e.g. semi-

spade rudders) in the rudder.

In case of openings in side plate for access to cone coupling orpintle nut, σ = 90 f1 to be applied when the corner radius isgreater than 0.15 l ( l = length of opening), σ = 60 f1 when theradius is smaller.

F 400 Web plates401 The thickness of vertical and horizontal webs is not to beless than 70% of the thickness requirement given in 200, in nocase less than 8 mm.

402 The total web area requirement for the vertical webs isgiven by:

P =

with heel support

= for spade rudder or lower part of

semi-spade rudderh1 = height in m of the smaller of rudder parts below or

above the cross-section in questionh2 = height in m of the rudder part below the cross section

in question.

Shear stresses in web plates determined by direct stress calcu-lations are not to exceed:

τ = 50 f1 (N/mm2)

Equivalent stress is not to exceed:

σe =

= 120 f1 N/mm2 in rudder-blades without cut-outs = 100 f1 N/mm2 in rudder-blades with cut-outs.

F 500 Single plate rudders501 Mainpiece diameter

The mainpiece diameter is calculated according to G201. Forspade rudders the lower third may taper down to 0.75 timesstock diameter.

When calculating the rudder force FR as given in D101 the fac-tor k1 may be taken equal to 1.0 in ahead condition.

502 Blade thickness

The blade thickness is not to be less than:

tb = 1.5 s V + 2.5 (mm)

s = spacing of stiffening arms in metres, not to exceed 1 mV = speed in knots, see D101.

503 Arms

The thickness of the arms is not to be less than the blade thick-ness:

ta = tbThe section modulus is not to be less than:

Za = 0.5 s C12 V2 (cm3)

C1 = horizontal distance from the aft edge of the rudder tothe centre line of the rudder stock in metres.

For higher tensile steels the material factor according to B100is to be used correspondingly.

F 600 Mounting of rudder601 For rudder with continuous shaft it is to be checked thatthe rudder shaft has the right position in relation to the uppercoupling, both longitudinally and transversely, when the lowertapered part of the rudder axle bears hard at the heel. The rud-der shaft is to be securely fastened at the heel before the cou-pling bolts at the upper end are fitted.

602 Before final mounting of rudder pintles, the contact be-tween conical surfaces of pintles and their housings is to bechecked by marking with Prussian blue or by similar method.When mounting the pintles, care is to be taken to ensure thatpackings will not obstruct the contact between mating surfac-es. The pintle and its nut are to be so secured that they cannotmove relatively to each other.

G. Rudder Stocks and Shafts

G 100 General101 Stresses determined by direct calculations as indicatedin D300 are normally to give equivalent stress σe not exceed-ing 118 f1 N/mm2 and shear stress τ not exceeding 68 f1 N/mm2. The equivalent stress for axles in combined bending andtorsion may be taken as:

σ = bending stress in N/mm2

τ = torsional stress in N/mm2.

102 The requirements to diameters are applicable regardlessof liner. Both ahead and astern conditions are to be considered.

103 A rudder stock cone coupling connection without hy-

MFRA1hs

A------------------- (kNm)=

Mmax

FRA1hs

A------------------- (kNm)=

AWP

5f1------- (cm

2 )=

0.6h1

H-----–

FR for balanced rudder

h2

H-----FR

σb2

3τ2+

σe σ23τ2

+ (N/mm2 )=

DET NORSKE VERITAS


draulic arrangement for mounting and dismounting is not to beapplied for spade rudders.

104 An effective sealing is to be provided at each end of thecone coupling.

G 200 Rudder stock with couplings201 The diameter requirement is given by:

kb = 1 above the rudder carrier, except where the rudderstock is subjected to bending moment induced by therudder actuator (bearing arrangement versus rudderstock bending deflections, or actuator forces acting ontiller)

=

MB = calculated bending moment in kNm at the section inquestion.

If direct calculations of bending moment distribution are notcarried out, MB at the neck bearing or the rudder coupling maybe taken as follows:

— for balanced rudder with heel support:

— for semi-spade rudder:

— for spade rudder:

MB = FR hs (kNm)

hs = vertical distance in m from the centroid of the rudderarea to the middle of the neck bearing or the coupling.

At the bearing above neck bearing MB = 0, except as follows:

— for rotary vane type actuators with two rotor bearings,which allow only small free deflections, calculation ofbending moment influence may be required if bending de-flection in way of upper bearing exceeds two times dia-metrical bearing clearances at full rudder force FR

— for actuator force induced bending moment the greater ofthe following:

M BU = FA hA (kNm) or

M BU = PA hA (kNm)

hA = vertical distance between force and bearing cen-tre

PA = according to J404M BU = bending moment at bearing above neck bearingFA = radial force induced by actuator at design pres-

sure.

Minimum diameter of the rudder stock between the neck andthe bearing above is not to be less than if tapered with kb=1.0at the second bearing.

202 Tapered cone connections between rudder stock andrudder and steering gear are to have strength equivalent to thatrequired for rudder stock with respect to transmission of torqueand bending moments as relevant and are to comply with thefollowing:

a) Length/diameter ratio:

b) Hub/shaft diameter ratio D/ds:

c) Taper of cone:

d) Contact surface roughness in micron:

— contact area minimum 70% evenly distributed (seeK200 for control and testing)

— if oil is used for fitting, the design must enable escapeof the oil from between the mating surfaces

— the connection is to be secured by a nut which is prop-erly locked to the shaft.

e) The dimensions at the slugging nut are not to be less than(see Fig. 10):

— external thread diameter:dg = 0.65 ds

— height of nut:hn = 0.6 dg

— outer diameter of nut:

dn = 1.2 dt or dn = 1.5 dg whichever is the greater.

f) Average surface pressure pr due to shrinkage for transmis-sion of torque by means of friction is to be:

T fr = required torque to be transmitted by means of fric-tion in following couplings:

1) Keyless rudder stock connections to:— rudder: 3 MTR— steering gear: 2 Tdes ≤ T fr ≥ 2 MTR

2) Keyed rudder stock connections to:— rudder: 1.5 M TR (0.5 MTR)— steering gear: T fr ≥ TW (0.25 TW)

(figures in parentheses are subject to specialconsideration - see 203)

dm = mean diameter = 0.5 (ds + dt) (mm) l = effective cone length, which may normally be tak-

en as boss length lt, see Fig. 10, (mm)µ = maximum 0.14 for oil injection fitting = maximum 0.17 for dry fittingMTR =rule rudder torque (kNm), see D102 and D202Tdes = maximum torque corresponding to steering gear

design pressure, or safety valve opening pressure(kNm) - see J404 for calculation of Tdes

Tw = effective steering gear torque at maximum workingpressure (kNm).

ds 42kb

MTR

f1------------

13---

(mm)=

143---

MB

MTR------------

2+

16---

at arbitrary cross-section

MB

FRH

7----------- (kNm)=

MB

FRH

17----------- (kNm)=

Connection Rudder Steering gearlt/ds ≥ 1.5 ≥ 0.75

Type With key Keyless D/ds ≥ 1.5 ≥ 1.25

Type With key Keylesstaper 1:10 - 1:15 1: ≥ 15

Type of fitting Dry fitted Oil injectionroughness (RA) maximum 3.5 maximum 1.6

pr

2Tfr106

π dm2lµ

------------------- (N/mm2 )≥

DET NORSKE VERITAS


g) The surface pressure (p) used for calculation of pull-uplength is not to be taken less than:

pr ≤ pmin ≥ 1.25 pb (N/mm2)and is not to exceed:

k = 0.95 for steel forging and cast steel = 0.90 for nodular cast iron = 0.50 for keyed connections.

Variation due to different hub wall thickness is to be con-sidered.Pressure at the bigger end due to bending moment, Mb,may be taken as:

which may be reduced to zero at a distance l x = 0.5 d or0.5 l (smaller applies) as follows:

p bx = pressure due to bending moment at position xlx = distance from top of cone, see Fig. 10 (mm)dx = ditto shaft diameter at distance lx (mm)Mb = bending moment (kNm).

h) Shrinkage allowance ∆ (mm):

Ei = module of elasticity of shaft (N/mm2)Ee = module of elasticity of hub (N/mm2)νi = Poisson's ratio for shaftνe = Poisson's ratio for hubci = diameter ratio di/d at considered sectionce = diameter ratio d/D at considered sectiondi = diameter of centre bore in shaft (mm)d = shaft diameter at considered section (mm)D = outer diameter of the hub at considered section

(mm).

Minimum shrinkage allowance may be calculated basedon average diameters and the surface pressure (pmin) fromthe above equation.However, in case hub wall thickness have large variationseither longitudinally or circumferencially this equation isnot valid.Maximum shrinkage allowance is to be calculated basedon maximum permissible surface pressure (pmax, see g).

i) Pull-up length, minimum:δ min = K ( ∆ min + 2 (R Ai + RAe) 10-3 ) (mm)

δmin ≥ 2 mm for all keyless rudder - rudder stock connec-tions.

j) Pull-up length, maximum:δ max = K ( ∆ max + 2 (R Ai + RAe) 10-3 ) (mm)

δ = pull-up length (mm)K = taper of the cone = lt/(ds – dt)∆min = calculated minimum shrinkage allowance

∆max =calculated maximum shrinkage allowanceR Ai = surface roughness RA of shaft (micron)R Ae = surface roughness RA of hub (micron).

k) Necessary force for pull-up may be estimated as follows:

µ pu = average friction coefficient for pull-up (for oil in-jection (usually in the range 0.01 to 0.03).

203 Tapered key-fitted (keyed) connections are to be de-signed to transmit rudder torque in all normal operating condi-tions by means of friction in order to avoid mutual movementsbetween rudder stock and hub. The key is to be regarded as asecuring device.

For calculation of minimum and maximum pull-up length see202 i) and j).

Where it is not possible or practicable to obtain above requiredminimum pull-up, special attention is to be given to fitting ofthe key in order to ensure tight fit (no free sideways play be-tween key and key-way).

Tapered key-fitted connections are in addition to comply withfollowing:

a) Key-ways shall not be placed in areas with high bendingstresses in the rudder stock and are to be provided with suf-ficient fillet radii (r):

r ≥ 0.01 ds

b) The abutting surface area between the key and key-way inthe rudder stock and hub respectively, is not to be lessthan:

where the torque Tkey is (kNm):1.5 Tdes – Tfr ≤ Tkey ≥ 2 M TR – Tfr

based on verification of pull-up force, and1.5 Tdes – 0.7 Tfr ≤ Tkey ≥ 2 MTR – 0.7 Tfr

based on verification of pull-up distance,but not less than:

Tkey = M TR (kNm).Yield strength used for calculation of fk is not to exceedthe lowest of:

σ f,keyand

1.5 σ f, hub (for calculation of hub) or1.5 σ f, stock (for calculation of stock).

A ab = effective abutting area of the key-way in stockand hub respectively (cm2)

fk = material factor (see B204)σ f,hub = yield strength of hub material (N/mm2)σ f,key = yield strength of key material (N/mm2)σ f,stock= yield strength of stock material (N/mm2).

c) The height/width ratio of the key is to be:

h = height (thickness) of the keyb = width of the key.

Where necessary tapered connections are to be provided withsuitable means (e.g. oil grooves and bores to connect hydraulicinjection oil pump) to facilitate dismantling of the hub.

204 Connection between rudder stock and splitted type oftiller or quadrant or rotor are to comply with 202 and 203 as ap-

pmax kσf

1 ce2

–

3 ce4

+

--------------------- pb (N/mm2 )–≤

pb

3.5Mb

dml2

----------------106 (N/mm

2 )=

pbx pb18 1lx

0.5dx--------------–

(N/mm2 )=

∆ dp

Ee------

1 ce2

+

1 ce2

–----------------- ve+

p

Ei-----

1 ci2

+

1 ci2

–---------------- vi–

+=

F π dmlpr1

2K------- µpu+

10

3– (kN)≥

Aab

65Tkey

dmfk----------------- (cm

2 )≥

hb--- 0.6≤

DET NORSKE VERITAS


plicable and with the following:

— boss halves are to be joined by at least four bolts (two ineach side)

— one or two keys— cylindrical connections are to be duly secured with regard

to axial loads.

205 Tiller or rotor joined to rudder stock by means of speciallocking assemblies, or by means of tapered connection with in-termediate sleeve, which transmit torque and/or axial forces bymeans of friction alone are to comply with the following:

a)2.5 Tdes ≤ Tfr ≥ 2.5 MTR

T fr = calculated friction torque.Tdes and MTR, see 202.

b) When number of locking assemblies is less than three, anarrangement is to be provided to limit drop of the rudderand stock in case of a slip in the friction connection.

Fig. 10Cone coupling

206 Where the rudder stock is connected to the rudder byhorizontal flange coupling the following requirements are tobe complied with:

a) At least 6 coupling bolts are to be used.

b) The diameter of coupling bolts is not to be less than:

dso = rule diameter of rudder stock at coupling flange inmm as given in 201

n = number of coupling boltse = mean distance in mm from the centre of bolts to the

centre of the bolt systemf ms = material factor (f1) for rudder stockf mb = material factor (f1) for bolts.

c) Nuts are to be securely fastened by split pins or other effi-cient means.

d) If the coupling is subjected to bending stresses, the meandistance a from the centre of the bolts to the longitudinalcentre line of the coupling is not to be less than 0.6 dso.

e) The width of material outside the bolt holes is not to beless than 0.67 db.

f) The thickness of coupling flanges is not to be less than thegreater of:

db = bolt diameter, calculated for a number of bolts notexceeding 8

f mf = material factor (f1) for flange,

or

MB = bending moment in kNm at couplinga = mean distance from centre of bolts to the longitudi-

nal centre line of the coupling, in mmd = diameter as built of rudder stock for stock flange,

breadth of rudder for rudder flange, both in mmβ = factor to be taken from the following table:

Ample fillet radius is to be in accordance with recognisedstandards.

G 300 Rudder shaft301 At the lower bearing, the rudder shaft diameter is not tobe less than:

c =

l, a and b are given in Fig. 11 in m.

The diameter df below the coupling flange is to be 10% greaterthan dl. If, however, the rudder shaft is protected by a corro-sion-resistant composition above the upper bearing, df may beequal to dl.

302 The taper, nut, etc. at lower end of rudder shafts, is to betaken as for rudder stock given in 202.

303 The scantlings of the vertical coupling at the upper endof the rudder shaft are to be as required for horizontal ruddercouplings in 206, inserting the shaft dl instead of the stock di-ameter dso in the formula for bolt diameter.

db 0.62dso

3fms

nefmb------------------- (mm)=

d/a 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6β 1.8 1.5 1.25 1.0 0.8 0.6 0.45 0.35 0.25

t db

fmb

fmf-------- , minimum 0,9db (mm)=

t 70βMB

afmf------------ (mm)=

dl 39FRc l c–( )

lf1-------------------------

13---

(mm)=

a b+2

------------

DET NORSKE VERITAS


Fig. 11Rudder shaft

G 400 Bearings and pintles 401 The height of bearing surfaces is to be taken not greaterthan:

hb = 1.2 dsl (mm)

dsl = diameter in mm of rudder shaft or pintle measured onthe outside of liners.

402 The bearing surface area is not to be less than:

AB = hb dslhb and dsl = as given in 401P = calculated reaction force in kN at the bearing in

questionpm = maximum surface pressure as given in B303.

If direct calculations of reaction forces are not carried out, P atvarious bearings may be taken as given in the following (notethat values given for stern pintle or neck bearing in semi-spaderudders are minimum values):

a) For balanced rudder with heel support:

P = 0.6 FR (kN) at heel pintle bearing

P = 0.7 FR (kN) at stern pintle or neck bearing

P = 0.1 FR (kN) at upper bearing.

b) For semi-spade rudder (The horn pintle bearing is assumedto be situated not more than 0.1 H above or below the cen-troid of the rudder):P = 1.1 FR (kN) at horn pintle bearingPmin = 0.4 FR (kN) at stern pintle or 0.3 FR (kN) at neckbearingP = 0.1 FR (kN) at upper bearing.

c) For spade rudder:

(kN) at neck bearing

(kN) at upper bearing

h1 = vertical distance from the centroid of rudder area tothe middle of the neck bearing

h2 = vertical distance from the middle of the neck bear-ing to the middle of the upper bearing.

403 The diameter of pintles is not to be less than:

P = as given in 402.

404 The thickness of any bushings in rudder bearings is notto be less than:

minimum 8 mm for steel and bronze,

maker's specification for synthetic materials,

minimum 22 mm for Lignum Vitae,

other materials are to be especially considered.


The bushing is to be effectively secured to the bearing. Thethickness of bearing material outside of the bushing is not tobe less than:


405 With metal bearings the clearance on the diameter isnormally not to be less than:

0.001 db + 1.0 (mm)

db=inner diameter in mm of the bushing.

If non-metallic bearing material is applied, the bearing clear-ance is to be specially determined considering the materials'swelling and thermal expansion properties. This clearance isnot to be taken less than 1.5 mm on the bearing diameter.

For spade rudders with large bending moment and induced

ABP

Pm------- 10

6 (mm

2 )=

Ph1 h2+

h2-----------------FR=

Ph1

h2-----FR=

dp 10 Pf1---- (mm)=

tv 0.32 P (mm)=

t 2.0 Pf1---- (mm)=

DET NORSKE VERITAS


slope at the neck bearing the clearance should be related to thecalculated angular deflection over the bearing length.

Due attention should, however, be given to the manufacturer'srecommended clearance. For pressure lubricated bearings theclearance will be especially considered.

406 Pintles are to have a conical attachment to the gudgeons.The various dimensions (taper, nut, key) are to be as requiredfor rudder stock in 202 and 203 inserting the pintle diameter dpinstead of the stock diameter ds in the various formulae.

The bending moment, MB may be taken as pintle force P mul-tiplied by the height from 1/3 of height of bearing to 1/2 of thelength of cone and MTR may be taken as 0.00025 dbP.

db = inner diameter of bushing (mm).

The length of pintle housing is not to be less than the pintle di-ameter and the thickness of material outside the bushing is notto be less than 0.25 db.

An effective sealing against sea water is to be provided at bothends of the cone.

H. Propeller Nozzles

H 100 General101 The following requirements are applicable to fixed andsteering nozzles of inner diameter 4 metres or less.

Guidance note:The requirements may also be applied for the initial design ofnozzles with diameter exceeding 4 metres. In that case the scantlings and arrangement should be speciallyconsidered with respect to exciting frequencies from the propel-ler.


H 200 Plating201 The thickness of the nozzle shell plating in the propellerzone is not to be less than:

where:

N = 0.01 PS D, need not be taken greater than 100PS = maximum continuous output (kW) delivered to the

propellerD = inner diameter (m) of nozzles = distance in m between ring webs, is not to be taken less

than 0.35 metres in the formulaka = aspect ratio correction as given in F201, to be applied

when longitudinal stiffeners.

The thickness in zone I and II is not to be less than 0.7 t and inzone III not less than 0.6 t, corrected for spacing s.

The propeller zone is to be taken minimum 0.25 b (where b =length of nozzle). For steering nozzles the propeller zone is tocover the variations in propeller position.

On the outer side of the nozzle, zone II is to extend beyond theaftermost ring web.

202 The thickness of ring webs and fore and aft webs is notto be taken less than 0.6 t. They are to be increased in thicknessin way of nozzle supports.

203 If the ship is reinforced according to an ice class nota-tion, the part of the outer shell of the nozzle which is situatedwithin the ice belt is to have a plate thickness not less than cor-responding to the ice class requirement for the after part of the

ship.

Guidance note:In order to prevent corrosion and erosion of the inner surface ofthe nozzle, application of a corrosion resistant material in thepropeller zone is recommended. All but welds should be groundsmooth.

When a corrosion resistant material is used, the plate thicknessmay be reduced by 15%.


H 300 Nozzle ring stiffness

301 In order to obtain a satisfactory stiffness of the nozzlering the following requirement is to be fulfilled:

I = 2.8 k b D3 V2 (cm4)

I = moment of inertia of nozzle section about the neutralaxis parallel to centre line

k =

tm = mean thickness of nozzle inner and outer shell plating(mm), in propeller plane

b = length of nozzle, see Fig. 12, in mD = as given in 201V = maximum service speed (knots)n = number of ring webs.

Fig. 12Section through nozzle ring

302 If the ship is reinforced according to an ice class notationthe parameter V for the requirement in 301 is not to be takenless than:

V = 14, 15, 16 and 17 knots for ice class 1C, 1B, 1A and1A*, respectively.

H 400 Welding

401 The inner shell plate is to be welded to the ring webswith double continuous fillet welding.

402 The outer shell plate is as far as possible to be weldedcontinuously to the ring webs. Slot welding may be acceptedon the following conditions:

If the web spacing s ≤ 350 mm all welds to outer plating maybe slot welds. If the web spacing s > 350 mm at least two ringwebs are to be welded continuously to the outer shell. A con-tinuous weld according to Fig. 13 may be accepted.

403 Slot welds are to have a slot length l not less than 75 mmand a breadth equal to 2t (t = nozzle shell plate thickness),maximum 30 mm. More narrow slots may be applied whereslots are completely filled by welding. The distance betweenslots (from centre to centre) is not to exceed 2

l, maximum 250 mm. The slot weld throat thickness is normal-ly to be 0.7 t.

t 10 3kasNf1---- (mm)+=

28b

Dtm n 1+( )--------------------------------

DET NORSKE VERITAS


H 500 Supports

501 The nozzle is to be supported by at least two supports.The web plates and shell plates of the support structure are tobe in line with web plates in the nozzle.

Fig. 13Connection nozzle shell plate/ring web

I. Propeller Shaft Brackets

I 100 General

101 The following requirements are applicable to propellershaft brackets having two struts to support the propeller tailshaft boss. The struts may be of solid or welded type.

102 The angle between the struts is not to be less than 50 de-grees.

I 200 Arrangement

201 Solid struts are to be carried continuously through theshell plating and are to be given satisfactory support by the in-ternal ship structure.

202 Welded struts may be welded to the shell plating. Theshell plating is to be reinforced, and internal brackets in linewith strut plating are to be fitted. If the struts are built with alongitudinal centre plate, this plate is to be carried continuous-ly through the shell plating. The struts are to be well roundedat fore and aft end at the transition to the hull.

203 The propeller shaft boss is to have well rounded fore andaft brackets at the connection to the struts.

204 The strut structure inside the shell is to terminate withina compartment of limited volume to reduce the effect of flood-ing in case of damage.

I 300 Struts

301 Solid or built-up struts of propeller shaft brackets are tocomply with the following requirements:

h = 0.4 d (mm)

A = 0.4 d2 (mm2)

W = 0.12 d3 (mm3)

A = area of strut sectionW = section modulus of section. W is to be calculated with

reference to the neutral axis Y-Y as indicated on Fig.14

h = the greatest thickness of the sectiond = Propeller shaft diameter in mm.

The diameter refers to shaft made of steel with a minimumspecified tensile strength of 430 N/mm2.

Fig. 14Strut section

I 400 Welding

401 Welding between struts and hull and propeller shaft bossis to be made as full penetration welds.

402 For welded construction full details of the joints, weld-ing procedure, filler metal and heat treatment after welding areto be specified on the plans.

I 500 Material

501 Regarding material of brackets reference is made to sub-section B.

I 600 Testing

601 Ultrasonic and magnetic particle examination of thewelds is to be carried out on the brackets and at the shell pen-etrations.

J. Steering Gears

J 100 Arrangement and performance

101 Unless expressly provided otherwise, every ship shall beprovided with a main steering gear and an auxiliary steeringgear to the satisfaction of the requirements in the Rules. Themain steering gear and the auxiliary steering gear shall be soarranged that the failure of one of them will not render the oth-er one inoperative.

102 The main steering gear and rudder stock shall be:

a) of adequate strength and capable of steering the ship atmaximum ahead service speed which shall be demonstrat-ed

b) capable of putting the rudder over from 35° on one side to35° on the other side with the ship at its deepest seagoingdraught and running ahead at maximum ahead servicespeed and, under the same conditions, from 35° on eitherside to 30° on the other side in not more than 28 seconds(20 seconds for class notation Tug or Supply Vessel,see Pt.5 Ch.7 Sec.2 and Sec.3 and ice classes: ICE 05-15,POLAR 10-30 and 15 seconds for Icebreaker, see Pt.5Ch.1 Sec.4)

c) operated by power where necessary to meet the require-ments in b) and in any case when the rules require a rudderstock of over 120 mm diameter in way of the tiller, exclud-ing strengthening for navigation in ice

d) so designed that they will not be damaged at maximumastern speed.

103 The auxiliary steering gear shall be:

a) of adequate strength and capable of steering the ship atnavigable speed and of being brought speedily into actionin an emergency

b) capable of putting the rudder over from 15° on one side to15° on the other side in not more than 60 seconds with theship at its deepest seagoing draught and running ahead atone half of the maximum ahead service speed or 7 knots,whichever is the greater

DET NORSKE VERITAS


c) operated by power where necessary to meet the require-ments in b) and in any case when the rules require a rudderstock of over 230 mm diameter in way of the tiller, exclud-ing strengthening for navigation in ice.

Guidance note:Manually operated gears are only acceptable when the operationdoes not require an effort exceeding 160 N under normal condi-tions.


104 Where the main steering gear comprises two or moreidentical power units, an auxiliary steering gear need not be fit-ted, provided that:

a) in a passenger ship, the main steering gear is capable ofoperating the rudder as required in 102 b) while any one ofthe power units is out of operation

b) in a cargo ship, the main steering gear is capable of oper-ating the rudder as required in 102 b) while operating withall power units

c) the main steering gear is so arranged that after a single fail-ure in its piping system or in one of the power units the de-fect can be isolated so that steering capability can bemaintained or speedily regained.

Auxiliary gear need not be fitted when the ship is providedwith:

— two rudders, each with its own steering gear and capableof steering the vessel with any one of the rudders out of op-eration, or

— fitted with an approved alternative means of steering, suchas azimuth thruster, capable of steering the vessel with therudder out of operation and provided with approved re-mote control from the bridge or

— for non-propelled vessels.

105 In every oil carrier, chemical carrier or liquefied gas car-rier of 10 000 tons gross tonnage and upwards and in every oth-er ship of 70 000 tons gross tonnage and upwards, the mainsteering gear shall comprise two or more identical power unitscomplying with the requirements in 104.

106 Steering gears for over-balanced rudders, which are sub-ject to C108, are to be designed to prevent a sudden turn of rud-der in case of loss of steering gear torque due to a single failurein the steering gear power or control systems, inclusive failurein power supply.

Furthermore, the steering gear shall have sufficient capacity tocompensate for the friction losses in all bearings due to age andwear. Unless such losses are accounted for and specified insubmitted approval documentation, the friction coefficient forthe bearing in worn condition shall be taken at least twice aswhen new.

107 Main and auxiliary steering gear power units shall be:

a) arranged to restart automatically when power is restoredafter a power failure

b) capable of being brought into operation from a position onthe navigating bridge. In the event of a power failure toany one of the steering gear power units, an audible andvisual alarm shall be given on the navigating bridge

c) arranged so that transfer between units can be readily ef-fected.

108 Where the steering gear is so arranged that more thanone system (either power or control) can be simultaneously op-erated, the risk of hydraulic locking caused by a single failureis to be considered.

Guidance note:The “hydraulic locking” is a phenomenon which may be experi-enced when two hydraulic systems (usually identical) worksagainst each other.


109 Steering gears are to be mounted on substantial seatings,which will effectively transmit the rudder torque to the hullstructure. Deck plating under rudder carrier is to be of substan-tial thickness. Prior to installation all welding near the seatingshave to be completed. The deck underneath is to be efficientlysupported to take the weight of steering gear and rudder withrudder stock.

110 Suitable stopping arrangements are to be provided forthe rudder. The stoppers may be an integral part of the rudderactuator. Power cut-out to the actuator is to operate at a smallerangle of helm than those for the rudder, and are to be synchro-nised with the gear itself and not with the control system.

111 Steering gears, other than of the hydraulic type, will beaccepted provided the standards are considered equivalent tothe requirements of this section.

112 The steering gear compartment shall be:

a) readily accessible and, as far as practicable, separatedfrom machinery spaces

b) provided with suitable arrangements to ensure working ac-cess to steering gear machinery and controls.These arrangements shall include handrails and gratings orother non-slip surfaces to ensure suitable working condi-tions in the event of hydraulic fluid leakage.

(SOLAS reg. II-1/29.13)

113 Electrical power units are to be placed on elevated plat-forms in order to avoid water splash.

114 A means of communication according to Sec.12 B101 isto be provided.

J 200 Power actuating system, general requirements201 Rudder actuators other than those covered by the IMO“Guidelines” for non-duplicated rudder actuators, see Appen-dix A, are to be designed in accordance with the relevant re-quirements of Pt.4 Ch.7 for Class I pressure vessels(notwithstanding any exemptions for hydraulic cylinders).

202 Accumulators, if fitted, are to comply with the relevantrequirements of Pt.4 Ch.7.

203 The welding details and welding procedures are to beapproved. All welded joints within the pressure boundary of arudder actuator or connecting parts transmitting mechanicalloads are to be full penetration type or of equivalent strength.

204 The construction is to be such as to minimise local con-centrations of stress.

205 The design pressure for calculations to determine thescantlings of piping and other steering gear components sub-jected to internal hydraulic pressure shall be at least 1.25 timesthe maximum working pressure under the operational condi-tions specified in 102 b) taking into account any pressurewhich may exist in the low pressure side of the system. Fatiguecriteria may be applied for the design of piping and compo-nents, taking into account pulsating pressures due to dynamicloads (see Appendix A).

206 The permissible primary general membrane stress sub-ject to 205 is not to exceed the lower of the following values:

σb = specified minimum tensile strength of material at am-bient temperature

σb

A------ or

σy

B------

DET NORSKE VERITAS


σy = specified minimum yield stress or 0.2 per cent proofstress of the material, at ambient temperature.

A and B are given by the following table:

207 Special consideration is to be given to the suitability ofany essential component which is not duplicated. Any such es-sential component shall, where appropriate, utilise anti-frictionbearings such as ball bearings, roller bearings or sleeve bear-ings which shall be permanently lubricated or provided withlubrication fittings.

208 All steering gear components transmitting mechanicalforces to the rudder stock, which are not protected againstoverload by structural rudder stops or mechanical buffers, areto have a strength at least equivalent to that of the rule rudderstock in way of the tiller.

209 Oil seals between non-moving parts, forming part of theexternal pressure boundary, should be of the metal upon metaltype or of an equivalent type.

210 Oil seals between moving parts, forming part of the ex-ternal pressure boundary, should be duplicated, so that the fail-ure of one seal does not render the actuator inoperative.Alternative arrangements providing equivalent protectionagainst leakage may be accepted.

211 Hydraulic power operated steering gears are to be pro-vided with:

a) arrangements to maintain the cleanliness of the hydraulicfluid taking into consideration the type and design of thehydraulic system

b) a fixed storage tank having sufficient capacity to rechargeat least one power actuating system including the reser-voir, where the main steering gear is required to be poweroperated. The storage tank is to be permanently connectedby piping in such a manner that the hydraulic systems canbe readily recharged from a position within the steeringgear compartment and provided with a contents gauge.

212 Hydraulic power supply for steering gear is not to beused for other purposes.

J 300 Piping systems, relief valve arrangements301 Piping, joints, valves, flanges and other fittings are tocomply with the requirements of Pt.4 Ch.6. Power piping is tocomply with requirements to class I pipes. The design pressureis to be in accordance with 205.

302 For all vessels with non-duplicated actuators, isolatingvalves, directly fitted on the actuator, are to be provided at theconnection of pipes to the actuator.

303 Main and auxiliary steering gear are to be provided withseparate hydraulic power supply pipes. When main steeringgear is arranged in accordance with 104, each hydraulic powerunit is to be provided with separate power pipes. Interconnec-tions between power pipes are to be provided with quick oper-ating isolating valves.

304 Arrangements for bleeding air from the hydraulic sys-tem are to be provided, where necessary.

305 Relief valves are to be fitted to any part of the hydraulicsystem which can be isolated and in which pressure can begenerated from the power source or from external forces. Thesetting of the relief valves is not to exceed the design pressure.The valves are to be of adequate size and so arranged as toavoid an undue rise in pressure above the design pressure.

306 Relief valves for protecting any part of the hydraulic

system which can be isolated, as required in 305 are to complywith the following:

a) The setting pressure is not to be less than 1.25 times themaximum working pressure.

b) The minimum discharge capacity of the relief valve(s) isnot to be less than 110 per cent of the total capacity of thepumps which can deliver through it (them). Under suchconditions the rise in pressure is not to exceed 10 per centof the setting pressure. In this regard, due consideration isto be given to extreme foreseen ambient conditions in re-spect of oil viscosity.

307 Flexible hoses of approved type may be installed be-tween two points where flexibility is required but are not to besubjected to torsional deflection (twisting) under normal oper-ating conditions. In general, the hose should be limited to thelength necessary to provide for flexibility and for proper oper-ation of machinery.

308 Hoses are to be high pressure hydraulic hoses accordingto recognised standards and suitable for the fluids, pressures,temperatures and ambient conditions in question. For detailedrequirements for construction and testing of flexible hoses, seePt.4 Ch.6 Sec.6 D.

J 400 Rudder actuator401 The actuator housing may be cast or welded construc-tion. Parts subjected to internal pressure are to satisfy the de-sign requirements in 200.

402 The structural design is to be chosen with due respect totransmission of reaction forces to the seatings.

403 The rudder carrier, or in case of an integral unit, the rud-der actuator and its fastening to foundations, is to be able totake reaction forces due to bending set up in rudder stock. Sidechocks may be required in addition to fitted bolts.

404 The permissible equivalent stress in tiller arms, rotorvanes, stoppers, piston rods, rams, guides and other similarparts, where calculations are based on the rule rudder torque,MTR is:

and where calculated at the design pressure:

For certain parts, which are not subject to reversed load, per-missible stress at the design pressure may be increased to:

Permissible bending stress in rotor vanes calculated at designpressure is:

Fillets are to be smooth and well rounded to give reasonablelow stress concentrations (geometrical stress concentration(factor) ≤1.5).

Relevant stresses due to pretensioning of bolts, or shrink fittingof hubs, etc. are to be duly considered.

σ e = permissible von Mises equivalent stress in N/mm2

σ f = yield strength of the material in N/mm2 (see B200)f1 = material factor, see B204σ fit = static stress due to pretension or shrinkage in N/mm2.

Tangential shrink fitting stress at the hub surface may be taken

Table J1 Permissible primary membrane stressSteel Cast steel Nodular cast iron

AB

3.51.7

42

53

σ e 118f1 1σ fit

σf--------–

(N/mm

2 )≤

σ e 150f1 1σ fit

σf--------–

(N/mm

2 )≤

σ e 185f1 1σ fit

σf--------–

(N/mm

2 )≤

σ b 1.5σAB 1σ fit

σf--------–

(N/mm

2 )≤

DET NORSKE VERITAS


as follows:

σb = permissible bending stress in N/mm2

σAB = smaller of the or in 206

p = actual pressure due to shrinkage in N/mm2 (seeG200).

Average hub thickness in way of vanes shall normally not beless than 70% of required vane root thickness.

Design torqueTdes of a rudder actuator for calculation of rud-der stock connection is to be taken as:

Tdes is not to exceed:

p = steering gear design pressure (MPa)n = number of active pistons or vanesA = piston or vane (projected) area (mm2) l = torque arm (m), see Fig. 15θ = rudder angle = 0°C for rotary vane and linked cylinder type actuator = maximum permissible rudder angle (normally 35°) for

ram type actuatorΦ = as defined in Fig. 15 = 0° for ram and rotary vane type actuatord = rudder stock minimum diameter below tiller or rotor

(mm)kb = bending moment factor, see G201.

The shearing force based on rule rudder torque in each of thearms or vanes may be expressed as:

Corresponding bending moment at the root of arms or vanesmay be expressed as:

The effective shear area of arms or vanes is, however, not to beless than (greater of the values applies):

l = length of tiller arm measured from centre of rudderstock to point of action of driving force in m

n = number of arms or vanes (not to be taken greater than3)

d = diameter of tiller boss, in md so = rule diameter of rudder stock at tiller, see G200, in mmM TR = rule rudder torque, see D200.

The value of l will depend on the design of the tiller or rotorand also on the angle of helm as illustrated in Fig. 15.

405 Hydraulic cylinder type actuators are to comply with re-quirements for buckling strength given in Pt.4 Ch.6.

Fig. 15Steering gears

σfit p1 ce

2+

1 ce2

–----------------- 1–

(N/mm2 )=

σb

A------

σy

B------

TdespnAl Φcos

θcos--------------------------10

3– (kNm)=

Tdes 2f1d

42kb-----------

3 (kNm)=

PA

MTR

nl------------ (kN)=

MA PA ld2---–

(kNm)=

AA

dso3

5000nl----------------- or

pA50f1---------- (mm

2 )=

DET NORSKE VERITAS


J 500 Steering gear control and monitoring systems, general requirements

501 For instrumentation and automation, including compu-ter based control and monitoring, the requirements in thischapter are additional to those given in Pt.4 Ch.9.

502 Steering gear control system is the equipment by whichorders are transmitted from the navigation bridge to the steer-ing gear power units. Steering gear control systems comprisetransmitters, receivers, hydraulic control pumps and their asso-ciated motors, motor controllers, piping and cables.

503 Steering gear control shall be provided:

a) for the main steering gear, both on the navigating bridgeand in the steering gear compartment

b) where the main steering gear is arranged in accordancewith 104 by two independent control systems, both opera-ble from the navigating bridge. This does not require du-plication of the steering wheel or steering lever. Where thecontrol system consists of an hydraulic telemotor, a sec-ond independent system operable from the bridge need notbe fitted, except in an oil carrier, chemical carrier or lique-fied gas carrier of 10 000 tons gross and upwards

c) for the auxiliary steering gear, in the steering gear com-partment and, if power operated, it shall also be operablefrom the navigating bridge and shall be independent of thecontrol system for the main steering gear.

504 Any main and auxiliary steering gear control system op-erable from the navigating bridge shall comply with the fol-lowing:

a) If electric, it shall be served by its own separate circuitsupplied from a steering gear power circuit from a pointwithin the steering gear compartment, or directly fromswitchboard busbars supplying that steering gear powercircuit at a point on the switchboard adjacent to the supplyto the steering gear power circuit.

b) Means shall be provided in the steering gear compartmentfor disconnecting any control system operable from thenavigating bridge from the steering gear it serves.

c) The system shall be capable of being brought into opera-tion from a position on the navigating bridge.

d) In the event of a failure of electrical power supply to thecontrol system, an audible and visual alarm shall be givenon the navigating bridge.

e) Short circuit protection only shall be provided for steeringgear control supply circuits.

505 The electric power circuits and the steering gear controlsystems with their associated components, cables and pipes areto be separated as far as is practicable throughout their length.

506 When two or more exclusive electric control systems areused, these are to be kept separated with separate cables andare not to be located in the same enclosure. Regarding arrange-ments in steering stands, this requirement may be waived, pro-vided the systems are securely installed and separated as far aspracticable.

Steering order devices for exclusive electric control systemsmay be operated by the same wheel or lever shaft.

Steering mode and steering station selectors for exclusive elec-tric systems may also be operated by the same shaft, providedthe arrangement is of reliable construction.

507 If additional steering stations are arranged with controlcircuits branched off from a main steering station, it is to bepossible to disconnect each such circuit by a multipole switchon the main steering station.

J 600 Control gear for steering motors

601 Steering gear motors are to be provided with controlgear according to requirements given in Pt.4 Ch.8 Sec.2 H200and Sec.2 G502. The control gear is, however, not to haveovercurrent or other overload releases.

602 Steering gear motors are to be remote controlled fromthe bridge and local controlled from the steering gear compart-ment. When remote control is arranged from two or more po-sitions, the arrangement is to be such that the motor can bestarted independently from any of these positions.

603 The control circuit of each steering gear motor is to besuch that a motor in operation will restart automatically uponrestoration of voltage after a power failure.

J 700 Indications and alarms

701 Alarm and indication requirements are specified in Ta-ble J2.

702 All alarms associated with steering gear faults are to beindicated on the navigating bridge and in machinery spacewhere they can be readily observed.

703 The rudder angle indicating system is to be independentof any control system and so arranged that a single failure inpower supply or anywhere in the indication system does notcause loss of rudder angle indication on the bridge.

704 Where hydraulic locking, caused by a single failure,may lead to loss of steering, an alarm, which identifies thefailed system, is to be provided.

Guidance note:This alarm should be activated when there is disagreement be-tween the given order versus control system output/execution.For instance when:

- position of the variable displacement pump control systemdoes not correspond with given order; or

- incorrect position of 3-way full flow valve or similar in con-stant delivery pump system is detected.


J 800 Power supply and distribution

801 Power supply is to be arranged with redundancy. Forships where main source of electric power is arranged withoutredundancy, the steering gear is to be arranged in such a waythat steering from the bridge will be possible also after loss ofmain electric power, e.g. by means of direct hand-hydraulicsteering.

802 At least two exclusive circuits are to be provided foreach electric or electrohydraulic steering gear arrangementcomprising one or more power units.

803 Each of the exclusive circuits is to be fed from the mainswitchboard, however, one circuit may pass through the emer-gency switchboard.

804 One of these circuits may supply an associated auxiliaryelectric or electrohydraulic steering gear.

805 Each of these circuits is to have adequate capacity tosupply all motors which may be connected and operated simul-taneously.

806 In ships of less than 1600 gross tonnage, if provided withan auxiliary steering gear independent of electrical power sup-ply, the main steering gear may be fed by one circuit from themain switchboard.

807 Where the rudderstock is required to be over 230 mm di-ameter (excluding ice strengthening) in way of the tiller, an al-ternative power supply shall be provided automatically within45 seconds, either from the emergency source of electricalpower or from an independent source of power located in the

DET NORSKE VERITAS


steering gear compartment.

J 900 Emergency power supply901 Where the rudder stock is required to be over 230 mmdiameter in way of the tiller, excluding strengthening for nav-igation in ice, an alternative power supply, sufficient at least tosupply the steering gear power unit which complies with therequirements in 103 and also its associated control system andthe rudder angle indicator, shall be provided automatically,within 45 seconds, either from the emergency source of elec-trical power or from an independent source of power located inthe steering gear compartment. This independent source ofpower shall be used only for this purpose.

902 In every ship of 10 000 gross tonnage and upwards, thealternative power supply shall have a capacity for at least 30minutes of continuous operation and in any other ship for atleast 10 minutes.

903 Where the alternative power source is a generator, or anengine driven pump, starting arrangements are to comply withthe requirements relating to the starting arrangements of emer-gency generators.

J 1000 Operating instructions1001 Appropriate operating instructions with a block dia-gram showing the change-over procedures for steering gearcontrol systems and steering gear actuating systems are to bepermanently displayed in the wheelhouse and in the steeringgear compartment.

1002 Where the system failure alarms according to 704 areprovided, appropriate instructions are to be given to shut downthe failed system.

J 1100 Additional requirements for oil carriers, chemical carriers and liquefied gas carriers of 10 000 tons gross and upwards1101 Every oil carrier, chemical carrier or liquefied gas car-rier of 10 000 tons gross and upwards are, subject to 1102 tocomply with the following:

a) The main steering gear is to be so arranged that in theevent of loss of steering capability due to a single failurein any part of one of the power actuating systems of themain steering gear, excluding the tiller, quadrant or com-ponents serving the same purpose, or seizure of the rudderactuators, steering capability is to be regained in not morethan 45 seconds after the loss of one power actuating sys-tem.

b) The main steering gear is to comprise either:

— two independent and separate power actuating sys-tems, each capable of meeting the requirements in 102b), or

— at least two identical power actuating systems which,acting simultaneously in normal operation, are to becapable of meeting the requirements in 102 b). Wherenecessary to comply with this requirement, inter-con-nection of hydraulic power actuating systems is to beprovided. Loss of hydraulic fluid from one system isto be capable of being detected and the defective sys-tem automatically isolated so that the other actuatingsystem or systems are to remain fully operational.

c) Steering gears other than of the hydraulic type are toachieve equivalent standards.

1102 For oil carriers, chemical carriers or liquefied gas car-riers of 10 000 tons gross and upwards, but of less than 100 000tonnes deadweight, solutions other than those set out in 1101,which need not apply the single failure criterion to the rudderactuator or actuators, may be permitted provided that an equiv-alent safety standard is achieved and that:

a) following loss of steering capability due to a single failureof any part of the piping system or in one of the powerunits, steering capability is to be regained within 45 sec-onds, and

b) where the steering gear includes only a single rudder actu-ator, special consideration is given to stress analysis forthe design including fatigue analysis and fracture mechan-ics analysis, as appropriate, to the material used, to the in-stallation of sealing arrangements and to testing andinspection and to the provision of effective maintenance.In consideration of the foregoing, regard will be given tothe IMO «Guidelines» for non-duplicated rudder actua-tors, given in Appendix A.

K. Testing

K 100 Sternframes101 Built sternframes with closed sections are to be pressuretested on completion.

K 200 Rudders and rudder stock connections201 Contact area of conical connections is to be (minimum70%) verified by means of paint test (e.g. tool-maker blue) in

Table J2 Monitoring requirements for steering gear

Item AlarmIndication

Remarkssubject position

Rudder position Rudder angle Bridge and steering gear compartment

Steering gear power units Power failure Phase failure Motor overload

Running Bridge and machinery space

Steering gear Hydraulic lock Shall identify failed sys-tem

Steering gear control sys-tem

Power failure plus alarms as required in Pt.4 Ch.9 Sec.2 C

Ready for operation Dis-connection of bridge con-trol system

Bridge Low pressure alarm is re-quired when control sys-tem is not integrated in the main system

Steering gear hydraulic system oil tanks (each - in-clusive steering control system tanks)

Low level Low level alarm indication is not to be combined with other alarms on the bridge 1)

Storage tank Oil level Content gauge on the tankAuto pilot Failure Running Bridge Alarm on bridge only1) Low level alarm in separate steering gear control system oil tanks may be substituted by low pressure alarm. It is provided that each of the systems is able

to control the main steering gear alone, and that oil leakage in one system has no effect on the other one

DET NORSKE VERITAS


presence of the surveyor.

202 Test pull-up followed by control of contact area may berequired before final assembly for conical keyless connectionsintended for injection fitting, if calculations are considered in-accurate due to a non-symmetric design or other relevant rea-sons. Pull-up length during test pull-up is not to be less thanfinal pull-up length.

K 300 Steering gears301 The requirements of the rules relating to the testing ofclass I pressure vessels, piping, and related fittings apply. Testpressure for internal pressure testing is to be 1.5 times the de-sign pressure.

302 After installation on board the vessel the steering gear isto be subjected to the required hydrostatic and running tests.

303 On double rudder installation where the two units aresynchronised by mechanical means, mutual adjustment is to betested.

304 For testing and certification of hydraulic, electrical andinstrumentation and/or automation parts and systems, see Pt.4Ch.6, Pt.4 Ch.8 and Pt.4 Ch.9, respectively.

305 Each type of power unit pump is to be subjected to a typetest. The type test shall be for a duration of not less than 100hours, the test arrangements are to be such that the pump mayrun in idling conditions, and at maximum delivery capacity atmaximum working pressure. During the test, idling periods areto be alternated with periods at maximum delivery capacity atmaximum working pressure. The passage from one conditionto another should occur at least as quickly as on board. Duringthe whole test no abnormal heating, excessive vibration or oth-er irregularities are permitted. After the test, the pump is to bedismantled and inspected. Type tests may be waived for a pow-er unit which has been proven to be reliable in marine service.

K 400 Trials401 The steering gear is to be tried out on the trial trip in or-der to demonstrate to the surveyor's satisfaction that the re-quirements of the rules have been met. (The designrequirement given in J102 d) need not be proved by trials atmaximum astern speed and maximum rudder angles.) The trialis to include the operation of the following:

a) Trial conditions:

— loaded on summer load waterline— running ahead at maximum service speed correspond-

ing to maximum nominal shaft RPM and maximumcontinuous rating (MCR) of the main engine(s) and ifequipped with controllable pitch propeller(s), the pro-peller pitch is to be at the maximum design pitch cor-responding to the nominal shaft RPM and MCR of themain engine(s).If the vessel cannot be tested on summer load water-line, alternative trial conditions may be specially con-sidered. See 402 and 403.

a1) Main steering gear trial:

— turning the rudder over from 35° on one side to 35° onthe other side and vice versa

— from 35° on either side to 30° on the other sides re-spectively within required time as given in J102, or ifclass notation Tug, Supply Vessel, or Ice ClassesICE 05-15 or POLAR 10-30, or Icebreaker in therespective rule sections.Where main steering gear comprises two or moreidentical power units, the steering gear is to be testedwith each power unit individually and all together,provided these are intended for simultaneous running.For capacity versus number of power units in opera-tion, see J104. For overbalanced rudders, see J106 andA301.

a2) Auxiliary steering gear trial:

— turning the rudder over from 15° on one side to 15° onthe other side in not more than 60 seconds with theship on summer load waterline and running ahead atone half of the maximum ahead service speed or 7knots, whichever is the greater.

b) the steering gear power units, including transfer betweensteering gear power units

c) the isolation of one power actuating system, checking thetime for regaining steering capability

d) the hydraulic fluid recharging system

e) the emergency power supply required in J900

f) the steering gear controls, including transfer of control andlocal control

g) the means of communication between the steering gearcompartment and the wheelhouse, also the engine room, ifapplicable

h) the alarms and indicators

i) where steering gear is designed to avoid hydraulic lockingthis feature shall be demonstrated.

Test items d), g) and h) may be effected at the dockside.

402 When performance test is carried out with reduceddraught with partly submerged rudder, calculations showingcorresponding rudder force and torque for the trials are to besubmitted on request.

403 Ships fitted with semi-spade rudders are normally to betested with the rudders completely submerged. However, whensatisfactory results are proved by sister ships, tests accordingto 402 with partly submerged rudder may be accepted. Calcu-lations of the expected rudder force and torque for the trials areto be submitted. If test results for sisterships are not available,steering gear test with rudder partly submerged may be accept-ed upon special consideration in each case.

DET NORSKE VERITAS


SECTION 3ANCHORING AND MOORING EQUIPMENT

A. General

A 100 Introduction101 The requirements in this section apply to equipment andinstallation for anchoring and mooring.

102 Towlines and mooring lines are not subject to classifica-tion. Lengths and breaking strength are, however, given in theequipment tables as guidance. If certification of materials isneeded voluntarily, it shall be done in accordance with 204.

A 200 Documentation201 The following plans and particulars are to be submittedfor approval:

— equipment number calculations— equipment (list) including type of anchor, grade of anchor

chain, type and breaking load of steel and fibre ropes— anchor design if different from standard or previously ap-

proved anchor types. Material specification— windlass design. Material specifications for cable lifters,

shafts, couplings and brakes— chain stopper design. Material specification.

202 The following plans and particulars are to be submittedfor information:

— arrangement of deck equipment.

203 For barges the towline fastening arrangement and de-tails, stating towing force is to be submitted for approval.

204 Det Norske Veritas Product Certificate (NV) (for mate-rials, ISO 10474: Type 3.1 C) will be required for the follow-ing items:

— anchor and anchor shackle— anchor chain cable and accessories (shackles, swivels,

etc.)— windlass cable lifter— winch drum and drum flanges— shafts for cable lifter and/or drum— pawl wheel, stopper and couplings— gear shafts and wheels (W)— windlass/winch frame work (W)— brake components— chain stopper— steel wire ropes (W)— fibre ropes (W).

For items above marked with (W), work's certificate (for ma-terials, ISO 10474: Type 3.1 B) from approved manufacturerwill normally be accepted.

A 300 Assumptions301 The anchoring equipment required is the minimum con-sidered necessary for temporary mooring of a vessel in moder-ate sea conditions when the vessel is awaiting berth, tide, etc.The equipment is therefore not designed to hold a vessel offfully exposed coasts in rough weather or for frequent anchor-ing operations in open sea. In such conditions the loads on theanchoring equipment will increase to such a degree that itscomponents may be damaged or lost owing to the high energyforces generated.

Guidance note:If the intended service of the vessel is such that frequent anchor-ing in open sea is expected, it is advised that the size of anchorsand chains is increased above the rule requirements, taking into

account the dynamic forces imposed by the vessel moving inheavy seas. The Equipment Numeral (EN) formula for requiredanchoring equipment is based on an assumed current speed of 2.5m/s, wind speed of 25 m/s and a scope of chain cable between 6and 10, the scope being the ratio between length of chain paid outand water depth.


302 The anchoring equipment required by the Rules is de-signed to hold a vessel in good holding ground in conditionssuch as to avoid dragging of the anchor. In poor holdingground the holding power of the anchors will be significantlyreduced.

303 It is assumed that under normal circumstances the vesselwill use only one bower anchor and chain cable at a time.

B. Structural Arrangement for Anchoring Equipment

B 100 General

101 The anchors are normally to be housed in hawse pipes ofsuitable size and form to prevent movement of anchor andchain due to wave action.

The arrangements are to provide an easy lead of the chain cablefrom the windlass to the anchors. Upon release of the brake,the anchor is immediately to start falling by its own weight. Atthe upper and lower ends of hawse pipes, there are to be chaf-ing lips. The radius of curvature is to be such that at least 3links of chain will bear simultaneously on the rounded parts atthe upper and lower ends of the hawse pipes in those areaswhere the chain cable is supported during paying out and hoist-ing and when the vessel is laying at anchor. Alternatively, roll-er fairleads of suitable design may be fitted.

Where hawse pipes are not fitted alternative arrangements willbe specially considered.

102 The shell plating in way of the hawse pipes is to be in-creased in thickness and the framing reinforced as necessary toensure a rigid fastening of the hawse pipes to the hull.

103 Ships provided with a bulbous bow, and where it is notpossible to obtain ample clearance between shell plating andanchors during anchor handling, local reinforcements of bul-bous bow are to be provided as necessary.

104 The chain locker is to have adequate capacity and a suit-able form to provide a proper stowage of the chain cable, andan easy direct lead for the cable into the chain pipes, when thecable is fully stowed. Port and starboard cables are to have sep-arate spaces. If 3 bower anchors and 3 hawse pipes are used,there are to be 3 separate spaces. The chain locker boundariesand access openings are to be watertight. Provisions are to bemade to minimise the probability of chain locker being floodedin bad weather. Adequate drainage facilities of the chain lockerare to be adopted.

Provisions are to be made for securing the inboard ends ofchain to the structure. This attachment is to be able to with-stand a force of not less than 15% nor more than 30% of theminimum breaking strength of the chain cable. The fasteningof the chain to the ship is to be made in such a way that in caseof emergency when anchor and chain have to be sacrificed, thechain can be readily made to slip from an accessible positionoutside the chain locker.

105 The windlass and chain stoppers are to be efficiently

DET NORSKE VERITAS


bedded to the deck. The deck plating in way of windlass andchainstopper is to be increased in thickness and supported bypillars carried down to rigid structures. See Sec.5 B.

C. Equipment Specification

C 100 Equipment number101 The equipment number is given by the formula:

E N = ∆2/3 + 2 B H + 0.1 A

H = effective height in m from the summer load waterlineto the top of the uppermost deckhouse, to be measuredas follows:

H = a + Σ hi

a = distance in m from summer load waterline amidshipsto the upper deck at side

hi = height in m on the centre line of each tier of houses

having a breadth greater than B/4. For the lowest tier,hi is to be measured at centre line from the upper deck,or from a notional deck line where there is local dis-continuity in the upper deck

A = area in m2 in profile view of the hull, superstructuresand houses above the summer load waterline, which iswithin L of the ship. Houses of breadth less than B/4are to be disregarded.

In the calculation of Σ hi and A sheer and trim are to be ig-nored.

Windscreens or bulwarks more than 1.5 m in height are to beregarded as parts of superstructures and of houses when deter-mining H and A. The total area of the mentioned items meas-ured from the deck, is to be included.

The area of hatch coamings more than 1.5 m in height abovedeck at side is to be included in A.

102 For a barge rigidly connected to a push-tug the equip-ment number is to be calculated for the combination regardedas one unit.

Table C1 Equipment table, general

Equipment number

Equip-ment letter

Stockless bower anchors Stud-link chain cables Towline

(guidance)Mooring lines 1) (guidance)

Number

Mass per an-

chor

kg

Total length Diameter and steel grade Steel or fibre ropes Steel or fibre ropes

m

NV K1

mm

NV K2

mm

NV K3

mm

Mini-mum

length m

Minimum breaking strength

kN

Number

Length of each

m


kN30-4950-6970-8990-109

a0abc

2222

120180240300

192.5220220

247.5

12.51416

17.5

12.51416

170180180180

88.598.098.098.0

2333

8080100110

32343739

110-129130-149150-174

def

222

360420480

247.5275275

1920.522

17.517.519

180180180

989898

333

110120120

444954

175-204205-239240-279

ghi

222

570660780

302.5302.5330

242628

20.52224

20.522

180180180

112129150

344

120120120

596469

280-319320-359360-399

jkl

222

90010201140

357.557.5385

303234

262830

242426

180180180

174207224

444

140140140

747888

400-449450-499500-549

mno

222

129014401590

385412.5412.5

363840

323434

283030

180180190

250277306

444

14040160

98108123

550-599600-659660-719

pqr

222

174019202100

440440440

424446

363840

323436

190190190

338371406

444

160160160

132147157

720-779780-839840-909

stu

222

228024602640

467.5467.5467.5

485052

424446

363840

190190190

441480518

444

170170170

172186201

910-979980-1059

1060-1139

vwx

222

285030603300

495495495

545658

485050

424446

190200200

559603647

444

170180180

216230250

1140-12191220-12991300-1389

yzA

222

354037804050

522.5522.5522.5

606264

525456

464850

200200200

691738786

444

180180180

270284309

1390-14791480-15691570-1669

BCD

222

432045904890

550550550

666870

586062

505254

200220220

836888941

455

180190190

324324333

1670-17891790-19291930-2079

EFG

222

525056106000

577.5577.5577.5

737678

646668

565860

220220220

102411091168

555

190190190

353378402

2080-22292230-23792380-2529

HIJ

222

645069007350

605605605

818487

707376

626466

240240240

125913561453

555

200200200

422451480

2530-26992700-28692870-3039

KLM

222

780083008700

632.5632.5632.5

909295

788184

687073

260260260

147114711471

666

200200200

480490500

DET NORSKE VERITAS


C 200 Equipment tables201 The equipment is in general to be in accordance with therequirements given in Table C1.

The two bower anchors and their cables are to be connectedand stowed in position ready for use. The total length of chaincable required is to be equally divided between the two an-chors. The towline and the mooring lines are given as guidanceonly, representing a minimum standard, and are not to be con-sidered as conditions of class.

Guidance note:If anchor chain total length is an uneven number of shackles, nomore than one standard shackle (27.5 m) difference in length isallowed between the two anchors.


202 For fishing vessels the equipment is to be in accordancewith the requirements given in Table C2. When the equipment

number is larger than 720, table C1 should be applied.

203 Unmanned barges are only to have equipment consistingof 2 mooring lines with length as required by Table C1.

204 For ships and manned barges with restricted service theequipment specified in Table C1 and C2 may be reduced in ac-cordance with Table C3. No reductions are given for class no-tations R0 and R1.

205 For ships and manned barges with equipment numberEN less than 205 and fishing vessels with EN less than 500 theanchor and chain equipment specified in Table C1 and C2 maybe reduced, on application from the Owners, based upon a spe-cial consideration of the intended service area of the vessel.The reduction is not to be more than given for the service no-tation R4 in Table C3. In such cases a minus sign will be givenin brackets after the equipment letter for the vessel in the“Register of vessels classed with DNV”, e.g. f(–).

3040-32093210-33993400-3599

NOP

222

93009900

10500

660660660

97100102

848790

767878

280280280

147114711471

666

200200200

520554588

3600-37993800-39994000-4199

QRS

222

111001170012300

687.5687.5687.5

105107111

929597

818487

300300300

147114711471

667

200200200

618647647

4200-43994400-45994600-4799

TUV

222

129001350014100

715715715

114117120

100102105

879092

300300300

147114711471

777

200200200

657667677

4800-49995000-51995200-5499

WXY

222

147001540016100

742.5742.5742.5

122124127

107111111

959797

300300300

147114711471

788

200200200

686686696

5500-57995800-60996100-6499

ZA*B*

222

169001780018800

742.5742.5742.5

130132137

114117120

100102107

300300300

147114711471

889

200200200

706706716

6500-68996900-73997400-7899

C*D*E*

222

200002150023000

770770770

124127132

111114117

300300300

147114711471

91011

200200200

726726726

7900-83998400-88998900-93999400-9999

F*G*H*I*

2222

24500260002750029000

770770770770

137142147152

122127132132

300300300300

1471147114711471

11121314

200200200200

735735735735

10000-1069910700-1149911500-12399

J*K*L*

222

310003300035500

770770770

137142147

151617

200200200

735735735

12400-1339913400-1459914600-16000

M*N*O*

222

385004200046000

770770770

152157162

181921

200200200

735735735

1) For individual mooring lines with breaking force above 490 kN according to the table, the strength may be reduced by the corresponding increase of the number of mooring lines and vice versa. The total breaking force of all mooring lines on board should not be less than according to the table. However, the number of mooring should not be less than 6, and no line should have a breaking force less than 490 kN.

Table C1 Equipment table, general (Continued)

Equipment number

Equip-ment letter


(guidance)Mooring lines 1) (guidance)

Number

Mass per an-

chor

kg

Total length Diameter and steel grade Steel or fibre ropes Steel or fibre ropes

m

NV K1

mm

NV K2

mm

NV K3

mm

Mini-mum

length m


kN

Number

Length of each

m


kN

DET NORSKE VERITAS


D. Anchors

D 100 General101 Anchor types dealt with are:

— ordinary stockless bower anchor— ordinary stocked bower anchor— H.H.P. (“High Holding Power”) anchor— S.H.H.P. ("Super High Holding Power") anchor.

102 The mass of ordinary stockless bower anchors is not tobe less than given in C. The mass of individual anchors mayvary by 7% of the table value, provided that the total mass ofanchors is not less than would have been required for anchorsof equal mass.

The mass of the head is not to be less than 60% of the table val-ue.

103 The mass of stocked bower anchor, the stock not includ-ed, is not to be less than 80% of the table-value for ordinarystockless bower anchors. The mass of the stock is to be 25% ofthe total mass of the anchor including the shackle, etc., but ex-cluding the stock.

104 For anchors approved as H.H.P. anchors, the mass is notto be less than 75% of the requirements given in C. In such cas-es the letter r will follow the equipment letter entered in the“Register of vessels classed with DNV”.

105 For anchors approved as S.H.H.P. anchors, the mass isnot to be less than 50% of the requirements given in C. In suchcases the letter rs will follow the equipment letter entered inthe "Register of vessels classed with DNV".

106 The use of S.H.H.P. anchors is limited to vessels withservice restriction notation R1 or stricter.

107 The S.H.H.P. anchor mass is not to exceed 1500 kg.

D 200 Materials

201 Anchor heads may be cast, forged or fabricated fromplate materials. Shanks and shackles may be cast or forged.

202 The materials are to comply with relevant specificationgiven in Pt.2.

Plate material in welded anchors is to be of the grades as givenin F200 Table F3.

203 Anchors made of nodular cast iron may be accepted insmall dimensions subject to special approval of the manufac-turer.

204 Fabricated anchors are to be manufactured in accord-ance with approved welding procedures using approved weld-ing consumables and carried out by qualified welders.

Table C2 Equipment table for fishing vessels and sealers

Equip-ment

number

Equip - ment letter


(guidance)Mooring lines

(guidance)

Number

Mass per anchor

kg

Total length

Diameter and steel grade Steel or fibre ropes Steel or fibre ropes

m

NV K1

mm

NV K2

mm

Minimum length

m


kN

Number

Length of

each

m

Mini-mum

breaking strength

kN30-3940-4950-5960-69

a0f1a0f2af1af2

2222

80100120140

165192.5192.5192.

1111

12.512.5

180180

9898

2233

50608080

29293434

70-7980-8990-99

100-109

bf1bf2cf1cf2

2222

160180210240

220220220220

14141616

12.512.51414

180180180180

98989898

3333

100100110110

37373939

110-119120-129130-139140-149

df1df2ef1ef2

2222

270300340390

247.5247.5275275

17.517.51919

1616

17.517.5

180180180180

98989898

3333

110110120120

44444949

150-174175-204205-239240-279

fghi

2222

480570660780

275302.5302.5330

22242628

1920.52224

180180180180

98112129150

3344

120120120120

54596469

280-319320-359360-399

jkl

222

90010201140

357.5357.5385

303234

262830

180180180

174207224

444

140140140

747888

400-449450-499500-549

mno

222

129014401590

385412.5412.5

363840

323434

180180190

250277306

444

140140160

98108123

550-599600-659660-720

pqr

222

174019202100

440440440

424446

363840

190190190

338371406

444

160160160

132147157

Table C3 Equipment reductions for service restriction notations. (See Table C1)

Class notation

Stockless bower anchors

Stud-link chain cables

Number Mass change per

anchor

Length reduction

Diameter

R2 R3 R4 RE

2222

- 10% - 20% - 30% - 40%

No red.No red. - 20% - 30%

No red.No red. - 10% - 20%

Alternatively:R3 R4 RE

111

+40%No change

- 20%

- 40% - 50% - 60%

No red.No red. - 10%

DET NORSKE VERITAS


D 300 Anchor shackle301 The diameter of the shackle leg is normally not to be lessthan:

ds = 1.4 dc

dc = required diameter of stud chain cable with tensilestrength equal to the shackle material, see Table C1 orC2. For shackle material different from the steel gradesNV K1, NV K2 and NV K3, linear interpolation be-tween table values of dc will normally be accepted.

302 The diameter of the shackle pin is normally not to be lessthan the greater of:

dp = 1.5 dc

dp = 0.7 l p

dc = as given in 301 lp = free length of pin. It is assumed that materials of the

same tensile strength are used in shackle body and pin.For different materials dp will be specially considered.

D 400 Testing401 Ordinary anchors with a mass more than 75 kg, orH.H.P. anchors with a mass more than 56 kg, or S.H.H.P. an-chors with a mass more than 38 kg, are to be subjected to prooftesting in a machine specially approved for this purpose.

402 The proof test load is to be as given in Table D1, depend-ent on the mass of equivalent anchor, defined as follows:

— Total mass of ordinary stockless anchors.— Mass of ordinary stocked anchors excluding the stock.— 4/3 of the total mass of H.H.P. anchors— 2 times of the total mass of S.H.H.P. anchors.

For intermediate values of mass the test load is to be deter-mined by linear interpolation.

403 The proof load is to be applied on the arm or on the palmat a distance from the extremity of the bill equal to 1/3 of thedistance between it and the centre of the crown. The anchorshackle may be tested with the anchor.

404 For stockless anchors, both arms are to be tested simul-taneously, first on one side of the shank and then on the otherside.

For stocked anchors, each arm is to be tested individually.

405 The anchors are to withstand the specified proof loadwithout showing signs of injurious defects defects.

This is to be confirmed by visual inspection after proof loadtesting. S.H.H.P. anchors and the welds of fabricated anchors,regardless of anchor type, are in addition subject to magneticparticle testing.

406 In every test the difference between the gauge lengths(as shown in figures) where one-tenth of the required load wasapplied first and where the load has been reduced to one-tenthof the required load from the full load may be permitted not toexceed one percent (1%).

Fig. 1Gauge length

D 500 Additional requirements for H.H.P. and S.H.H.P. anchors

501 H.H.P. and S.H.H.P. anchors are to be designed for ef-fective hold of the sea bed irrespective of the angle or positionat which they first settle on the sea bed after dropping from anormal type of hawse pipe. In case of doubt a demonstration ofthese abilities may be required.

502 The design approval of H.H.P. and S.H.H.P. anchors arenormally given as a type approval, and the anchors are listed inthe Register of Type Approved Products No.3 "StructuralEquipment, Containers, Cargo Handling and Securing Equip-ment".

The design approval of H.H.P. anchors is normally given as atype approval, and the anchors are listed in the "Register ofType Approved Products No.3: Containers, Cargo Handling,Lifting Appliances and Miscellaneous Equipment."

503 H.H.P. anchors for which approval is sought are to betested on sea bed to show that they have a holding power perunit of mass at least twice that of an ordinary stockless boweranchor.

504 S.H.H.P. anchors for which approval is sought are to betested on sea bed to show that they have a holding power perunit of mass at least 4 times that of an ordinary stockless bower

anchor.

505 If approval is sought for a range of H.H.P. anchor sizes,at least two sizes are to be tested. The mass of the larger anchorto be tested is not to be less than 1/10 of that of the largest an-chor for which approval is sought. The smaller of the two an-chors to be tested is to have a mass not less than 1/10 of that ofthe larger.

506 If approval is sought for a range of S.H.H.P. anchor siz-es, at least three sizes are to be tested, indicative of the bottom,middle and top of the mass range.

507 Each test is to comprise a comparison between at leasttwo anchors, one ordinary stockless bower anchor and oneH.H.P. or S.H.H.P. anchor. The mass of the anchors are to beas equal as possible.

508 The tests are to be conducted on at least 3 different typesof bottom, which normally are to be: soft mud or silt, sand orgravel, and hard clay or similar compacted material.

509 The tests are normally to be carried out by means of atug. The pull is to be measured by dynamometer or determinedfrom recently verified curves of the tug's bollard pull as func-tion of propeller r.p.m.

The diameter of the chain cables connected to the anchors is tobe as required for the equipment letter in question. During the

DET NORSKE VERITAS


test the length of the chain cable on each anchor is to be suffi-cient to obtain an approximately horizontal pull on the anchor.Normally, a horizontal distance between anchor and tug equalto 10 times the water depth will be sufficient.

D 600 Identification

601 The following marks are to be stamped on one side ofthe anchor:

— Mass of anchor (excluding possible stock)— H.H.P., when approved as high holding power anchor— S.H.H.P., when approved as super high holding power an-

chor— Certificate No.— Date of test— Det Norske Veritas' stamp.

E. Anchor Chain Cables

E 100 General

101 Chain cables are to be made by makers approved by theSociety for the pertinent type of chain cable, size and methodof manufacture.

102 The form and proportion of chain cable links and shack-les are normally to be in accordance with Fig. 2. Deviation inaccordance with International Standard ISO/1704-1991, willbe generally accepted.

Other design solutions, e.g. short link chain cable or steel wirerope may be accepted after special consideration.

103 The diameter of stud link chain cable is not to be lessthan given in C.

104 If ordinary short link chain cable is accepted instead ofstud link chain cable at least the same proof load will normallybe required.

For fishing vessels with equipment number EN ≤ 110 the di-ameter is to be at least 20% in excess of the table value for thesteel grade used.

105 Steel wire rope instead of stud link chain cable may beaccepted for vessels of special design or operation, for vesselswith restricted services and for fishing vessels. The acceptancewill be based on a case-by-case evaluation, including consid-eration of operational and safety aspects. If steel wire rope isaccepted, the following to be fulfilled:

— the steel wire rope shall have at least the same breakingstrength as the stud link chain cable

— a length of chain cable shall be fitted between the anchorand the steel wire rope. The length is to be taken as thesmaller of 12.5 m and the distance between the anchor instowed position and the winch

— the anchor weight is to be increased by 25%— the length of the steel wire rope is to be at least 50% above

the table value for the chain cable— a corresponding “Memo to Owner” (MO) shall be issued.

Arrangements applying the steel wire ropes of trawl winchesmay be accepted, provided the strength of the rope is sufficient.

E 200 Materials201 The chain cable links may be made by electric resistancebutt welding (melt welding), by casting or drop forging.Shackles and swivels may be cast or forged.

The studs in stud link chain cables are to be made of cast orforged steel.

Tapered locking pins for shackle bolts are to be made of stain-less or tinned steel with a lead stopper at the thick end.

202 The materials are to be delivered with Det Norske Ver-itas' material certificates in compliance with the specificationsfor steel grades NV K1, K2 and K3.

203 Steel grade NV K1 is normally not to be used in associ-ation with H.H.P. or S.H.H.P. anchors.

204 Steel grade NV K3 is not to be used for chain diameterless than 20.5 mm.

205 Ships equipped with chain cable of steel grade NV K2 orNV K3, will have the letters s or sh, respectively, added to theequipment letter.

Table D1 Proof test load for anchorsMass of anchor

kg

Proof test load

kN

Mass of anchor

kg

Proof test oad

kN

Mass of anchor

kg

Proof test load

kN

Mass of anchor

kg

Proof test load

kN

Mass of anchor

kg

Proof test load

kN

Mass of anchor

kg

Proof test load

kN5055606570758090

100120140160180200225250275300325350375400425450475500

23.225.227.128.930.732.433.936.339.144.349.153.357.461.366.870.474.979.684.288.893.497.9103107112116

550600650700750800850900950

10001050110011501200125013001350140014501500160017001800190020002100

125132140149158166175182191199208216224231239247255262270278292307321335349362

22002300240025002600270028002900300031003200330034003500360037003800390040004100420043004400450046004700

376388401414427438450462474484495506517528537547557567577586595604613622631638

48004900500051005200530054005500560057005800590060006100620063006400650066006700680069007000720074007600

645653661669677685691699706713721728735740747754760767773779786795804818832845

78008000820084008600880090009200940096009800

100001050011000115001200012500130001350014000145001500015500160001650017000

861877892908922936949961975987999

101010401070109011101130116011801210123012601270130013301360

1750018000185001900019500200002100022000230002400025000260002700028000290003000031000320003400036000380004000042000440004600048000

13901410144014701490152015701620167017201770180018501900194019902030207021602250233024102490257026502730

DET NORSKE VERITAS


D = dc = Rule diameter of chain cables

Fig. 2Standard dimensions of stud link chain cable

DET NORSKE VERITAS


E 300 Heat treatment and material testing 301 All chain cables and accessories for chain cables, re-gardless of manufacturing process, are to be heat-treated asspecified in Table E1. When normalising, care is to be taken toensure that no links are lying on top of each other while cool-ing, and thereby delaying the cooling. A description of the heattreatment is to be given on the certificate.

302 When a manufacturer of chain cable buys material forthe links from the steel producer, he is to be instructed on theproper method of heat treatment.

303 After the chain has been heat-treated, the efficiency ofthe heat treatment is to be controlled by testing of the materialin the finished links as stated in 304 to 306.

304 From chain cables of grade NV K1 and NV K2, one setof 3 impact tests is to be taken from every four 27.5 m lengthof chain cable or from every 100 m.

The material for the testing is obtained by supplying cablelengths with extra links. The tests are to satisfy the require-ments stated in Table E1.

Subject to agreement with the Society, a reduction in thenumber of impact tests may be allowed, provided the manufac-turer by means of statistical tests data verifies that the impactrequirements in Table E1 are consistently met.

305 From chain cables of grade NV K3, one set of tests (1tensile and 6 impact tests) is to be taken from every four 27.5m length of chain or from every 100 m.

The material for the testing is obtained by supplying the cablelengths with extra links. The tensile test piece is to be takenfrom the base material opposite to the weldment. The tensiletests results are to satisfy the requirements stated in Table E1.

306 For all steel grades, 3 impact test pieces are to be takenclear of the weld (position of the test pieces, see Fig. 3). Forsteel grade K3, there are to be taken 3 additional impact testpieces from the welded zone, cut with the notch in the middleof the weld.

Impact test values of specimens taken clear of the weld are tocomply with the requirements given in Table E1. Impact testvalues (KV) for steel grade K3 of specimens taken from theweld are to be at least 50 J as average value of 3 tests when thetests are carried out at 0°C. The surveyor may also require im-pact tests from more than one length in every four.

E 400 Breaking test401 A breaking test specimen consists of at least 3 links con-nected together, and they are to be manufactured at the sametime and in the same way as the chain cable and heat-treated asthis. During the heat treatment the test specimen is to be se-curely attached to the chain cable.

402 At least one breaking test specimen is to be taken fromevery four 27.5 m lengths of chain cable or from every 100 m.For chain cables of grade NV K1 which is not heat-treated afterwelding, breaking test is to be carried out on one specimenfrom each 27.5 m length. For cast chain cables (grades NV K2and NV K3), one breaking test per heat treatment batch is to betaken, with a minimum of one for every four 27.5 m lengths.The testing may be recognized as having been passed, if frac-ture has not occured at the minimum breaking strength givenin Tables E2 and E3.

403 Other tests may replace the breaking test after agreement

with the Society.

404 Should a breaking load test fail, a further test specimenmay be taken from the same length of chain cable and tested.The test shall be considered successful if the requirements arethen satisfied.

If the retest fails, the length of chain cable concerned shall berejected. If the manufacturer so wishes, the remaining threelengths belonging to the batch may then be individually sub-jected to test at the breaking load. If one such test fails to meetthe requirements, the entire batch is rejected.

405 From each manufacturing batch (same grade, size andheat treatment batch) of 25 units or less of shackles, swivels,swivel shackles, large links and end links, and from each man-ufacturing batch of 50 units or less of Kenter shackles, one unitis to be subjected to the breaking load test. Parts tested in thisway may not to be put to further use.

The Society may waive the breaking load test if:

a) the breaking load has been demonstrated on the occasionof the approval testing of parts of the same design, and

b) the mechanical properties and the impact energy of eachmanufacturing batch are proved, and

c) the parts are subjected to suitable non-destructive testing.

E 500 Proof test

501 Each length of the chain cable is to be proof tested in amachine specially approved for that purpose, and is to with-stand the load given in Tables E2 and E3 for the type, size andgrade of steel concerned, without showing any signs of defects.All joining shackles, end shackles and swivels are to be testedwith the proof load prescribed for the chain concerned. SeeD403 for specific relaxation for anchor shackle.

502 Should a proof load test fail, the defective link(s) is (are)to be replaced, a local heat treatment according to 801 to becarried out on the new link(s) and the proof load test to be re-peated. In addition, an investigation is to be made to identifythe cause of the failure.

E 600 Tolerances

601 All required measurements are to be taken after theproof testing. The measurements are to be carried out to thesatisfaction of the surveyor.

602 The allowable manufacturing minus tolerance on the di-ameter dc of the common links is:

— for dc ≤ 40 mm : –1 mm— for 40 < dc ≤ 84 mm : – 2 mm— for 84 < dc ≤ 122 mm : – 3 mm— for dc > 122 mm: – 4 mm.

The allowable manufacturing plus tolerance is 5%. The cross-sectional area of the link is at least to be the theoretical area forthe nominal diameter.

The calculation of the theoretical area is to be based on the av-erage of four measurements of the diameter equally spacedaround the circumference.

Three links from every four 27.5 m length or every 100 mlength of chain cable are to be chosen for measurements of thediameter.

DET NORSKE VERITAS


603 The allowable manufacturing tolerance on length of 5links is + 2.5 %. The measurements are to be taken while thechain is loaded to about 10% of the proof load. Other methodsfor the measurements may be agreed upon.

604 The allowable manufacturing tolerance on other dimen-sions that are described in 602 and 603, is ± 2.5%. For commonlinks, three links from every four 27.5 m length or every 100 mlength of chain cable are to be chosen for measurements of out-side length and width.

E 700 Identification701 Every 27.5 m length of chain cable and all accessoriesare to be stamped with:

— Chain grade, according to Table E1— Certificate No.— Det Norske Veritas' stamp.

E 800 Repair of defects801 Links seriously damaged are to be replaced with shack-les of approved type and grade of steel or with new links cor-responding to the original ones as regards grade of steel andspecified properties. The use of other material and processes ofmanufacture is subject to approval in each case. Each substi-tute (new link) is to be subjected to a satisfactory method ofheat treatment (normalising, normalising and tempering orquenching and tempering) as required, without affecting adja-cent links, if the entire chain is not reheat-treated. Processes forindividual treatment of links are to be tested as to impact prop-erties (for NV K3 chain also the tensile strength) by testing ex-tra links which are manufactured and treated in the same wayas the new links in the chain.

The repaired chain length is finally to be subjected to the re-quired proof testing.

802 Defective accessories for chain cables (shackles andswivels) are to be replaced by new ones of the same grade asthe chain cable, or better.

Table E1 Heat treatment and mechanical properties

Mechanical properties:

Grade Heat treatmentNV K1 Normalised 1) NV K2 Normalised 2) NV K3 Quenched and tem-

pered, normalised or nor-malised and tempered

Yield stress REH or proof stress RP0.2 N/mm2 Minimum 295 Minimum 410Tensile strength, RM N/mm2 370 - 490 490 - 690 Minimum 690Elongation (L0 = 5d) A5 % Minimum 25 Minimum 22 Minimum 17Reduction of area, Z % minimum 40 3)

Impact values (KV), as an average of 3 tests, J minimum 27; 20 °C minimum 27; 0 °C minimum 60; 0°C1) Chain cables with diameters up to 50 mm may be supplied without heat treatment after welding, provided that a breaking test is carried out on one spec-

imen from each length, see 402.

2) Cast chain cable, grade NV K2, is to be normalised or may, at option of the manufacturer, be hardened and tempered.

3) 35% for cast links and chain accessories.

DET NORSKE VERITAS


Table E2 Test loads and mass. Stud link chain cables

Diameter of chain mm

Chain of Steel grade NV K1

Chain of Steel grade NV K2

Chain of Steel grade NV K3 Guidance

Proof test load

kN


kN

Proof test load

kN


kN

Proof test load

kN


kN

Approximate mass per m

kg

1112.51416

17.519

20.52224262830323436384042444648505254565860626466687073767881848790929597100102105107111114117120122124127130132137142147152157162

3646587689

105123140167194225257291328366406448492538585635686739794851909969

1030110011601230129013901500158016901810192020502130226023402470256027002790297031103260340035003600375039004000426045204790505053205590

516682

107127150175200237278321368417468523581640703769837908981106011401220129013801470156016601750184019902150226024102580275029203040323033503530366038603980425044404650486050005140535055705720608064506840722076007990

516682

107127150175200237278321368417468523581640703769837908981

106011401220129013801470156016601750184019902150226024102580275029203040323033503530366038603980425044404650486050005140535055705720608064506840722076007990

7292

116150179211244280332389449514583655732812896981

1080117012801370148015901710181019402060219023102450258027903010316033803610385040904260451046804940512053905570594062306510681070007200749078008000851090309560

101001064011170

7292

116150179211244280332389449514583655732812896981

1080117012801370148015901710181019402060219023102450258027903010316033803610385040904260451046804940512053905570594062306510681070007200749078008000851090309560101001064011170

102132165216256301349401476556642735833937

1050116012801400154016801810196021102270243026002770294031303300350036903990430045004820516055005840608064406690706073207700796084808890930097209990

10280107101114011420121601291013660144301520015970

3.74.45.66.88.09.3

10.612.614.817.119.622.325.128.131.334.738.241.945.849.854.058.463.067.872.777.883.188.694.2

100.0106.0115.2124.9131.6142.0152.9164.2176.0184.1196.6205.0218.5227241250269284299314326335351367378408437470500530570

DET NORSKE VERITAS


Fig. 3Position of test pieces

F. Windlass and Chain Stoppers

F 100 General design

101 The anchors are normally to be operated by a speciallydesigned windlass. For ships with length L < 50 m, one of thecargo winches may be accepted as windlass, provided the re-quirements to the arrangement and function are satisfied.

102 The windlass is to have one cable lifter for each anchorstowed in hawse pipe.

The cable lifter is normally to be connected to the driving shaftby release coupling and provided with brake.

The number of pockets in the cable lifter is not to be less than5. The pockets, including the groove width etc. are to be de-signed for the joining shackles/kenter shackles with due atten-tion to dimensional tolerances.

When the chain cable diameter is less than 26 mm, only one ofthe cable lifters need be fitted with release coupling and brake.

103 For each chain cable there is normally to be a chain stop-per, arranged between windlass and hawse pipe. The chain ca-bles are to reach the hawse pipes through the cable lifter only.

104 Electrically driven windlasses are to have a torque lim-iting device.

Electric motors are to comply with the requirements of Pt.4Ch.8.

105 The windlass with prime mover is to be able to exert thepull specified by Table F1 directly on the cable lifter. For dou-ble windlasses the requirements apply to one side at a time.

Attention is to be paid to stress concentrations in keyways andother stress raisers and also to dynamic effects due to suddenstarting or stopping of the prime mover or anchor chain.

106 The capacity of the windlass brake is to be sufficient forsafe stopping of anchor and chain cable when paying out.

The windlass with brakes engaged and release coupling disen-gaged is to be able to withstand a static pull of 45% of the chaincable minimum breaking strength given in Table E2, withoutany permanent deformation of the stressed parts and withoutbrake slip.

If a chain stopper is not fitted, the windlass is to be able towithstand a static pull equal to 80% of the minimum breakingstrength of the chain cable, without any permanent deforma-tion of the stressed parts and without brake slip.

107 Calculations indicating compliance with the require-ments in 105 and 106 may be dispensed with when completeshop test verification is to be carried out.

108 The chain stoppers and their attachments are to be ableto withstand 80% of the minimum breaking strength of thechain cable, without any permanent deformation of thestressed parts. The chain stoppers are to be so designed that ad-ditional bending of the individual link does not occur and thelinks are evenly supported. Bar type chain stoppers stoppingthe chain link from one side may be accepted after special con-sideration and provided that satisfactory strength is demon-strated by calculation or prototype test.

Guidance note:A chain stopper designed to a recognised national or internation-al standard may be accepted provided its service experience isconsidered satisfactory by the Society.


F 200 Materials

201 Cable lifter shafts and cable lifters with couplings are tobe made from materials as stated in Table F2.

202 Windlass and chain stoppers may be cast components orfabricated from plate materials. The material in cast compo-nents is to be cast steel or nodular cast iron with elongation notless than 18%. Plate material in welded parts is to be of grade

Table E3 Test loads for short link chain cablesDiameter of chain

mmProof load

kNBreaking load

kN111213

22.426.631.3

47.753.262.5

141516

36.341.647.4

72.583.294.7

171819

53.559.866.7

107.0119.5133.5

202122

73.981.489.6

147.5163.0179.0

232425

97.9106.5116.0

195.5213231

262728

125.0135.0144.5

250270289

293031

155.5166.5177.5

311333355

32333435

190.0201214227

380402428453

Table F1 Lifting powerLifting force and speed

Grade of chainK1 K2 K3

Normal lifting force for 30 min in N 36.8 dc

2 41.7 dc2 46.6 dc

2

Mean hoisting speed 9 m/min.Maximum lifting force for 2 minutes (no speed requirement) 1.5 x normal lifting force

dc = diameter of chain in mm.

Table F2 Material requirementsChain cable diame-ter ≤ 46 mm

Chain cable diame-ter > 46 mm

Cable lifters and cou-plings

Nodular cast iron or special cast iron

Cast steel

Cable lifter shaft Forged or rolled steel, cast steel

DET NORSKE VERITAS


as given in Table F3.

F 300 Testing

301 Before assembly the following parts are to be pressuretested:

— housings with covers for hydraulic motors and pumps— hydraulic pipes— valves and fittings— pressure vessels— steam cylinders.

The tests are to be carried out in accordance with Pt.4 Ch.6Sec.5 and Sec.7, and Pt.4 Ch.7. Test pressure for steam cylin-ders is to be 1.5 times the working steam pressure.

302 After completion, at least one prime mover of the wind-lass is to be shop tested with respect to required lifting forcesand if relevant, braking forces.

If calculations have not previously been accepted, shop testingof the complete windlass is to be carried out.

303 After installation of the windlass on board, an anchoringtest is to be carried out to demonstrate that the windlass withbrakes etc. functions satisfactorily.

The mean speed on the chain cable when hoisting the anchorand cable is not to be less than 9 m/min. and is to be measuredover two shots (55 m) of chain cable during the trial. The trialshould be commenced with 3 shots (82.5 m) of chain cable ful-ly submerged. Where the depth of water in trial areas is inade-quate, consideration will be given to acceptance of equivalentsimulated conditions.

G. Towlines and Mooring Lines

G 100 General

101 Steel wire ropes, are to be made by an approved manu-facturer.

102 The number, length and breaking strength of towlinesand mooring lines are given in C. Note that towlines andmooring lines are given as guidance only.

103 The strands of steel wire ropes are to be made in equallay construction (stranded in one operation), and are normallyto be divided in groups as follows:

— 6x19 Group consists of 6 strands with minimum 16 andmaximum 27 wires in each strand

— 6x36 Group consists of 6 strands with minimum 27 andmaximum 49 wires in each strand.

Fig. 4 gives examples of rope constructions. Other rope con-structions may be accepted by the Society upon special consid-eration.

Fig. 4Constructions of steel wire ropes

104 The diameter of a fibre rope is not to be less than 20 mm.

105 Synthetic fibre ropes will be specially considered withrespect to size, type, material and testing.

G 200 Materials201 Towlines and mooring lines may be of steel, natural fi-bre or synthetic fibre construction.

202 Wire for steel wire ropes is to be made by open hearth,electric furnace, LD process or by other processes specially ap-proved by the Society.

Normally, the tensile strength of the wires is to be 1570 N/mm2

or 1770 N/mm2. The wire is to be galvanised or bright (uncoat-ed). Galvanised wire is to comply with the specifications inISO Standard 2232.

203 The steel core is to be an independent wire rope. Nor-mally, the wires in a steel core are to be of similar tensilestrength to that of the main strand, but are not to be less than1570 N/mm2.

The fibre core is to be manufactured from a synthetic fibre.

204 Unless otherwise stated in the approved specification,all wire ropes are to be lubricated. The lubrications are to haveno injurious effect on the steel wires or on the fibres in therope.

G 300 Testing of steel wire ropes301 Steel wire ropes are to be tested by pulling a portion ofthe rope to destruction. The test length which is dependent onthe rope diameter, is given in Table G1. The breaking load ofthe ropes is not to be less than given in Table G2 for the di-mension concerned.

Table F3 Plate material gradesThickness in mm Normal strength

structural steelHigh strength struc-

tural steelt ≤ 20 A A

20 < t ≤ 25 B A25 < t ≤ 40 D D40 < t ≤ 50 E E

DET NORSKE VERITAS


302 If facilities are not available for pulling the completecross section of the rope to destruction, the breaking load maybe determined by testing separately 10% of all wires from eachstrand. The breaking strength of the rope is then considered tobe:

P = f t k (kN)

f = average breaking strength of one wire in kNt = total number of wiresk = lay factor as given in Table G3.

303 The following individual wire tests are to be performed:

— torsion test— reverse bend test— weight and uniformity of zink coating.

These tests are to be made in accordance with and are to com-ply with ISO Standard 2232.

G 400 Testing of natural fibre ropes401 Natural fibre ropes are, if possible, to be tested by pull-ing a piece of the rope to destruction. For qualities 1 and 2, thebreaking load is not to be less than given in Table G4.

Table G1 Test lengthsRope diameter

in mmMinimum test length

in mmd ≤ 6 300

6 < d ≤ 20 600d < 20 30 x d

Table G2 Test load and mass. Steel wire ropesConstruction

groupsNom. dia. mm

Minimum required breaking strength in kN Approximate mass kg/100 m1570 N/mm2 1770 N/mm2

FC IWRC FC IWRC FC IWRC6 x 19 group 14

1618202224262830

102133168208251299351407468

110144182224272323379440505

115150190234283337396459527

124162205253306364428496569

72.794.9120148179214251291334

82.0107135167202241283328376

6 x 19 groupand

6 x 36 group

32364044485256606468

53067182910001190140016201860

573725895

1080129015101750201022902590

59875793411301350158018302100

646817

10101220145017101980227025802920

380480593718854

100011601330

428542669810964

11301310151017101930

6 x 36 group 72768084889296

100104108112116120124128

290032303580395043304730516055906050652070207530806086009170

32703640404044504880534058106310682073607910849090809700

10330

217024202680295032403540385041804520488052505630602064306850

C = fibre core

IWRC = independent wire rope core

Table G3 Lay factor kRope construction

groupRope with FC Rope with IWRD

6 x 196 x 36

0.860.84

0.800.78

DET NORSKE VERITAS


402 If facilities are not available for making the above test,

the Society may accept testing of a specified number of theyarns from the rope. The breaking strength of the rope will thenbe deduced from these tests.

G 500 Mooring Winches

501

Guidance note:Each winch should be fitted with drum brakes the strength ofwhich is sufficient to prevent unreeling of the mooring line whenthe rope tension is equal to 80 per cent of the breaking strengthof the rope as fitted on the first layer.

Where this is achieved by the winch being fitted with a pawl andratchet or other positive locking device, then the braking mecha-nism shall be such that the winch drum can be released in con-trolled manner while the mooring line is under tension.

For powered winches the maximum hauling tension which canbe applied to the mooring line (the reeled first layer) should notbe less than 1/4.5 times the rope's breaking strength and not morethan 1/3 times the rope's breaking strength. For automatic winch-es these figures shall apply when the winch is set on the maxi-mum power with automatic control.

The rendering tension which the winch can exert on the mooringline (reeled 1st layer) should not exceed 1.5 times, nor be lessthan 1.05 times the hauling tension for that particular power set-ting of the winch on automatic control. The winch is to bemarked with the range of rope strength for which it is designed.


Table G4 Breaking loads. - natural fibre ropesCircum- ference

mm

Breaking load (approximately) in kNThree-stranded (hawser-laid)

Four-stranded (hawser-laid)

Quality 1 Quality 2 Quality 1 Quality 2647076

31.637.644.8

28.233.439.8

28.233.439.8

24.929.635.3

838995

52.059.568.0

46.353.160.5

46.052.860.2

41.147.153.6

102108114

76.485.295.4

68.075.784.7

67.075.484.7

60.267.075.2

121127140

105.1116.1139.0

93.4103.1123.5

93.2103.1123.5

82.791.6

109.6152165178

163.9190.8219.7

145.5169.4195.3

144.5169.4195.3

128.5150.5173.3

203229254

282.5353.3433.0

251.1313.9384.7

250.2318.9383.7

222.2279.0340.7

279305

520.2617.0

462.1548.2

461.5547.2

410.2486.4

DET NORSKE VERITAS


SECTION 4MASTS AND RIGGING

A. General

A 100 Introduction

101 In this section the requirements to strength and supportof masts, derrick posts and standing rigging are given.

102 The derricks and the cargo handling gear, are not subjectto approval.

A 200 Assumptions

201 The cargo handling systems are assumed only to be op-erated in harbours or in sheltered waters.

202 The formulae for determining the scantlings of stayedmasts, post and standing rigging are based on a symmetrical ar-rangement of stays and shrouds related to a vertical longitudi-nal plane through the mast or post.

Steel wire ropes for shrouds are assumed with a modulus ofelasticity equal to 7.5 x 106 N/mm2.

A 300 Definitions

301 Symbols:

P = load in t which may be lifted by the derrick ld = length of derrick in m. Where the working position of

the derrick is such that the angle between the centreline of the derrick and the horizontal always exceeds15°, ld is taken as the greatest horizontal projection ofthe derrick

ls = length of shrouds in m lm = length of mast in m from deck or top of mast house to

houndsH = height of derrick heel above deck or top of mast house

in ma = athwartship distance in m from the mast to the deck at-

tachment of shroud in question, see Fig.1c = longitudinal distance in m from the mast to the deck at-

tachment of shroud in question, see Fig.1

With reference to a transverse plane through the mast,c is to be taken negative (–) for shrouds fitted on thesame side as the derricks in question and positive (+)for those fitted on the opposite side

e = horizontal distance in m from the mast to the deck at-tachment of shroud in question, see Fig. 1.

a0, c0 and e0 refer to the shrouds nearest the transverseplane through the mast. c0 is not to be taken greaterthan B/4.

Σ = summation of:

a) Load functions for derricks simultaneously serv-ing one hatch.

b) Support functions for effective shrouds whenloads are as indicated in a), i.e. all shrouds forwardor aft of the mast whichever is opposite to thehatch in question.

c) Load functions for derricks simultaneously work-ing outboard.

d) Support functions for effective shrouds whenloads are as indicated in c), i.e. all shrouds on oneside of the ship, however the attachment to thedeck is not to exceed 0.3 B forward or aft of themast.

Fig. 1Arrangement of shrouds.

A 400 Documentation

401 The following plans and information are to be submit-ted:

— Arrangement plan showing location of mast or derrickpost, standing rigging and cargo handling gear. Informa-tion about the operation of the derrick booms, if provided,i.e. how the derricks are intended to be worked, for in-stance, if more than one derrick is intended to simultane-ously serve one hatch. Safe working load and workingposition for each provided derrick.

— Plan showing proposed scantlings of mast, derrick postand standing rigging.

— Plan showing supporting structures and strengthening ofhull in way of mast, post and standing rigging fastenings.

— Specification of the steel wire ropes intended to be usedfor standing rigging, indicating rope construction, scant-lings and minimum breaking strength.

B. Materials and Welding

B 100 Materials

101 Selection of material grades for plates and sections is tobe based on material thickness. NV-steel grades as given in Ta-ble B1 will normally be accepted.

102 The tensile strength of wire ropes intended for shroudsand stays is normally to be minimum 1570 or 1770 N/mm2 (seeTable G2 of Sec.3) and should not exceed 2200 N/mm2.

103 Material certificates for standing rigging are to be issuedby the manufacturer, confirming that the delivered productsare manufactured and tested according to the Rules (see Sec.3G) or another approved specification.

Table B1 Plate material gradesThickness

in mmNormal strength structural steel

High strength structural steel

t ≤ 20 A A20 < t ≤ 25 B A25 < t ≤ 40 D D40 < t ≤ 50 E E

DET NORSKE VERITAS


B 200 Welding201 Welding of important connections is to be carried out bywelders approved by the Society.

202 Filler metals (electrodes) for welding are to be approvedby the Society.

203 Important welds are to be inspected by radiography asrequired by the surveyor. Ultrasonic testing and magnetic-par-ticle testing may also be required.

Radiographs are generally to meet the requirements to mark 4(blue) according to «IIW Collection of Reference Radiographsof Welds». However, scattered porosity according to mark 3(green) may be accepted.

C. Arrangement and Support

C 100 Masts and posts101 Masts and posts are to be efficiently supported and con-nected to at least two decks or to one deck and a mast house topabove. If the latter arrangement is adopted, the mast house topis to be of sufficient size and adequately stiffened. A winchhouse of usual size and scantlings is not considered to meet therequirements.

C 200 Standing rigging201 The mast or post is to have at least two shrouds on eachside of the centre line of the ship. The attachment of shrouds tomast is to be carefully made so as to reduce torsional strains asfar as possible.

202 At fastenings for standing rigging and for guys and top-ping lifts, the deck is to be securely stiffened and reinforced forthe additional loading.

D. Design and Scantlings

D 100 General101 The requirements to diameter d0 and plate thickness t0for masts and posts given in the following are to be maintainedfor a distance not less than 1 m above the derrick heel fitting.Above this level, the diameter and the plate thickness may begradually reduced to 0.75 d0 and 0.75 t0 at the hounds. Mini-mum thickness is 7.5 mm.

102 Where masthead span blocks are attached to outriggers,the section modulus of the mast at the level of the outrigger isnot to be less than:

Z = 120 r Q (cm3)

r = horizontal distance in m from mast to masthead spanblocks on outrigger

Σ P = total load in t which may be lifted by the derrickson one side of the centre line of the ship

n = 1, 2, 3 etc. for single, double and triple blocks etc.,respectively.

103 Masts and posts are to be increased in thickness or rein-forced with doubling at the heel, deck and hounds.

D 200 Unstayed masts and posts with derricks201 The section modulus and moment of inertia of masts andposts with derricks are not, at decks, to be less than:

Z = 100 Σ (P l d) (cm3)

Minimum thickness of plating t = 7.5 mm.

Masts with outriggers on unusual spread will be specially con-sidered.

D 300 Stayed masts or posts with derricks with a lifting capacity not exceeding 10 t301 The outer diameter of masts or posts is not to be lessthan:

302 The plate thickness of masts or posts is not to be lessthan:

t0 = 0.014 d0 mm, minimum 7.5 mm

303 The moment of inertia of masts or posts is not to be lessthan:

α = 0.5 for derricks with a lifting capacity of 5 t or less = 1.0 for derricks with a lifting capacity of 10 t. Between

5 and 10 t, α is determined by linear interpolation.

f =

V = breaking strength of shrouds in Nq = tensile strength of shrouds in N/mm2.

D 400 Stayed masts of posts with derricks with a lifting capacity of 10 t or more, but not exceeding 40 t401 The required outer diameter d0 in mm of masts or posts,measured at deck or top of mast house, is determined from theexpression:

t0 = plate thickness of mast in mm at diameter d0F = the greater of:

402 The plate thickness of masts or posts is in no place to beless than 7.5 mm.

403 The moment of inertia of masts or posts is not to be lessthan:

G = the smaller of

Q PP∑

n---------- 1

ld

lm H–---------------

2+ (t)+∑=

I 240lm

2

lm H–--------------- Pld( ) (cm

4 )∑=

d0 140 Pld( )13---

(mm)∑=

I 240lm

2

lm H–--------------- Pld( ) 1500lm

3 fc2

ls3

------α (cm4 )∑–∑=

V100q------------ (cm

2 )

d0t0

100---------- 1.5 P 10lm

2F +∑≥

fc

ls3

------ and 12--- f 1.7a c+( )

ls3

---------------------------∑∑

I 240lm

2

lm H–--------------- Pld 1500lm

3G (cm

4 )–∑=

fc2

ls3

------ and 14--- f 1.7a c+( )2

ls3

------------------------------∑∑

DET NORSKE VERITAS


404 Section modulus of masts is in general not to be lessthan:

G = as defined in 403.

405 Where derricks are fitted both forward and aft of themast, the section modulus is further not to be less than:

K =

Σ P1 l d1 and Σ P2 l d2 refer to derricks on either side of a trans-verse plane through the mast.

Σ P1 l d1 is to be the smaller of these products.

D 500 Stayed masts without derricks501 The diameter of stayed masts without derricks is not to

be less than:

d1 = 0.75 d0 (mm)

d0 and d1 are the diameter at deck and hounds respectively.

l m1 = length of mast in m measured from deck to hounds.

502 The plate thickness is not to be less than:

t = 2.5 + 0.35 l m1 (mm)

D 600 Shrouds

601 Shrouds for masts or posts with derricks are to havebreaking strength not less than:

Permanent centre line stays may be included in Σ e when rele-vant.

602 Shrouds for masts without derricks are to have circum-ference of steel wire rope not less than 63 mm.

Z80lm

lm H–--------------- Pld

30000lm3

d0-----------------------G (cm

3 ) –∑=

Z80lm

lm H–--------------- Pld

Klm3

d0------------

fa2

lm3

--------∑ (cm3 ) –∑=

24000 1 0.25P1ld1∑

P2ld2∑--------------------+

d0

100lm1

3----------------- (mm)=

V10.8g0lm

Pld∑

lm H–( ) 1c0

B-----+

e∑

---------------------------------------------------- ((kN)=

DET NORSKE VERITAS


SECTION 5SEATS FOR ADDITIONAL LIFTING, TOWING OR MOORING EQUIPMENT

A. Crane Pedestals and Miscellaneous Lifting Posts

A 100 Introduction

101 In this subsection the requirements for strength and sup-port of crane pedestals, support of davits, A-frames and otherlifting posts are given. The requirements are enforced for safeworking load (SWL) > 30 kN or resulting bending moment onseat > 100 kNm.

102 The crane including pedestal flange and bolts or the lift-ing gear itself is not subject to approval, unless class notationCRANE, DSV or Crane Vessel is requested.

Guidance note:If ILO certification of lifting appliances is requested and DNV isto issue the certificate, approval of documentation will be re-quired. See Rules for Certification of Lifting Appliances.


A 200 Documentation

201 The following plans and information are to be submit-ted:

Plans:

— arrangement— pedestal/post with scantlings and grades of material— hull reinforcements.

For cranes on rails, also:

— support of rails— end buffers— parking position with locking arrangement and hull rein-

forcements.

Information:

— SWL— weight and weight moment of installation, in various lift-

ing positions.

For crane to be used offshore, also:

— dynamic coefficient on working load— intended sea state for operation.

A 300 Materials and welding

301 For pedestal/posts to be used in harbour only, selectionof material grade for plates and sections is to be based on TableB1 of Sec.4.

302 When intended for offshore use, the selection of materi-als is to be based on the Rules for Certification of Lifting Ap-pliances.

The design temperature TD, for determination of the impacttest temperature, is to be taken not less than –20°C, if not oth-erwise specified.

303 When a pedestal subjected to bending is not slottedthrough a deck plating with t > 10 mm, the following applies:

— either Z-quality material (Pt.2 Ch.2 Sec.1 E400) is to beused in the deck plating

— or an ultrasonic lamination test after the welding has beencompleted, is to be carried out in tension exposed areas.

A 400 Arrangement

401 For large loads see Fig.1 and Fig.2.

Fig. 1Not recommended support.

Fig. 2Recommended support.

A 500 Design loads501 For operation of crane or lifting gear in harbour SWL tobe multiplied by a dynamic coefficient 1.3, if not otherwisespecified.

502 For cranes and lifting gears for offshore use, the follow-ing is to be taken into account:

— The dynamic coefficient on SWL, specified by designerand checked against the minimum values of the Rules forCertification of Lifting Appliances.

— Vertical and horizontal accelerations for the specified seastate. av, at and al to be taken as a safe fraction of the ex-treme values given in Ch.1 Sec.4 B. Accelerations to becombined as indicated for deck equipment in Ch.1 Sec.4C500.

Guidance note:When the significant wave height HS is known,

CW23---HS=

DET NORSKE VERITAS


may be inserted in the formulae of Ch.1 Sec.4 B.

- Wind forces for the specified wind velocity, according to theRules for Certification of Lifting Appliances.


503 When the transit condition is considered critical, the de-sign loads are to be taken as given for idle deck equipment inCh.1 Sec.4 C500.

For non-compact units wind and icing are to be taken into ac-count as appropriate.

Standard ice load for North Sea winter conditions may be takenas 5 cm ice deposit on wind and weather exposed surfaces.

504 For survival craft davits, the dynamic coefficient is to betaken as 2.2.

505 For man-overboard boats, davits to withstand a horizon-tal towing force.

A 600 Allowable stresses

601 Allowable stresses in structural steel elements will inprinciple be:

when elastic analysis is applied. Yield limit for high strengthsteel is to be taken as 235 f1, unless a fatigue control is carriedout. For definition of f1 see Ch.1 Sec.2.

k = 1.0 for davit supports made of high tensile steel = 0.85 for davit supports made of mild steel.

In cases of combined stresses, the equivalent stress (vonMises) is to be applied for the yield control.

Guidance note:For lifting operation in harbour supported by a single girder inlifting direction the following simplified calculation proceduremay be applied (see Fig. 3):

Total load: P = 1.3 SWL + crane weightCrane moment:M = 1.3 MSWL + Mweight

Shear force diagrams as induced by P and M are given in Fig. 3.

Total shear forces given by:

Left side of crane:

Right side of crane:

Maximum bending moments:

Left side:

Right side:

Required shear area:

Required section modulus:


An appropriate moment of inertia is left to designers discre-tion.

Guidance note:Buckling strength requirements for circular columns will usuallybe satisfied when thickness ≥ 0.01 x diameter.


Fig. 3Crane support girder.

B. Seatings for Winches, Windlasses and other Pulling Accessories

B 100 Introduction.101 In this subsection requirements for seatings for pulling,towing and mooring equipment in general are given. Thisequipment is usually not subject to classification, unless inconnection with an additional class notation (i.e. towing equip-ment for tugs).

102 Seatings for bow anchor equipment has been dealt within Sec.3 B.

B 200 Documentation201 When breaking load of wire or chain is > 150 kN, thefollowing plans and information are to be submitted:

Plans:

— arrangement, indicating

— location of brake, motor and any wire pin or chainstopper

— top or bottom entrance of wire to drum

— seating, with quality of materials

σa or τayield or buckling limit( )

1.5k---------------------------------------------------------- any hull stresses( )

1.5--------------------------------------------–=

QlMl

----- bPl

------+=

QrMl

----- aPl

------+=

Ml Ql ad2---–

=

Mr Qr bd2---–

=

AQl or Qr

τa--------------------=

ZMl or Mr

σa----------------------=

DET NORSKE VERITAS


— hull reinforcements.

Information:

— design loads.

B 300 Design loads301 Design loads were dealt with for

— bow anchor windlasses and chain stoppers in Sec.3 F— mooring winches in Sec.3 G.

302 In general the following may have to be considered:

With motor in action:

— rated motor moment— SWL x dynamic coefficient (for lifting devices) or maxi-

mum pulling force.

With brake in action:

— 1.5 x brake moment / 1.5 x brake holding force on first lay-er, based on standard friction coefficient 0.3

— 80 % of breaking load for a mooring, or towing wire/chainwhen no pin/stopper

— 45 % when a wire pin or chain stopper is fitted.

With pin or stopper in action:

— 80 % of breaking load of wire/chain.

B 400 Calculation of stresses

401

Guidance note:A wire force will oscillate between drum bearings, whereas themoment will be held at the motor or brake end, whichever is inaction, and carried to their respective seatings.


B 500 Allowable stresses. Materials

501 Allowable stresses in structural steel will be as for liftingequipment, A600. Grades of material will be considered.

502 Materials of elements to be welded to the deck are pref-erably to be of ship quality steel of the same strength group asthe deck itself. Deck doublers to be avoided if tension perpen-dicular to deck occurs. When deck plating is subjected to ten-sion in the thickness direction, either z-quality material (Pt.2Ch.2 Sec.1 E400) or a lamination test after finished weldingmay be required. Full penetration welds may be considered.

DET NORSKE VERITAS


SECTION 6OPENINGS AND CLOSING APPLIANCES

A. General

A 100 Application

101 In this section the requirements for the arrangement ofopenings and closing appliances have been collected. The clos-ing appliances are in general to have strength at least corre-sponding to the required strength of that part of the hull inwhich they are fitted.

102 This section applies to all ships above 24 m in length,with the following exceptions:

— pleasure yachts not engaged in trade— fishing vessels, see Pt.5 Ch.6 Sec.6.

For ships less than 24 m in length this section applies as prac-ticable.

A 200 Definitions

201 Symbols:

L = rule length in m 1)

B = rule breadth in m 1)

CB = rule block coefficient 1)

t = plate thickness in mm. 1)

Z = rule section modulus in cm3 of stiffeners and simplegirders

ka = correction factor for aspect ratio of plate field = (1.1 – 0.25 s/ l)2

= maximum 1.0 for s/ l = 0.4 = minimum 0.72 for s/ l = 1.0s = stiffener spacing in m, measured along the platingl = stiffener span in m, measured along the topflange of

the member. For definition of span point, see Ch.1Sec.3 C100. For curved stiffeners l may be taken as thecord length

S = girder span in m. For definition of span point, see Ch.1Sec.3 C100

f1 = material factor = 1.0 for NV-NS steel 2)

= 1.08 for NV-27 steel 2)




wk = section modulus correction factor in tanks, see Ch.1Sec.3 C1004.

σ = nominal allowable bending stress in N/mm2 due to lat-eral pressure

τ = nominal allowable shear stress in N/mm2 due to lateralloads

p = design pressure in kN/m2 as given for the variousstructures.

1) See Ch.1 Sec.1 B.

2) For details see Ch.1 Sec.2 B and C.

202 Terms

Position

For the purpose of the Regulations, two positions of hatch-ways, doorways and ventilators are defined as follows:

Position 1 - Upon exposed freeboard and raised quarterdecks, and upon exposed superstructure deckssituated forward of a point located a quarter ofthe ship's length from the forward perpendicu-lar.

Position 2 - Upon exposed superstructure decks situatedabaft a quarter of the ship's length from the for-ward perpendicular.

(ICLL Reg.13)

Freeboards greater than minimum

Where freeboards are required to be increased, because of suchconsideration as strength, location of shell or side scuttles orother reasons, then:

a) The height of doors sills, hatchway coamings, sills of ma-chinery space openings, miscellaneous openings, ventila-tors and air pipes

b) the scantlings of hatch covers

c) freeing arrangements and means for protection of crew

d) windows and side scuttles

on the actual freeboard deck may be as required for a super-structure deck, provided the summer freeboard is such that theresulting draught will not be greater than that corresponding tothe minimum freeboard calculated from an assumed freeboarddeck situated at a distance equal to a standard superstructureheight below the actual freeboard deck. Similar considerationsmay be given in cases of draught limitation on account of bowheight.

Ship types

The basic ship types are as follows:

Type "A" Ships designed solely for the carriage ofliquid cargo

Type "B" Cargo ship other than "A", with steelweathertight hatch covers

Type "B-100" "B-60"Cargo ship of type "B" with reducedfreeboard on account of their ability tosurvive damage

Type "B+" Cargo ship with increased freeboard onaccount of hatch cover arrangement

Weathertight means that in any sea condition water will notpenetrate into the vessel.

Watertight means capable of preventing the passage of waterthrough the structure under a head of water for which the sur-rounding structure is designed.

Freeboard, freeboard deck and superstructure, see Ch.1 Sec.1B200.

A 300 Documentation301 The following plans covering items treated in this sec-tion are normally to be submitted for approval:

Arrangement and design of:

— small hatches and manholes— watertight hatches— watertight doors— weathertight doors— ventilators— side scuttles, windows— freeing ports— cargo hatchway with covers and securing appliances— horizontal stopper arrangement for hatch covers— doors in side shell, bow and stern with securing appliances— tank access, ullage and ventilation openings— scuppers and sanitary discharges

DET NORSKE VERITAS


— air pipes above deck with vent heads— engine room skylights and their closing appliances.

Each item should be easily identifiable in the drawing with re-spect to make, size, position and type (function). Several ofthese items are covered by the freeboard plan as required in302.

302 Freeboard plan

A freeboard plan, covering the arrangement and design of thefollowing items treated in this section, is to be submitted forapproval:

— doors— side scuttles and windows— hatches— ventilators— air pipes— scuppers, sanitary discharges and garbage chutes— sea inlets and outlets in connection with unmanned ma-

chinery space— freeing arrangements— guard rails and bulwarks— gangway, passageway, under deck passage and life line— timber deck cargo fittings— doors in side shell, bow and stern.

303 An operating and maintenance manual for the side shell,bow and stern doors is to be provided on board and containnecessary information on:

— main particulars and design drawings— service conditions, e.g. service restrictions, emergency op-

erations, acceptable clearances for supports— maintenance and function testing— register of inspections and repairs.

The manual is to be submitted for approval limited to the itemsgiven in Pt.5 Ch.2 Sec.3 A301 c).

Guidance note:It is recommended that recorded inspections of the door support-ing and securing devices be carried out by the ship's staff atmonthly intervals or following incidents that could result in dam-age, including heavy weather or contact in the region of side shellor stern doors.Any damage recorded during such inspections is tobe reported to the Society.


304 Documented operating procedures for closing and se-curing of side shell, bow and stern doors are to be kept onboard and posted at the appropriate places.

A 400 Testing

401 All weathertight/watertight doors and hatch covers areto be function tested.

402 For ships exclusively intended for the carriage of con-tainers in the cargo holds, for which an exemption to the ICLL,Reg.16 (see E and F) has been granted by the Flag Administra-tion, and which complies with the requirements given in Pt.5Ch.2 Sec.6 K, the required testing for weathertightness givenin Ch.1 Sec.1 D may be dispensed with.

403 If non weathertight hatch covers are fitted in accordancewith 402, this will be noted in the main letter of approval withthe implication that hose testing for weathertightness in ac-cordance with Ch.1 Sec.1 D will not be carried out.

B. Access Openings in Superstructures and Freeboard Deck

B 100 Doors101

1) All access openings in bulkheads at ends of enclosed su-perstructures shall be fitted with doors of steel or otherequivalent material, permanently and strongly attached tothe bulkhead, and framed, stiffened and fitted so that thewhole structure is of equivalent strength to the unpiercedbulkhead and weathertight when closed. The means for se-curing these doors weathertight shall consist of gasketsand clamping devices or other equivalent means and shallbe permanently attached to the bulkhead or to the doorsthemselves, and the doors shall be so arranged that theycan be operated from both sides of the bulkhead.

2) Except as otherwise provided in these Regulations, theheight of the sills of access openings in bulkheads at endsof enclosed superstructures shall be at least 380 millime-tres above the deck.

(ICLL Reg.12)

102

a) Doors should generally open outwards to provide addi-tional security against the impact of the sea. Doors whichopen inwards are to be especially approved.

b) Portable sills should be avoided. However, in order to fa-cilitate the loading/unloading of heavy spare parts or sim-ilar, portable sills may be fitted on the followingconditions:

i) They must be installed before the ship leaves port.

ii) Sills are to be gasketed and fastened by closely spacedthrough bolts.

iii) Whenever the sills are replaced after removal, theweathertightness of the sills and the related doorsmust be verified by hose testing. The dates of removal,replacing and hose testing shall be recorded in theship's log book.

(IACS LL5)

103 Weathertight doors as specified above are to be fitted inall access openings in:

— bulkheads at ends of superstructures— bulkheads of deckhouses on freeboard deck protecting

openings in the freeboard deck— companionways on freeboard deck and superstructure

deck— bulkheads of deckhouses on superstructure deck protect-

ing openings in the superstructure deck— companionways and bulkheads of deckhouse upon anoth-

er deckhouse on freeboard deck protecting openings in thefreeboard deck.

B 200 Sill heights201 Openings as mentioned in 100 are in general to have sillheights not less than 380 mm.

The following openings in position 1 are to have sill heightsnot less than 600 mm:

— Companionways— where access is not provided from the deck above: Open-

ings in poop frontbulkhead, bulkheads at ends of midshipssuperstructures and bulkheads at ends and sides of deck-houses

— openings in forecastle end bulkhead covering entrance tospace below the deck

DET NORSKE VERITAS


— openings in engine casings.

202 In ships which have their freeboard assignment basedupon a flooding calculation (type «A», «B-60» or «B-100»),the sill heights for the superstructure bulkhead openings mayrequire to be adjusted according to the calculated damage wa-terline. In such ships were engine casings are not protected byouter structures, two weathertight doors in series are required,the sill height of the inner door shall not be less than 230 mm.

203 Openings which are used only when the ship is in har-bour (for handling of spare parts, etc.), may have a reduced sillheight.

204 For vessels trading in domestic waters reduced sillheight may be accepted in accordance with Pt.1 Ch.1 Sec.2 B900.

B 300 Access openings in freeboard and superstructure decks

301 Manholes and flush scuttles in position 1 or 2 or withinsuperstructures other than enclosed superstructures shall beclosed by substantial covers capable of being made watertight.Unless secured by closely spaced bolts, the covers shall be per-manently attached.

302 Openings in freeboard decks other than hatchways, ma-chinery space openings, manholes and flush scuttles shall beprotected by an enclosed superstructure, or by a deckhouse orcompanionway of equivalent strength and weathertightness.Any such opening in an exposed superstructure deck or in thetop of a deckhouse on the freeboard deck which gives accessto a space below the freeboard deck or a space within an en-closed superstructure shall be protected by an efficient deck-house or companionway. Doorways in such deckhouses orcompanionways shall be fitted with doors complying with therequirements of 101.

303 In position 1 the height above the deck of sills to thedoorways in companionways shall be at least 600 millimetres.In position 2 it shall be at least 380 millimetres.

(ICLL Reg.18)

304 Regarding the requirement to protect openings in super-structures (302) it is considered that openings in the top of adeckhouse on a raised quarterdeck having a height equal to orgreater than a standard height raised quarterdeck are to be pro-vided with an acceptable means of closing but need not be pro-tected by an efficient deckhouse or companionway as definedin the regulation provided the height of the deckhouse is atleast the height of a full superstructure.

(IACS LL46)

305 Only those doorways in deckhouses leading to or givingaccess to companionways leading below, need to be fitted withdoors in accordance with 101.

Alternatively, if stairways within a deckhouse are enclosedwithin properly constructed companionways fitted with doorscomplying with 101, the external doors need not be weather-tight.

Where an opening in a superstructure deck or in the top of adeckhouse on the freeboard deck which gives access to a spacebelow the freeboard deck or to a space within an enclosed su-perstructure is protected by a deckhouse, then it is consideredthat only those side scuttles fitted in spaces which give directaccess to an open stairway need be fitted with deadlights in ac-cordance with L100. A cabin is considered to provide adequateprotection against the minimal amount of water which will en-ter through a broken side scuttle glass fitted on the second tier.

In the application of 301 and 302 it is understood that:

i) Where access is provided from the deck above as an alter-native to access from the freeboard then the height of sills

into a bridge or poop should be 380 mm. The same consid-eration should apply to deckhouses on the freeboard deck.

ii) Where access is not provided from above the height of thesills to doorways in a poop bridge or deckhouse on thefreeboard deck should be 600 mm.

iii) Where the closing appliances of access openings in super-structures and deckhouses are not in accordance with 101,interior deck openings are to be considered exposed, i.e.situated in the open deck.

(IACS LL8)

C. Side and Stern Doors

C 100 General.101 These requirements cover cargo and service doors in theship side (abaft the collision bulkhead) and stern area, belowthe freeboard deck and in enclosed superstructures. For re-quirements for bow doors, see Pt.5 Ch.2 Sec.3.

102 The side and stern doors are to be fitted as to ensuretightness and structural integrity commensurate with their lo-cation and the surrounding structure.

The number of such openings shall be the minimum compati-ble with the design and proper working of the ship.

103 Where the sill of any cargo or service door is above theuppermost loadline, special consideration is to be given to pre-venting the spread of any leakage water over the deck. A flat-bar welded to the deck and provision of scuppers would be anacceptable arrangement.

104 Where the sill of any cargo or service door is below theuppermost load line, the arrangements will require to be spe-cially considered to ascertain that the safety of the ship is in noway impaired. It is considered that the fitting of a second doorof equivalent strength and watertightness is one acceptable ar-rangement. In that case leakage detection device should beprovided in the compartment between the two doors. Further,drainage of this compartment to the bilges controlled by aneasily accessible screw down valve, should be arranged. Theouter door should preferably open outwards.

(IACS LL21)

105 Doors should preferably open outwards.

106 Terms:

Cleats: Devices for pre-compression of packings and steel tosteel contact.

Supports: Load carrying devices designed for transfer of act-ing forces from door structures to hull structures.

Locking arrangement: Preventive measures ensuring thatcleats and supports as applicable always remain in positionwhen engaged.

C 200 Structural arrangement201 Door openings in the shell are to have well rounded cor-ners and adequate compensation is to be arranged with webframes at sides and stringers or equivalent above and below.

202 Doors are to be adequately stiffened, and means is to beprovided to prevent movement of the doors when closed. Ad-equate strength is to be provided in the connections of the lift-ing/manoeuvring arms and hinges to the doors structures andto the ship structure.

203 A ≥ 12 m2 Doors with light opening area are to be suchthat the sea pressure is transferred directly to the hull coam-ings.

204 For doors with light opening area A < 12 m2 securingbolts or similar devices may be accepted as carriers of sea pres-

DET NORSKE VERITAS


sure to the coamings, if an arrangement as required in 203 isnot feasible.

205 If a door is divided into separate sections, each section isto have full strength independent of the other sections.

206 Where doors also serve as vehicle ramps, the design ofthe hinges should take into account the ship angle of trim andheel, which may result in uneven loading on the hinges.

C 300 Design loads

301 The design sea pressure is given by:

p = ( pdp – (4 + 0.2 ks) h0 ) 1)

minimum 6.25 + 0.025 L (kN/m2)

pdp, ks = as given in Ch.1 Sec.4 C201h0 = vertical distance in m from the load point to the wa-

terline at draught T.

1) For ships with service restrictions p may be reduced with the percentagesgiven in Ch.1 Sec.4 B202. CW should not be reduced.

302 The design force for securing bolts and other closing de-vices, supporting members and surrounding structure is givenby:

F1 = A pe 103 + FP (N)

or

F2 = F0 + 10 W + FP (N)

F1 is applicable for ports opening inwards.

F2 is applicable for ports opening outwards.

pe = external design pressure p according to 301, minimum25kN/m2.

FP = total packing force in NF0 = FCthe greater of and 5000 A (N)FC = accidental force (N) due to loose cargo etc., to be uni-

formly distributed over the area A and not to be takenless than 300 000 N.

For small doors such as bunker doors and pilot doors,the value of FC may be appropriately reduced. Howev-er, the value of FC may be taken as zero, provided anadditional structure such as an inner rampway is fitted,which is capable of protecting the door from accidentalforces due to loose cargo etc.

A = area of door opening (m2) to be determined on the ba-sis of the loaded area taking account of the direction ofthe pressure

W = mass of door (kg).

pe is normally to be calculated at the midpoint of A.

Packing force is to be decided depending on type and hardnessof packing. For calculation purpose, however, the packing linepressure should not be taken less than 5 N/mm. The packingline pressure is to be specified.

C 400 Plating

401 The thickness requirement corresponding to lateral pres-sure is given by:

p = as given in 300.

The thickness is in no case to be less than the minimum shellplate thickness.

402 Where doors also serve as vehicle ramps, the plating isnot to be less than required for vehicle decks.

C 500 Stiffeners501 The section modulus requirement is given by:

assuming simply supported ends.

p = as given in 300

502 The stiffener web plate at the ends is to have a net sec-tional area not less than:

A = 0.08 l s p (cm2)

p = as given in 300.

503 Edge stiffeners of doors are to have a moment of inertianot less than:

I = 8 pl d4 (cm4)

for cover edges connected to a rigid ship structure member oradjacent door coaming.

d = distance between closing devices in mpl = packing line pressure along edges in N/mm, see 302.

504 For edge stiffeners supporting main door stiffeners be-tween securing devices, the moment of inertia is to be in-creased corresponding to the extra force.

505 Where doors also serve as vehicle ramps, the stiffenerscantlings are not to be less than required for vehicle decks.

C 600 Girders601 The section modulus requirement for simple girders as-suming simply supported ends is given by:

S = girder span in mb = loading breadth in mp = design pressure according to 300.

602 The web area requirement (after deduction of cut-outs)at the girder ends is given by:

S, b and p as in 601.

603 For large doors with a grillage girder system, a directstress analysis as outlined in Ch.1 Sec.12 may be necessary.Design loads are to be as given in 300, and the allowablestresses are as follows:

— bending or normal stress:

s = 120 f1 N/mm2

— Shear stress:

τ = 80 f1 N/mm2

— Equivalent stress:

The material factor f1 is not to be taken greater than 1.39 unlessa direct stress analysis with regard to relevant modes of failures(e.g. fatigue) is carried out.

604 The webs of girders and stringers are to be adequately

t1.58ka s p

f1

----------------------------- (mm)=

Z0.8 l

2s p

f1--------------------- (cm

3)=

Z1.05 S

2b p

f1--------------------------- (cm

3)=

A0.08 S b p

f1------------------------- (cm

2)=

σe σ23τ2

+ 150 f1 N mm2⁄= =

DET NORSKE VERITAS


stiffened, preferably in a direction perpendidular to the shellplating.

605 The girder system is to be given sufficient stiffness toensure integrity of the boundary support of the door. Edgegirders should be adequately stiffened against rotation and areto have a moment of inertia not less than:

I = 8 pl d4 (cm4)

d = distance between closing devices in mpl = packing line pressure in N/mm, see 302.

For edge girders supporting main door girders between secur-ing devices, the moment of inertia is to be increased in relationto the additional force.

C 700 Closing arrangement, general

701 Closing devices are to be simple to operate and easily ac-cessible. Where hinges are used as closing devices they shouldbe well integrated into the door structure.

702 Packing material is to be of a comparatively soft type,and the supporting forces are to be carried by the steel structureonly. Other types of packing will be specially considered.

703 Flat bars or similar fastening devices for packings are tohave scantlings and welds determined with ample considera-tions to wear and tear.

704 Devices are to be arranged for the doors to be secured inopen position.

C 800 Closing arrangement, strength

801 Side and stern doors are to be fitted with adequate meansof closing and securing, commensurate with the strength of thesurrounding structure.

802 The closing and/or supporting devices are to be fitted notmore than 2.5 metres apart and as close to corners as possible.The number of devices are generally to be the minimum prac-tical whilst taking into account the requirement for redundantprovision given in 806 and the available space for adequatesupport in the surrounding hull structure which may limit thesize of each device.

803 Only supports having an effective stiffness in a given di-rection are to be included in a calculation of the load carryingcapacity of the devices. The total external or internal force, asgiven in 302, may normally be considered as equally distribut-ed between the devices. However, the distribution of the totalforces acting on the supports may, for doors with a complexclosing arrangement, be required calculated by a direct calcu-lation taking into account the flexibility of the door and sur-rounding hull structure and the position of the supports.Maximum design clearance for effective supports should nor-mally not exceed 3 mm. Design clearances are to be includedin the Operating and Maintenance Manual as given in A302.Allowable normal, shear and equivalent stresses in closing andsupporting elements are as given in 603.

804 The nominal tensile stress in way of threads of bolts isnot to exceed 105 f1 N/mm2. The arrangement of securing andsupporting devices is to be such that threaded bolts do not carrysupport forces.

805 For steel to steel bearings in closing and supporting de-vices, the nominal bearing pressure calculated by dividing thedesign force by the projected area is not to exceed 0.8σf, whereσf is the yield stress of the bearing material. For other bearingmaterials, the permissible bearing pressure is to be determinedaccording to the manufacturer's specification.

806 For side and stern doors effective supports includingsurrounding door and hull structural members are, in the caseof failure of any single support, to have sufficient capacity towithstand the total design forces.In this case the allowablestresses as given in 603 may be increased by 20%.

807 All load transmitting elements in the design load path,from the door through securing and supporting devices into theship structure, including welded connections, are to be to thesame strength standard as required for the securing and sup-porting devices.

C 900 Closing arrangement, system for operation and indication/monitoring

901 Cleats and support devices are to be equipped with me-chanical locking arrangement (self locking or separate ar-rangement) or to be of the gravity type.

902 Where hydraulic operating systems are applied, cleatsand support devices are to remain locked in closed position incase of failure in the hydraulic system.

903 Systems for opening and closing of the door, operationof cleats and support devices and, where applicable, for lock-ing arrangement are to be interlocked in such a way that theycan only operate in the proper sequence. Hydraulic operatingsystems are to be isolated from other circuits and to be blockedwhen doors and closing arrangement are in closed/locked po-sition.

904 Signboards giving instructions to the effect that thedoors are to be closed and all the closing devices locked beforeleaving quay side (or terminal), are to be placed at the operat-ing panel (or for small doors at the door when no operatingpanel) and on the bridge, and are to be supplemented by warn-ing indicator lights on the panel and on the bridge.

905 Doors with clear opening area greater than 6 m2 are tobe provided with an arrangement for remote control, from aconvenient position above the freeboard deck, of:

— the closing and opening of the doors— associated cleats, support and locking devices.

For doors which are required to be equipped with a remotecontrol arrangement, the open/closed position of the door andevery closing decive (cleats, support and locking device) is tobe indicated at the remote control station.

The operating panel for remote controlled doors is to be inac-cessible to unauthorised persons.

906 The requirements given in 907 to 911 apply to doors inthe boundary of special category spaces or ro-ro spaces, as de-fined in Ch.1 Sec.10, through which such spaces may be flood-ed.

For cargo ships, where no part of the door is below the upper-most waterline and the area of the door opening is not greaterthan 6 m2, then the requirements in 907 to 911 need not be ap-plied.

907 Separate indicator lights are to be provided on each op-erating panel to indicate that the doors are closed and that theircleats, support and locking devices as applicable are properlypositioned.

Indication panels are to be provided with a lamp test function.

908 Separate indicator lights and audible alarms are to beprovided on the navigation bridge to show and monitor thatany of the doors are properly positioned and that cleats, sup-port and locking devices as applicable are properly positioned.

The indication panel on the navigation bridge is to be equippedwith a mode selection function "harbour/sea voyage", so ar-ranged that audible alarm is given if the vessel leaves quay side(or terminal) with side shell or stern doors not closed or withany of the cleats, support and locking devices, as applicable,not in the correct position.

When the mechanical lock is placed inside the hydraulic cylin-der moving the cleat, and this is non-duplicated, indication ofthe open/closed position of any of the cleats, support and lock-ing device is to be made on the lock inside the cylinder.

DET NORSKE VERITAS


909 The indicator and alarm system on the navigation bridgeis to be designed on the fail to safe principle. The panel is to beprovided with a function test facility and a separate alarm forpower failure to the indicator lights and audible alarm system.

910 The power supply for indicator and alarm systems is tobe independent of the power supply for the operating and clos-ing arrangements and is to be provided with a backup powersupply. It shall not be possible to turn off the indicator lights.

Sensors for the indicator system are to be protected from water,ice formation and mechanical damage.

911 For passenger ships, a water leakage detection systemwith audible alarm and television surveillance is to be arrangedto provide an indication to the navigation bridge and to the en-gine control room of any leakage through the doors.

For cargo ships, a water leakage detection system with audiblealarm is to be arranged to provide an indication to the naviga-tion bridge.

D. Hatchway Coamings

D 100 General101 Side coamings of hatchways are to extend to lower edgeof deck beams. Side coamings not forming part of continuousgirders, are below deck to extend two frame spaces beyond thehatch ends.

102 Hatch end coamings not in line with ordinary deck trans-verses are below deck to extend at least three longitudinalframe spaces beyond the side coamings.

103 Continuous hatchway coamings on strength deck are tobe made from steel of the same strength group as the deck plat-ing. The same apply to non-continuous coamings effectivelysupported by longitudinal strength member or being an effec-tive part of the deck girder system.

104 If the junction of hatch coamings forms a sharp corner,well rounded brackets are to be fitted towards the deck bothlongitudinally and transversely. The longitudinal brackets areto be welded by full penetration welding.

The hatch end beam is to be given a smooth transition to thedeck transverse.

If the hatch end beam is replaced by a stool tank, this is to bein line with structures outside the hatch.

105 The web plate of low hatch side coamings is to be stiff-ened over the entire height at each frame or with a stiffenerspacing of about 60 x web thickness. Tripping brackets are tobe fitted on every 2nd frame.

106 Cut-outs in the top of hatch coamings are normally to beavoided. Unavoidable cut-outs are to be circular or elliptical inshape. Local reinforcements should be given a soft transitionin the longitudinal direction.

Unavoidable cutouts in longitudinal coaming end brackets areto be as small as possible and with edge reinforcement.

D 200 Coaming heights201 The minimum height of coamings for hatches withweathertight covers is normally not to be less than:

600 mm in position 1

450 mm in position 2

202 Manholes and small scuttles with coaming height lessthan given in 201, and flush scuttles may be allowed when theyare closed by substantial watertight covers. Unless secured byclosely spaced bolts, the covers are to be permanently attached.

203 Coamings with heights less than given in 201 may be ac-cepted after special consideration of arrangement and integrityof the vessel. When such acceptance is given, the stiffness of

deck girders supporting the covers is given by the following re-quirement to moment of inertia:

p = design pressure for deck girder in kN/m2 as given inE200

b = breadth in m of load area for deck girderl = total length in m of hatch coaming between supportsn = number of cover elements along length l of coaming.

204 Coamings with increased height may be required onships of «type B-100» and «B-60» if found necessary by thefloatability calculation.

D 300 Scantlings301 Hatchway coamings to holds also intended to carry wa-ter ballast or oil in bulk, are to satisfy the requirements for tankbulkheads given in Ch.1 Sec.9.

302 The scantlings of coamings acting as deck girders are tosatisfy the requirements in Ch.1 Sec.8.

303 For hatches with area larger than 12.0 m2, the platethickness of hatchway coamings on weather deck is not to beless than 11 mm. For hatches with area less or equal to 12.0 m2,the plate thickness of the hatchway coamings on weather deckis not to be less than 9.0 mm.

304 Hatchway coamings of conventional design are to bestiffened by a horizontal section of substantial strength nor-mally not more than 0.25 m from the upper edge of the coam-ing. Coaming brackets spaced not more than 3 m apart, are tobe fitted. The brackets are not to end on unstiffened plating.The coamings are to be satisfactorily stiffened against buck-ling.

Guidance note:In Position 2, the horizontal stiffening of the upper end of thecoaming can normally be omitted for hatches with area less than1.0 m2.


305 Stiffeners, brackets and coamings are to be able to with-stand the local forces set up by the clamping devices and/or thehandling facilities necessary for securing and moving the hatchcovers as well as vertical and horizontal mass forces from car-go stowed on the hatch covers, e.g. containers, see E200.

306 The strength of the stiffeners shall also comply with therequirements given in Ch.1 Sec.7 C. Maximum stiffener spac-ing is not to exceed 750 mm.

E. Hatch Covers

E 100 General101 The requirements below are valid for steel hatch coversin holds intended for dry cargo, liquid cargo and ballast.

102 Steel hatch covers are to be fitted to hatch openings onweather decks so as to ensure tightness consistent with opera-tional conditions and type of cover and to give effective pro-tection to the cargo in all sea conditions.

103 Requirements for small cargo tank hatch covers used foraccess and ventilation only, are given in I.

104 Materials for steel hatch covers are to satisfy the require-ments given for hull material.

Other material than steel may be used, provided the strengthand stiffness of covers are equivalent to the strength and stiff-ness of steel covers.

For aluminium alloys, see Ch.1 Sec.2 C.

I7 p b l

4

n2E

-----------------105 (cm

4)=

DET NORSKE VERITAS


105 Tank hatch covers of closed box type construction are tobe provided with effective means for ventilation and gasfree-ing.

106 Hatch covers are to be mechanically lockable in openposition.

107 Upon completion of installation of hatch covers, a chalktest is to be carried out. For tightness testing, see A400.

Guidance note:It is recommended that ships with steel hatch covers are suppliedwith an operation and maintenance manual including:

- opening and closing instructions

- maintenance requirements for packing, securing devices andoperating items

- cleaning instructions for the drainage system- corrosion prevention instructions- list of spare parts.


E 200 Design loads

201 All generally applicable lateral loads on hatch covers aregiven in Table E1, based upon the general loads given in Ch.1Sec.4.

a = 1.0 for weather decks forward of 0.15 L from FP, orforward of deckhouse front, whichever is the fore-most position

= 0.8 for weather decks elsewherepdp, ks = as given in Ch.1 Sec.4 C201h0 = vertical distance in m from the waterline at draught

T to the cover topav = vertical acceleration as given in Ch.1 Sec.4 B600q = deck cargo load in t/m2, as specified. Weather decks

above cargo holds in dry cargo ships are normally tobe designed for a minimum cargo load:

qmin = 1.0 for ships with L = 100 m = 1.3 for ships with L > 150 m when superstructure

deck = 1.75 for ships with L > 150 m when freeboard deck.

For ships with length between 100 and 150 m the q-value may be varied linearly.When it is specially stated that no deck cargo is tobe carried, the qmin may be discarded

ρc = dry cargo density in t/m3, if not otherwise specifiedto be taken as 0.7, see also Ch.1 Sec.4 C401

ρ = density of ballast, bunker or liquid cargo in t/m3,normally not to be less than 1.025 (i.e. ρ g0 ≈ 10)

HC = stowage height in m of dry cargo. Normally the'tweendeck height or height to top of cargo hatch-way to be used.

hs = vertical distance in m from the load point to top oftank, excluding smaller hatchways

hp = vertical distance in m from the load point to the topof air pipe

hb = vertical distance in metres from the load point to thedeepest equilibrium waterline in damaged conditionobtained from applicable damage stability calcula-tions. The deepest equilibrium waterline in dam-aged condition should be indicated on the drawingof the deck in question

∆ pdyn = as given in Ch.1 Sec.4 C300p0 = 25 in general = 15 in ballast holds in dry cargo vessels = pv when exceeding the general valuepv = pressure valve opening pressureH = height in m of tank

Table E1 Design loadsHatch cover at Load type p (kN/m2)

Weather decks 1)Sea pressure

Deck cargo

p2 = (g0 + 0.5 av) q

Cargo 'tweendecks p3 = ρc (g0 + 0.5 av) HC

Deck as tank top in general

Ballast or liquid cargo

p4 = ρ g0 hp + ∆ pdynp5 = ρ g0 hs + p0

Deck as tank top in tanks with breadth > 0.4 B

Deck as tank top towards ends of tanks with length > 0.15 L

Deck as tank top in tanks with unrestricted filling and with free breadth bt < 0.56B 4)

Watertight decks submerged in damaged condition 6) Sea pressure p9 = 10 hb

1) On weather decks combination of the design pressures p1 and p2 may be required for deck cargo with design stowage height less than 2.3 m.

2) For ships with service restrictions p1 may be reduced with the percentages given in Ch.1 Sec.4 B202. CW should not be reduced.

3) Distribution across hatch: Maximum value at one side linearly reduced to pv at other side.

4) For tanks with free breadth above 0.56 B the design pressure will be specially considered, see Ch.1 Sec.4 C305.

5) Distribution across hatch: Maximum value constant for 0.25 bt from one side, reduced to pv elsewhere.

6) The strength may be calculated with allowable stresses for plating, stiffeners and girders increased by 60 f1.

p1 a pdp 4 0.2ks+( )h0–( )2 ) minimum 5,0=

p6 ρg0 0.67 hs φb+( ) 0.12 H φ bt–[ ] pV3 )

+=

p7 ρg0 0.67 hs θl+( ) 0.12 Hθ lt–[ ] pV+=

p8 ρ 3B

100---------–

bt pV

5 )+=

DET NORSKE VERITAS


b = the largest athwartship distance in m from the loadpoint to the tank corner at the top of tank/ hold mostdistant from the load point

bt = breadth in m of top of tank/holdl = the largest longitudinal distance in m from the load

point to the tank corner at top of tank most distantfrom the load point

lt = length in m of top of tankφ = roll angle in radians as given in Ch.1 Sec.4 B400θ = pitch angle in radians as given in Ch.1 Sec.4 B500.

202 Horizontal loads from cargo stored on hatch covers aregiven by:

— Total transverse force:

PT = C at q lh bh (kN)

— Total longitudinal force:

PL = C al q lh bh (kN)

at = transverse acceleration as given in Ch.1 Sec.4 B700

al = longitudinal acceleration as given in Ch.1 Sec.4B 800

q = deck cargo load in t/m2, see Table E1lh = length of hatch in mbh = breadth of hatch in mq lh bh = total cargo mass (M) on hatch cover in tC = 0.5 when horizontal forces are combined with

vertical forcesC = 0.67 when horizontal forces are considered

alone.

If the cargo is secured (lashed etc.) to the deck outside thehatch cover, the horizontal load on covers may be reduced.

203 In addition to the distributed design loads specified in201, forces acting on hatch covers from heavy cargo units areto be taken into account as given in Ch.1 Sec.4 C500.

Deflections and loads due to movements and thermal effectsare also to be considered, see F 203.

204 Hatch covers subjected to wheel loading are to satisfythe strength requirements given in Pt.5 Ch.2 Sec.4 C.

E 300 Plating

301 The thickness corresponding to lateral pressure is givenby:

p = p1– p9, whichever is relevant, as given in Table E1σ = 0.58 σf N/mm2 for hatchways in position 1 or 2 when

p = p1 or p2 = 0.67 σf N/mm2 in all other casesσf = minimum upper yield stress in N/mm2. NV-NS-steel

may be taken as having σf = 235 N/mm2.

σf is not to be taken greater than 70% of the ultimatetensile strength.

302 The thickness of top plating is not to be less than:

t = 10 s (mm) , min. 6 mm.

303 The thickness of bottom plating of closed box construc-tion is not to be less than 6 mm.

304 Top or bottom plating acting as compression flanges inhatch cover main stiffening members (girders) is to be effec-tively stiffened against buckling.

In the middle half part of simply supported span the criticalbuckling stress is normally not to be less than:

— for hatchways in position 1 or 2:

— for hatchways in position 3:

η = stability factor (usage factor) = 0.77 for sea loads and wave induced internal liquid

loads = 0.87 for other loadsZR = Z according to 401 or 0.7 Z according to 402 (position

1 or 2), whichever gives the highest stress valueZA = actual section modulus in plate flange.

The critical buckling stress may be taken as:

or

σel =

k = 4 for plating with local stiffeners parallel to main stiff-ening members

=

for plating with local stiffeners perpendicular to mainstiffening members

c = 1.21 when local stiffeners are angles or T-sections = 1.10 when local stiffeners are bulb flats = 1.05 when local stiffeners are flat bars.

E 400 Stiffeners

401 The section modulus is given by:

p = p1– p9, whichever is relevant, as given in Table E1m = 8 for stiffeners simply supported at both ends, or sim-

ply supported at one end and fixed at the other end = 12 for stiffeners fixed at both endsσ = 0.58 σf N/mm2 for hatchways in position 1 or 2 when

p = p1 or p2 = 0.67 σf N/mm2 in all other cases.

Stiffeners subject to point loads from heavy cargo units (see203) are to be specially considered.

402 The section modulus for stiffeners of normal strengthsteel in position 1 or 2 is in no case to be less than:

m = as defined in 401

ql =

=

For other materials the requirement will be specially consid-ered. The allowable nominal tensile stress is normally given by

t15 8ka s p,

σ------------------------------ tk (mm)+=

σc

0.58σf

η-----------------

ZR

ZA------- N/mm

2( )=

σc

0 67σf,η

-----------------ZR

ZA------- N/mm

2( )=

σc σel when σel

σf

2-----≤=

σc σf 1σf

4σel-----------–

when σel

σf

2----->=

185000 kt tk–

1000s--------------

2N/mm

2( )

c 1sl--

2+

2

Z1000 l

2s p wk

mσ---------------------------------- (cm

3)=

Z103m

--------- l2

s ql wk (cm3)=

0.760 75,

76------------ L+

, maximum 1,75 t/m

2 in position 1

0.580 55,

76------------ L+

, maximum 1,30 t/m

2 in position 2

DET NORSKE VERITAS


σb /4.25, where σb is the ultimate tensile strength of the mate-rial.

403 The moment of inertia of steel members in position 1 or2, supported at side or end coamings only, is not to be less than:

I = 22 l 3 s ql (cm4)

ql = as defined in 402.

For other materials the requirement will be specially consid-ered. The requirement corresponds to a maximum allowabledeflection of 0.0028 l.

404 The requirements for section modulus and moment ofinertia given above are valid for strength members with a con-stant cross section over the entire span. Covers with graduallyreduced Z and I towards the ends of the span are to be designedso that the maximum bending stresses and deflections are notincreased.

With a Z-reduction towards ends, the rule section modulus atmiddle of span is to be multiplied by a factor:

α =

β =

l 1, l 0, Z1, and Z0 are given in Fig.1.

C1 is not to be taken less than 1.0.

With an I-reduction towards ends, the rule moment of inertia isto be multiplied by a factor:

δ =

I1 and I0 are given in Fig.1.

405 The net web area is not to be less than:

Fig. 1Hatch cover with variable cross-section

x = distance in m from the end of span to section consid-ered, and is not to be taken greater than 0.25 l

h = web height in m.

(IACS LL20)

406 The cover edges are to be adequately stiffened to with-stand the forces imposed upon them during opening and clos-ing of the hatches. For stiffness of cover edges, see also 600.

407 Stiffeners are to be connected to supporting girders or

cover edges by an area not less than:

a = 5 + 0.07 (l 1 + l 2) s p + ak (cm2)

l 1 and l 2 are stiffener spans in m on each side of support.

ak = corrosion addition in tanks corresponding to tk.

408 Weld attachment other than given in 407, are to be in ac-cordance with Ch.1 Sec.11.

For covers above cargo- and ballast tanks, chain or staggeredfillet welds on the tank side are not acceptable.

409 The web and flange thickness is not to be less than:

t = 5.0 + tk (mm)

tk as defined in Ch.1 Sec.2 Table D1, but assuming that thehatch cover is a part of the hold, or tank, as appropriate.

E 500 Girders501 When calculating the actual Z for strength members sup-porting other stiffeners, the effective flange is to be determinedin accordance with Ch.1 Sec.3 C400. When the hatch cover isof closed box girder construction, the flange may be taken as100 % effective.

502 The section modulus and moment of inertia are not to beless than according to the requirement given in 400, when s isreplaced by b.

b = half the sum in m of stiffener span on either side of thegirder.

503 The net web area at ends is not to be less than:

A = 0.07 l b p + 10 h tk (cm2)

b = as defined in 502h = as defined in 405.

At each intersection with supported members, A may be re-duced by the value 0.14 s b p towards the middle of the span, sbeing the distance in m between supported members. A is notto be taken less than 50% of the value at ends.

Web plates are to be effectively stiffened against buckling.

504 Double continuous fillet welds are normally to be usedwithin areas with shear stress greater than 75 N/mm2, and notless than 150 mm from each end of the girder. The throat thick-ness of the weld attachment between web plates and flanges inthese areas is normally not to be less than 0.4 t, where t = webplate thickness.

E 600 Stiffness of cover edges601 To ensure sufficient packing pressure for the whole dis-tance between the securing devices, the moment of inertia ofthe side elements of the covers is to be at least:

I = 6 pl a4 (cm4)

for cover edges connected to a rigid hatch coaming and

I = 12 pl a4 (cm4)

between cover edges of equal stiffness.

pl = packing line pressure along edges in N/mm, minimum5 N/mm

a = spacing in m of bolts or other securing devices.

602 When determining the moment of inertia of tank coverside elements supporting primary cover stiffening elements be-tween securing devices, the internal pressure in the tank is tobe taken into consideration.

E 700 Structural analysis701 For hatch covers of special construction or arrangement(e.g. covers constructed as a grillage, covers supported alongmore than two opposite edges, covers supporting other covers)

C1 13.2α β– 0 8,–

7β 0 4,+------------------------------------+=

l1

l0----

Z1

Z0------

C2 1 8α3 1 δ–

0 2, 3 δ+-------------------------+=

I1

I0----

A 0.14 0 5, xl---–

l s p 10 h tk (cm

2)+=

l0

Z0

l1

Z1

I1I0

DET NORSKE VERITAS


a separate strength calculation may be required, in which thearrangement of girders and supports is taken into account. Thisis specially valid for hatch covers in open bulk carriers andcombination carriers where deflections are important to tight-ness, see F203.

702 Load conditions are to be established in accordance withthe loads given in 200. For calculations according to beam the-ory the following stresses will be accepted:

a) Bending stress:

σ = 0.58 σf N/mm2 for hatchways in position 1 or 2when p = p1 or p2

= 0.67 σf N/mm2 in all other cases

b) Shear stress:

τ = 0.33 σf N/mm2 for hatchways in position 1 or 2when p = p1 or p2

= 0.37 σf N/mm2 in all other cases.

σf as defined in 301

The sum of girder bending stress and local bending stress in stiffeners being part of the girder is not to exceed 0.8 σf N/mm2

c) critical buckling stress:

η = 0.77 for sea loads and wave induced internal liquidloads (weather deck hatch covers)

= 0.87 for other loadsσa = actual calculated stress.

σc to be calculated as shown in 304.

703 For hatchway in position 1 or 2 additional conditionscorresponding to pressure 9.81 ql kN/m2ql are to be checked ( as defined in 402). For these conditions the following bend-ing stress for normal strength steel will be accepted:

σ = 95 N/mm2.

For other materials a bending stress of σb / 4.25 will normallybe accepted, σb being the ultimate tensile strength of the mate-rial.

Maximum deflection at the middle of hatch cover:

δ = 0.0028 ll = the smaller of hatch breadth and hatch length.

704 In way of holds/tanks for cargo oil and/or water ballast,the calculated scantlings for the hatch covers are to be in-creased by a corrosion addition tk as specified in Ch.1 Sec.1.

F. Hatchway Tightness Arrangement and Clos-ing Devices

F 100 General101 The requirements below are valid for steel hatch coverson weather decks and above tanks, with ordinary packing ar-rangement between hatch cover and coaming, and packing ar-ranged for vertical packing pressure in joints between coverelements. Other packing arrangements will be specially con-sidered.

102 Closing of hatches by portable hatch beams, covers andtarpaulins will be specially considered.

103 Packing and drainage arrangements of hatch covers forcargoes which are not sensitive to moisture from small leakag-

es may be specially considered.

F 200 Design and tightness requirements

201 The weight of covers and any cargo stowed thereon, to-gether with inertial forces generated by ship motions, are to betransmitted to the ship structure through steel to steel contact.This may be achieved by continuous steel to steel contact ofthe cover skirt plate with the ships structure or by means of de-fined bearing pads. A proper alignment between coaming andcover is very important in this respect.

202 The sealing is to be obtained by a continuous gasket ofrelatively soft, elastic material compressed to achieve the nec-essary weathertightness. Similar sealing is to be arranged be-tween cross-joint elements. Where fitted, compression flat barsor angles are to be well rounded where in contact with the gas-ket and are to be made of a corrosion-resistant material.

203 Special consideration is to be given to the gasket and se-curing arrangements in ships with large relative movementsbetween cover and ship structure or between cover elements.For such ships, relative deflections both in the vertical and thehorizontal planes should be calculated and submitted with thehatch cover plans. Also vertical deflections due to thermal ef-fects and internal pressure loads are to be considered.

For ships with large deck openings as defined in Ch.1 Sec.5,the torsional deformation of the hatch opening is to be calcu-lated based on a torsional moment

Mt = M ST + MWT

M ST , M WT = as given in Pt.5 Ch.2 Sec.6.

The necessary compression of the gasket to obtain sufficientsealing is to be estimated on the basis of the vertical deflectionscalculated, including building/installation tolerances, seen inrelation to results from compression/ leakage tests performed.

204 It is assumed that the gasket material and any gluing ma-terial used in gasket junctions or to fasten the gasket to the cov-er are of a quality suitable for all environmental conditionslikely to be experienced by the ship, and are compatible withthe cargoes carried. The material and form of gasket selectedis to be considered in conjunction with the type of cover, thesecuring arrangement and the expected relative movement be-tween cover and ship structure. The gasket is to be effectivelysecured to the cover.

205 There is to be a metallic contact between hatch cover andhull (earthing connection). If necessary, this is to be achievedby a special connection.

Guidance note:

1) As practical limits for the hatch opening horizontal defor-mations in ships with hatch openings less than given in Ch.1Sec.5 A106 (calculated with rule design loads) are indicat-ed:

- single amplitude diagonal deformation: ld/1000- bending deflection of coamings: lc/1000

l d = length of hatch opening diagonall c = length of side or end coaming.

2) Deflections due to temperature differences should bechecked, especially for closed (double-skin) hatch coverpontoons. The deflections should be calculated both for hotcargo (80°C) and cold air (–5°C) resulting in upward bend-ing of pontoon corners, and for hot air (60°C) and cold cargo(0°C) resulting in upward bending of middle of pontoon andpontoon edges. Securing devices are to be given sufficientstrength and pre-tension to reduce deflections to acceptablefigures.Designing the pontoons as open panels (one continuousplate flange only) will normally reduce the temperature de-flections effectively.

σc

σa

η----- (N/mm

2)≥

DET NORSKE VERITAS


Combination of loads and deflections should be based on aconsideration of the probability of simultaneous occurrence.

3) Laboratory compression tests should be performed on testpanels arranged for observing leakage for various combina-tions of internal liquid pressure and compression of gasket.By this a minimum compression/internal pressure curve forno leakage may be obtained. Necessary compression of gas-kets may thus be estimated by adding minimum compres-sion to maximum vertical deflections calculated.


F 300 Securing devices in general301 Panel hatch covers on weather decks above dry cargoholds or on top of deep tanks are in general to be secured byappropriate devices (bolts, wedges or similar) suitably spacedalongside the coamings and between cover elements. Arrange-ment and spacing are to be determined with due attention to theeffectiveness for tightness, depending upon the type and thesize of the hatch cover, as well as the stiffness of the cover edg-es between the securing devices, see E600. Scantlings of secur-ing devices are given in 400 to 600.

302 Securing means of other material than mild steel or othermeans than bolts are to be of strength equivalent to the require-ments given in 400 and 600, and so arranged that the correctpressure on the packing between the covers and the coamings,and adjacent covers as well, is obtained.

Bolts with nuts, wedges and other parts for securing the covers,are to be of reliable construction and securely attached to thehatchway coamings, decks or covers.

The individual securing elements are to have approximatelythe same deflection characteristics.

Bolts and adjusting screws are to be secured in position by ap-propriate means.

Where rod cleats are fitted, resilient washers or cushions are tobe incorporated.

Where hydraulic cleating is applied, the system is to remainmechanically locked in closed position in the event of failureof the hydraulic system.

303 Spare securing elements are to be kept on board, thenumber depending on the total number fitted, as well as type ofelement, special material used, etc.

F 400 Securing arrangement for weathertight hatch covers401 Ordinary packed hatch covers are to be secured to thecoaming by a net bolt area for each bolt not less than:

a = spacing of bolts in m

f1e =

σf = minimum upper yield stress in N/mm2, not to be takengreater than 70% of the ultimate tensile strength

e = 0.75 for σf > 235 = 1.0 for σf < 235.

402 Between cover and coaming and at cross-joints, a pack-ing line pressure sufficient to obtain weathertightness is to bemaintained by a bolt area as given in 401.

403 For packing line pressures exceeding 5 N/mm, the areais to be increased accordingly. The packing line pressure is tobe specified.

404 The net bolt diameter is not to be less than 19 mm forhatchways exceeding 5 m2 in area.

405 Closing appliances of covers to hatches on exposeddecks (position 1 and 2) where reduced coaming heights areaccepted (see D 200) will be specially considered.

In this case each cover element is to be equipped with at least2 securing devices along each side, and the maximum distanceis not to exceed amax = 2.5 metres.

F 500 Securing arrangement for deep tank or cargo oil tank hatch covers501 In addition to the requirements given in 400, deep tankor cargo oil tank hatch covers have to fulfil the following re-quirements.

The net securing bolt area for each bolt is not to be less than:

a = spacing of bolts in ml = span in m of hatch cover girder or stiffener perpendic-

ular to coaming, if any — or distance from cover edgeto the first parallel stiffener

p = p4 – p9, whichever is relevant, as given in Table E1pl = packing line pressure in N/mm. For calculation pur-

pose, however, the packing pressure is not to be takenless than 5 N/mm

f1e = as given in 401.

502 Between cover elements the packing line pressure is tobe maintained by a net bolt area for each bolt not less than:

a = spacing of bolts in m.

Corrections to be applied as given in 403 and 404.

503 Covers particularly calculated, as mentioned in E700,are to be fitted with closing devices corresponding to the reac-tion forces found by the calculation. The maximum tension inway of threads of bolts is not to exceed 125 f1e N/mm2 .. Themaximum stresses in closing devices of other types than boltsare:

— normal stress:

σ = 120 f1e N/mm2

— shear stress:

τ = 80 f1e N/mm2

— equivalent stress:

Guidance note:In order to satisfy the tightness requirements the following de-sign recommendations are given:

1) The horizontal distance between the gaskets and the secur-ing devices should be as small as possible.

2) Securing devices should be arranged as close to the panelcorners as possible.

3) Securing devices with a vertical clearance (passive cleating)should be avoided, i.e. active cleating with a certain pre- ten-sion should be used.


F 600 Securing arrangement for hatch covers carrying deck cargo601 In addition to the requirements given in 400 or 500, all

A1.4af1e

----------- (cm2

)=

σf

235---------

e

A0.08a

f1e-------------- 0.5lp pl+( ) (cm

2 )=

A3af1e------- (cm

2 )=

σe σ23τ2

+ 150 f1e N/mm2

= =

DET NORSKE VERITAS


hatch covers, especially those carrying deck cargo are to be ef-fectively secured against horizontal shifting due to the hori-zontal forces given in E202, which may be reduced by 10%due to friction.

The maximum allowable stresses in stoppers are as given in503.

602 To prevent damage to hatch covers and ship structure,the location of stoppers is to be compatible with the relativemovements between hatch covers and ship structure. Thenumber of stoppers is to be as small as possible, preferablyonly one stopper at each end of each cover element.

In case of twin hatches supported by a narrow box girder atcentre-line, two-way stopper at outboard coaming may be re-quired.

603 Towards the ends of the ship vertical acceleration forcesmay exceed the gravity force. The resulting lifting forces mustbe considered when dimensioning the securing devices. Alsolifting forces from cargo secured on the hatch cover duringrolling are to be taken into account. The allowable stresses inbolts and other types of securing devices are as given in 503.

604 Hatch coamings and supporting structure are to be ade-quately stiffened to accommodate the loading from hatch cov-ers.

605 At cross-joints of multi-panel covers vertical guides(male/female) are to be fitted to prevent excessive relative ver-tical deflections between loaded/unloaded panels.

F 700 Drainage arrangement701 On weather deck hatch covers drainage is to be arrangedinside the line of gasket by means of a gutter bar or vertical ex-tension of the hatch side and end coaming.

702 Drain openings are to be arranged at the ends of drainchannels and are to be provided with effective means for pre-venting ingress of water from outside, such as non-returnvalves or equivalent.

703 Cross-joints of multi-panel covers are to be arrangedwith drainage of water from the space above the gasket and adrainage channel below the gasket.

704 If a continuous outer steel contact between cover andship structure is arranged, drainage from the space between thesteel contact and the gasket is also to be provided for.

G. Internal Doors and Hatches for Watertight Integrity

G 100 General101 General requirements for internal openings in connec-tion with watertight integrity are given in Ch.1 Sec.3 A600.For pipe tunnel openings, see also Ch.1 Sec.6 A407.

102 Watertight doors or hatches may be of the followingtypes:

— hinged doors or hatches, dividing cargo spaces, shall be ofan approved type with mechanical securing devices andmay be fitted 'tween decks in approved positions. Suchdoors shall not be used where remote control is required.Hinged doors for passage shall have central locking, andtighteners shall be mounted on the hinged side

— rolling doors, guided and supported by steel rollers, andwith mechanical or hydraulic securing devices

— sliding doors, moving along and supported by track-waygrooves and with mechanical locking due to taper and fric-tion. A positive force shall be required to re-open thedoors. These types of door may be only hand operated orboth power and hand operated. Sliding doors shall have anindication (i.e., a red light) placed locally on both sides

showing that the door is in the remote control mode.(IACS UI SC156). Signboards and instructions shall beplaced in way of the door advising how to act when thedoor is in the “door closed” mode. In passenger areas andareas of high ambient noise , audible alarms shall be sup-plemented by visual signals on both sides of the door.

G 200 Operation201 All watertight doors and access hatches are to be opera-ble from both sides of the bulkhead or deck.

202 Remotely controlled doors are also to be locally opera-ble. Indicators are to be provided at the control position to in-dicate whether the doors are open or closed.

G 300 Strength301 Watertight doors and hatches are to be designed with astrength equivalent to that of the structure in which they are po-sitioned. They are to withstand the design pressure from bothsides.

302 The thickness corresponding to lateral pressure is givenby:

p = design pressure p, as given in Ch.1 Sec.9, Table B1c = 1.58 for collision bulkhead = 1.35 for all other bulkheads and decks.

The thickness is in no case to be less than the minimum bulk-head thickness.

303 The stiffener section modulus requirement is given by:

p = as given in 302c1 = 0.8 for collision bulkhead = 0.6 for all other bulkheads and decks.

304 Edge stiffeners of doors are to have a moment of inertianot less than:

I = 8 pe d4 (cm4)

d = distance between closing devices in m, to be measuredalong door edge

pe = packing line pressure along edges, not to be taken lessthan 5 N/mm

= pb, whichever is the greaterp = design pressure p1 as given in Ch.1 Sec.9, Table B1b = load breadth, normally taken as h/3 or w/2, whichever

is the less.

h and w are height and width of door in m.

305 The coaming of watertight doors (door frame) is to bedesigned with due care to necessary stiffness in order to avoidlarge deflections resulting in leakage in the damaged condi-tion. The door frames shall have no groove at the bottom inwhich dirt might lodge and prevent the door from closing prop-erly.

306 Securing devices are to be designed for the load actingalso on the opposite side of where they are positioned. Allow-able stresses in securing devices are as follows:

normal stress: σ = 165 f1 N/mm2

shear stress: τ = 110 f1 N/mm2

equivalent stress:

tckas p

f1

------------------ tk (mm)+=

Zc1 l

2s p wk

f1--------------------------- (cm

3 )=

σe σ23τ2

+ 200f1e N/mm2

= =

DET NORSKE VERITAS


H. Ventilators

H 100 Coamings and closing arrangements

101

1) Ventilators in position 1 or 2 to spaces below freeboarddeck or decks of enclosed superstructures shall havecoamings of steel or other equivalent material, substantial-ly constructed and efficiently connected to the deck.Where the coamings of any ventilators exceed 900 milli-metres in height it shall be specially supported.

2) Ventilators passing through superstructures other than en-closed superstructures shall have substantially constructedcoamings of steel or other equivalent material at the free-board deck.

3) Ventilators in position 1 the coamings of which extend tomore than 4.5 metres above the deck, and in position 2 thecoamings of which extend to more than 2.3 metres abovethe deck, need not be fitted with closing arrangements un-less specifically required by the Society.

4) Except as provided in (3) ventilator openings shall be pro-vided with efficient weathertight closing appliances. Inships of not more than 100 metres in length the closing ap-pliances shall be permanently attached; where not so pro-vided in other ships, they shall be conveniently stowednear the ventilators to which they are to be fitted. Ventila-tors in position 1 shall have coamings of a height of at least900 millimetres above the deck; in position 2 the coamingsshall be of a height of at least 760 millimetres above thedeck.

5) In exposed positions, the height of coamings may be re-quired to be increased to the satisfaction of the Society.

(ICLL Reg.19)

102 Reduced coaming height may be accepted for vesselstrading in domestic waters only, in accordance with Pt.1 Ch.1Sec.2 B 900.

H 200 Thickness of coamings

201 The thickness of ventilator coamings is not to be lessthan given in the following table:

For intermediate external diameter the wall thickness is ob-tained by linear interpolation.

(IACS LL36)

H 300 Arrangement and support

301 Where required by 101, weathertight closing appliancesfor all ventilators in positions 1 and 2 are to be of steel or otherequivalent materials.

Wood plugs and canvas covers are not acceptable in these po-sitions.

(IACS LL52)

302 The deck plating in way of deck openings for ventilatorcoamings is to be of sufficient thickness, and efficiently stiff-ened between ordinary beams or longitudinals. Coamings withheights exceeding 900 mm are to be additionally supported.

303 Where ventilators are proposed to be led overboard in anenclosed superstructure deck house or shipside the closing ar-rangement is to be submitted for approval. If such ventilatorsare lead overboard more than 4.5 m above the freeboard deck,closing appliances may be omitted, provided that satisfactory

baffles and drainage arrangements are provided.

304 To ensure satisfactory operation in all weather condi-tions, machinery spaces and emergency generator room venti-lation inlets and outlets are to be located in such positions thatclosing appliances will not be necessary.

Alternatively, depending on vessel's size and arrangement,lesser coaming heights may be accepted if weathertight closingappliances are provided, in accordance with 101 and in combi-nation with suitable means arranged to ensure uninterruptedand adequate supply of air to these spaces.

Guidance note:The term suitable means is meant e.g. that direct and sufficientsupply of air is provided through open skylights, hatches or doorsat a higher level than the heights required by 101.


I. Tank Access, Ullage and Ventilation Openings

I 100 General

101 The number of hatchways and other openings in thetank deck are not to be larger than necessary for reasonable ac-cess to and ventilation of each compartment.

102 Hatchways, openings for ventilation, ullage plugs orsighting ports, etc. are not to be placed in enclosed compart-ments where there is a danger of accumulation of gases.

Ullage plugs or sighting ports should be fitted as high abovethe deck as practicable, for instance in the cover of accesshatches.

Access hatches to holds or other openings, for example fortank cleaning devices, are to be of substantial construction, andmay be arranged in the main hatch covers.

I 200 Hatchways

201 The thickness of the hatch coaming is not to be less thangiven in Ch.1 Sec.10 for a deckhouse in the same position.

202 The thickness of covers is not to be less than:

— 12.5 mm for cover area exceeding 0.5 m2

— 10.0 mm for cover area less than 0.25 m2.

For intermediate areas the thickness may be linearly varied.

203 Where the area of the hatchway exceeds 1.25 m2, thecovers are to be stiffened.

204 Covers are to be secured to the hatch coamings by fas-tenings spaced not more than 380 mm apart and not more than250 mm from the corners. For circular covers the fasteningsare not to be spaced more than 450 mm apart.

205 Other types of covers may be approved, provided theirconstruction is considered satisfactory.

I 300 Air Pipes

301 Where air pipes to ballast and other tanks extend abovethe freeboard or superstructure decks, the exposed parts of thepipes shall be of substantial construction; the height from thedeck to the point where water may have access below shall beat least 760 millimetres on the freeboard deck and 450 milli-metres on the superstructure deck. Where these heights mayinterfere with the working of the ship, a lower height may beapproved, provided the Society is satisfied that the closing ar-rangements and other circumstances justify a lower height.Satisfactory means permanently attached, shall be provided forclosing the openings of the air pipes.

(ICLL Reg.20)

External diameter in mm

Wall thickness in mm

≤ 80 6.0≥165 8.5

DET NORSKE VERITAS


302 For ships assigned timber freeboards the air pipes shouldbe provided with automatic closing appliances.

(IACS LL10)

303 Where required by 301 air pipe closing devices shall beweathertight. Closing devices shall be automatic if, while thevessel is at its draught corresponding to summer load line, theopenings of air pipes to which these closures are fitted sub-merge at angles up to 40° or up to a lesser angle which may beagreed on the basis of stability requirements. Pressure- vacuumvalves (PV valves) may, however, be accepted on tankers.

Wooden plugs and trailing canvas hoses shall not be acceptedin position 1 and position 2.

Guidance note:The member Societies in formulating this interpretation realisethat pressure-vacuum valves (PV valves) presently installed ontankers do not theoretically provide complete watertightness. Inview, however, of experience of this type of valve and the posi-tion in which they are normally fitted it was considered theycould be accepted.


(IACS LL49)

304 The thickness of air pipe coamings is not to be less thangiven in the following table:

For intermediate external diameter the wall thickness is ob-tained by linear interpolation. Coamings with heights exceed-ing 900 mm are to be additionally supported. (IACS LL36)

305 Openings of air pipes are to be provided with perma-nently attached efficient means of closing. The closing appli-ances are to be so constructed that damage to the tanks byoverpumping or occasionally possible vacuum by dischargingis prevented.

306 In cases where air pipes are led through the side of su-perstructures, the height of their openings to be at least 2.3 me-tres above the summer water line. Automatic vent heads ofapproved design are to be provided.

307 The height of air pipes may be required to be increasedon ships of type "A", type "B-100" and type "B-60" where thisis shown to be necessary by the floatability calculation.

308 In a ship to which timber freeboard is assigned, air pipeswhich will be inaccessible when the deck cargo is carried areto be provided with automatic closing appliances.

309 All air pipes in cargo spaces are to be well protected.

310 For arrangement and size of air pipes, see also Pt.4 Ch.6Sec.4 K.

J. Machinery Space Openings

J 100 Openings

101 Machinery space openings in position 1 or 2 shall beproperly framed and efficiently enclosed by steel casings ofample strength, and where the casings are not protected by oth-er structures their strength shall be specially considered. Ac-cess openings in such casings shall be fitted with doorscomplying with the requirements of B101, the sills of which

shall be at least 600 millimetres above the deck if in position 1,and at least 380 millimetres above the deck if in position 2.Other openings in such casings shall be fitted with equivalentcovers, permanently attached in their proper positions.

102 Coamings of any machinery space ventilator in an ex-posed position shall be in accordance with H304

(ICLL Reg. 17)

103 Where casings are not protected by other structures,double doors should be required for ships assigned freeboardsless than those based on Table B in the ICLL. An inner sill of230 mm in conjunction with the outer sill of 600 mm is recom-mended.

(IACS LL7)

104 Doorways in engine and boiler casings are to be ar-ranged in positions which afford the greatest possible protec-tion.

105 Skylights are to be of substantial construction and se-curely connected to deck. If the upper part of the skylight con-sists of hinged scuttles, effective means for closing andsecuring are to be provided.

For skylights in position 1 or 2 the coaming height is not to beless than given for hatchway coamings. For skylights in posi-tion 1, deadlights are to be fitted.

106 Side scuttles in engine casings are to be provided withfireproof glass.

K. Scuppers, Inlets and Discharges

K 100 Inlets and discharges

101

Discharges led through the shell either from spaces below thefreeboard deck or from within superstructures and deckhouseson the freeboard deck fitted with doors complying with the re-quirements of B101 shall be fitted with efficient and accessiblemeans for preventing water from passing inboard. Normallyeach separate discharge shall have one automatic non-returnvalve with a positive means of closing it from a position abovethe freeboard deck. Where, however, the vertical distance fromthe summer load waterline to the inboard end of the dischargepipe exceeds 0.01 L, the discharge may have two automaticnon-return valves without positive means of closing, providedthat the inboard valve is always accessible for examination un-der service conditions; where that vertical distance exceeds0.02 L a single automatic non return valve without positivemeans of closing may be accepted subject to the approval ofthe Society. The means for operating the positive action valveshall be readily accessible and provided with an indicatorshowing whether the valve is open or closed.

All shell fittings, and the valves required by this Rule shall beof steel, bronze or other approved ductile material. Valves ofordinary cast iron or similar material are not acceptable. Allpipes to which this Rule refers shall be of steel or other equiv-alent material to the satisfaction of the Society, see Pt.4 Ch.6Sec.2.

(ICLL Reg.22)

102 It is considered that the position of the inboard end ofdischarges should be related to the timber summer load water-line when timber freeboard is assigned.

(IACS LL22)

External diameter in mm

Wall thickness in mm

≤ 80 6.0≥ 165 8.5

DET NORSKE VERITAS


103 It is considered that an acceptable equivalent to one au-tomatic non-return valve with a positive means of closing froma position above the freeboard deck would be one automaticnon-return valve and one sluice valve controlled from abovethe freeboard deck. Where two automatic non-return valves arerequired, the inboard valve must always be accessible underservice conditions, i.e., the inboard valve should be above thelevel of the tropical load water line. If this is not practicable,then, provided a locally controlled sluice valve is interposedbetween the two automatic non-return valves, the inboardvalve need not to be fitted above the SWL.

Where sanitary discharges and scuppers lead overboardthrough the shell in way of machinery spaces, the fitting toshell of a locally operated positive closing valve, together witha non-return valve inboard, is considered to provide protection

equivalent to the requirements of 101.

It is considered that the requirements of 101 for non-returnvalves are applicable only to those discharges which remainopen during the normal operation of a vessel. For dischargeswhich must necessarily be closed at sea, such as gravity drainsfrom topside ballast tanks, a single screw down valve operatedfrom the deck is considered to provide efficient protection.

The inboard end of a gravity discharge which leads overboardfrom an enclosed superstructure or space is to be located abovethe water line formed by a 5 degree heel, to port or starboard,at a draft corresponding to the assigned summer freeboard.

It is considered that the position of the inboard end of discharg-es shoul be related to the timber summer load waterline whentimber freeboard is assigned.

Table K1 Acceptable arrangements of discharges with inboard endsDischarges coming from defined enclosed spaces (spaces below freeboard deck, in superstructures

and in deck houses defined by Reg.3 (10) with doors according to Reg.12 and defined by Reg.18 (2))

Discharges coming from open deck and from spaces not defined

General requirements (Reg.22 (1))

In engine rooms only

Alternatives where inboard end is:

(Reg.22 (1))

Outboard end > 450 mm below

FB DECK or < 600 mm above SWL (Reg.22 (3))

Otherwise Reg.22(4)

> 0.01 x L above SWL

> 0.02 x L above SWL

*) The control shall be so sited as to allow adequate time for operation in case of influx of water to the space having regard to the time which could be taken to reach and operate such controls

**) Substantial pipe thickness from the shell and up to the freeboard deck and in cases further up in closed superstructure to a height at least 600 mm above the summer water line

***) References: ICLL regulations

DET NORSKE VERITAS


See Table K1 for the acceptable arrangement of scuppers, in-lets, and discharges.

104 Discharges with inboard opening located lower than theship's uppermost load line may be accepted when a loop of thepipe is arranged, extending not less than 0.01 L (minimum 0.5m) above the summer load waterline. The top of the loop is tobe regarded as the position of the inboard opening, and thepipeline is to be provided with valves according to 101.

105 Discharges from spaces above the freeboard deck are tobe of steel or material specially resistant to corrosion.

106 Adequate protection is to be provided to protect valvesor pipes from being damaged by cargo, etc.

107 Plastic pipes may be used for sanitary discharges andscuppers as permitted by Pt.4 Ch.6 Sec.2 A700.

108 The portion of discharge line from the shell to the firstvalve as well as shell fittings and valves shall be of steel,bronze or other approved ductile material.

109 In manned machinery spaces main and auxiliary sea in-lets and discharges in connection with the operation of machin-ery may be controlled locally. The controls shall be readilyaccessible and shall be provided with indicators showingwhether the valves are open or closed.

110 Scuppers and discharge pipes originating at any leveland penetrating the shell either more than 450 millimetres be-low the freeboard deck or less than 600 millimetres above thesummer load waterline shall be provided with a non-returnvalve at the shell. This valve, unless required by 101, may beomitted if the piping is of substantial thickness.

K 200 Pipe thickness

201 The wall thickness of steel piping between hull platingand closeable or non-return valve is not to be less than given inTable K2.


202 The wall thickness of steel piping inboard of the valve isnot to be less than given in Table K3.


(IACS LL36)

K 300 Scuppers

301 A sufficient number of scuppers, arranged to provide ef-fective drainage, is to be fitted on all decks.

302 Scuppers on weather portions of decks and scuppersleading from superstructures or deckhouses not fitted withdoors complying with B101 shall be led overboard.

303 Scuppers led through the shell from enclosed superstruc-tures used for the carriage of cargo shall be permitted onlywhere the edge of the freeboard deck is not immersed when theship heels 5 degrees either way. In other cases the drainageshall be led inboard in accordance with the requirements of theInternational Convention for the Safety of Life at Sea in force.

304 Scuppers led through the deck or shell, are to complywith requirements to material and thickness as given for dis-charges.

305 Scupper pipes are to be well stayed to prevent any vibra-tions. However, sufficient possibility for expansion of thepipes to be provided when necessary.

306 Scuppers from spaces below the freeboard deck or spac-es within closed superstructures, may be led to bilges. Fordrainage of cargo deck spaces, see Pt.4 Ch.6 Sec.4 D.

307 Scuppers leading overboard from spaces mentioned in306, are to comply with the requirements given for discharges.Scuppers from exposed superstructure deck, led through theship's sides and not having closeable valves, are to have wallthickness as required in 201 and 202.

308 Gravity discharges from top wing tanks may be ar-ranged. The drop valves are to be of substantial constructionand of ductile material, and they are to be closeable from an al-ways accessible position. It is to be possible to blank- flangethe discharge or to lock the valves in closed position when thetanks are used for carrying cargo.

The thickness of the pipe or box leading from the tank throughthe shell is to comply with the requirements given for discharg-es.

309 Drainage from refrigerated cargo spaces is to complywith the requirements for class notation Reefer. Drain pipesfrom other compartments are not to be led to the bilges in re-frigerated chambers.

310 Drainage from helicopter decks is to comply with the re-quirements for the class notation HELDK S.

K 400 Periodically unmanned machinery space

401 The location of the controls of any valve serving a seainlet, a discharge below the waterline or a bilge injection sys-tem shall be so sited as to allow adequate time for operation incase of influx of water to the space, having regard to the timelikely to be required in order to reach and operate such con-trols. If the level to which the space could become flooded withthe ship in the fully loaded condition so requires, arrangementsshall be made to operate the controls from a position abovesuch level.

(SOLAS Reg. II-1/48.3)

402 If it can be documented by calculation of filling time thatthe water level is not above the tank top floor after 10 minutesfrom the initiation of the uppermost bilge level alarm, it will beaccepted that the valves are operated from the tanktop floor.

Guidance note:Various Flag Administrations have worked out their own inter-pretations of this regulation.


L. Side Scuttles, Windows and Skylights

L 100 Side Scuttles, Windows and Skylights

101

1) Side scuttles and windows together with their glasses,deadlights and storm covers, if fitted, shall be of an ap-proved design and substantial construction. Non-metallicframes are not acceptable.Guidance note:Deadlights are fitted to the inside of windows and side scuttleswhile 'storm covers' are fitted to the outside of windows, whereaccessible, and may be hinged or portable.


Table K2 Wall thickness of steel pipingExternal diameter in mm Wall thickness in mm

≤ 80 7.0= 180 10.0≥ 220 12.5

Table K3 Wall thickness of steel pipingExternal diameter in mm Wall thickness in mm

≤ 155 4.5≥ 230 6.0

DET NORSKE VERITAS


2) Side scuttles are defined as being round or oval openingswith an area not exceeding 0.16 m2. Round or oval open-ings having areas exceeding 0.16 m2 shall be treated aswindows.

3) Windows are defined as being rectangular openings gen-erally, having a radius at each corner relative to the win-dow size and round or oval, openings with an areaexceeding 0.16 m2 .

4) Side scuttles to the following spaces shall be fitted withhinged inside deadlights:

a) spaces below freeboard deck

b) spaces within the first tier of enclosed superstructures

c) first tier deckhouses on the freeboard deck protectingopenings leading below or consideredbuoyant in sta-bility calculations.

Deadlights shall be capable of being closed and securedwatertight if fitted below the freeboard deck and weather-tight if fitted above.

5) Side scuttles shall not be fitted in such a position that theirsills are below a line drawn parallel to the freeboard deckat side and having its lowest point 2.5 percent of thebreadth B, or 500 mm, whichever is the greatest distance,above the summer load line (or timber summer load line ifassigned) .

6) If required damage calculations indicate that side scuttleswould become immersed in any intermediate stage offlooding or the final equilibrium waterlines they shall beof the non-opening type.

7) Windows shall not be fitted in the following locations:

a) below the freeboard deck

b) in the first tier end bulkheads or sides of enclosed su-perstructures

c) in first tier deckhouses that are considered buoyant inthe stability calculations.

8) Side scuttles and windows at the side shell in the secondtier shall be provided with hinged inside deadlights capa-ble of being closed and secured weathertight if the super-structure protects direct access to an opening leadingbelow or is considered buoyant in the stability calcula-tions.

9) Side scuttles and windows in side bulkheads set inboardfrom the side shell in the second tier, which protecting di-rect access below to spaces listed in paragraph (4), shall beprovided with either hinged inside deadlights or, wherethey are accessible, permanently attached external stormcovers which are capable of being closed and securedweathertight.

10) Cabin bulkheads and doors in the second tier and aboveseparating side scuttles and windows from a direct accessleading below or the second tier considered buoyant in thestability calculations, may be accepted in place of dead-lights or storm covers fitted to the side scuttles and win-dows.

11) Deckhouses situated on a raised quarter deck or on thedeck of a superstructure of less than standard height, maybe regarded as being in the second tier as far as the require-ments for deadlights are concerned, provided the height ofthe raised quarter deck or superstructure is equal to orgreater than the standard quarter deck height.

12) Fixed or opening skylights shall have glass thickness ap-propriate to their size and position as required for sidescuttles and windows. Skylight glasses in any position

shall be protected from mechanical damage and where fit-ted in positions 1 or 2, shall be provided with permanentlyattached deadlights or storm covers.

Guidance note:Deviation for the fitting of deadlights may be accepted for ves-sels trading in domestic waters only, in accordance with Pt.1Ch.1 Sec.2 B 900.


(IACS LL62, ICLL Reg. 23)

L 200 Glass dimensions, side scuttles and windows

201 Side scuttles and windows made and tested according toISO 1751 for side scuttles and ISO 3903 for windows, withglass according to ISO 1095 for side scuttles and 3254 for win-dows and glass tested and marked according to ISO 614 willnormally be accepted. The same applies to national standardsequivalent to the ISO-standards.

202 The glass thickness can be calculated from the followingformulae:

1) The design load shall be in accordance with the rules asgiven in Ch.1 Sec.10 C100.For 2nd tier and below the design load for side scuttles andwindows is in addition to be in accordance with ISO/DIS5779 and 5780.

2) “The minimum design load for windows in sides and aftends of deckhouses located 1.7 Cw (m) or more aboveS.W.L., may be reduced to 2.5 kN/m2.L should not be taken less than 100 m.The thickness of windows are not to be less than:

— 8 mm for windows with area less than 1.0 m2

— 10 mm for windows of 1.0 m2 or more.

N = nominal diameter/light opening of side scuttle in mmb = the minor dimension of the window in mmβ = factor obtained from the graph in Fig. 2p = design load in kN/m2

t = glass thickness in mmCw = wave coefficient as given in Ch.1 Sec.4 B200.

Fig. 2Diagram for factor β for windows

side scuttles: tN

362--------- p=

windows: tb

200--------- β p=

DET NORSKE VERITAS


M. Freeing Ports

M 100 Definitions101 Where bulwarks on the weather portions of freeboard orsuperstructure decks form wells, ample provision shall bemade for rapidly freeing the decks of water and for drainingthem.

M 200 Freeing port area201 Except as provided in 202 and 203, the minimum free-ing port area (A) on each side of the ship for each well on thefreeboard deck shall be that given by the following formula incases where the sheer in way of the well is standard or greaterthan standard. The minimum area for each well on super-structure decks shall be one-half of the area given by the for-mula.

Where the length of bulwark ( l) in the well is 20 metres or less:

A = 0.7 + 0.035 l (square metres),

where l exceeds 20 metres:

A = 0.07 l (square metres).

l need in no case be taken as greater than 0.7 L.

If the bulwark is more than 1.2 metres in average height the re-quired area shall be increased by 0.004 square metres per metreof length of well for each 0.1 metre difference in height. If thebulwark is less than 0.9 metre in average height, the requiredarea may be decreased by 0.004 square metres per metre oflength of well for each 0.1 metre difference in height.

202 In ships with no sheer the area calculated according to201 shall be increased by 50 per cent. Where the sheer is lessthan the standard the percentage shall be obtained by linear in-terpolation.

203 Where a ship fitted with a trunk which does not complywith the requirements of ICLL Regulations 36 (1)(e) or wherecontinuous or substantially continuous hatchway side coamingare fitted between detached superstructures the minimum areaof the freeing port openings shall be calculated from the fol-lowing table:

The area of freeing ports at intermediate breadths shall be ob-tained by linear interpolation.

204 In ships having superstructures which are open at eitheror both ends, adequate provision for freeing the space withinsuch superstructures shall be provided to the satisfaction of theSociety.

For superstructures that are open at either or both ends the ef-fective freeing area at the end of the superstructure may beadded to the respective freeing port area for the port and star-board side of the superstructure. The effective area of the open-ing at the end of a superstructure will be assessed on a case bycase basis weighing the following factors:

— the athwartship location of the opening— the slope of the deck towards or away from the opening— the length/breadth ratio of the well— the free fore and aft passage for the water to reach the

opening, unobstructed by deck equipment, fittings, or car-go stowage.

Guidance note:Reduced freeing port area may be accepted for vessels trading indomestic waters only, in accordance with Pt.1 Ch.1 Sec.2 B 900.


M 300 Location and protection of openings

301 The lower edges of the freeing ports shall be as near thedeck as practicable. Two-thirds of the freeing port area re-quired shall be provided in the half of the well nearest the low-est point of the sheer curve.

302 All such openings in the bulwarks shall be protected byrails or bars spaced approximately 230 millimetres apart. Ifshutters are fitted to freeing ports, ample clearance shall beprovided to prevent jamming. Hinges shall have pins or bear-ings of non-corrodible material. If shutters are fitted with se-curing appliances, these appliances shall be of approvedconstruction.

(ICLL Reg.24)

M 400 Multiple wells

401 On a flush deck ship with a substantial deckhouse amid-ships it is considered that the deckhouse provides sufficientbreak to form two wells and that each could be given the re-quired freeing port area based upon the length of the «well». Itwould not then be allowed to base the area upon 0.7 L.

In defining a substantial deckhouse it is suggested that thebreadth of the deckhouse should be at least 80% of the beam ofthe vessel, and that the passageways along the side of the shipshould not exceed 1.5 m in width.

Where a screen bulkhead is fitted completely across the vessel,at the forward end of a midship deckhouse, this would effec-tively divide the exposed deck into wells and no limitation onthe breadth of the deckhouse is considered necessary in thiscase.

It is considered that wells on raised quarterdecks should betreated as previously, i.e. as being on freeboard decks.

With zero or little sheer on the exposed freeboard deck or anexposed superstructure deck it is considered that the freeingport area should be spread along the length of the well.

(IACS LL13)

M 500 Free flow area

501 The effectiveness of the freeing area in bulwarks re-quired by 201 and 202 depends on free flow across the deck ofa ship. Where there is no free flow due to the presence of a con-tinuous trunk or hatchway coaming, the freeing area in bul-warks is calculated in accordance with 203.

The free flow area on deck is the net area of gaps betweenhatchways, and between hatchways and superstructures anddeckhouses up to the actual height of the bulwark.

The freeing port area in bulwarks should be assessed in relationto the net flow area as follows:

(i) If the free flow area is not less than the freeing area calcu-lated from 203 as if the hatchway coamings were continuous,then the minimum freeing port area calculated from 201 and202 should be deemed sufficient.

(ii) If the free flow area is equal to, or less than the area calcu-lated from 201 and 202 minimum freeing area in the bulwarksshould be determined from 203.

(iii) If the free flow area is smaller than calculated from 203but greater than calculated from 201 and 202, the minimumfreeing area in the bulwark should be determined from the fol-lowing formula:

F = F1 + F2 – fp (m2)

F1 = the minimum freeing area calculated from 201 and202,

F2 = the minimum freeing area calculated from 203,fp = the total net area of passages and gaps between hatch

ends and superstructures or deckhouses up to the actualheight of bulwark.

Breadth of hatchway or trunk in relation to

the breadth of ship

Area of freeing ports in relation to the total area

of the bulwarks40% or less

75% or more20%10%

DET NORSKE VERITAS


(IACS LL44)

M 600 Type «A», «B-100» and «B-60» ships601 Requirements for freeing arrangements for Type «A»ships are given in N100.

602 Type B-100 ships with bulwarks shall have open railsfitted for at least half the length of the exposed parts of theweather deck or a freeing port area, in the lower part of the bul-warks, of 33% of the total area of the bulwarks. For Type B-60ships there shall be freeing port area in the lower part of thebulwarks equal to at least 25% of the total area of the bulwarks.

N. Special Requirements for Type A Ships

N 100 Machinery casings101 Machinery casings on Type A ships shall be protectedby an enclosed poop or bridge of at least standard height, or bya deckhouse of equal height and equivalent strength, providedthat machinery casings may be exposed if there are no open-ings giving direct access from the freeboard deck to the ma-chinery space. A door complying with the requirements ofB101 may, however, be permitted in the machinery casing,provided that it leads to a space or passageway which is asstrongly constructed as the casing and is separated from thestairway to the engine room by a second weather tight door ofsteel or other equivalent material.

N 200 Gangway and access201 An efficiently constructed fore and aft permanent gang-

way of sufficient strength shall be fitted on Type A ships at thelevel of the superstructure deck between the poop and the mid-ship bridge or deckhouse where fitted, or equivalent means ofaccess shall be provided to carry out the purpose of the gang-way, such as passages below deck. Elsewhere, and on Type Aships without a midship bridge, arrangements to the satisfac-tion of the Society shall be provided to safeguard the crew inreaching all parts used in the necessary work of the ship, seeCh.1 Sec.10

202 Safe and satisfactory access from the gangway levelshall be available between separate crew accommodations andalso between crew accommodations and the machinery space.

N 300 Hatchways

301 Exposed hatchways on the freeboard and forecastledecks or on the tops of expansion trunks on Type A ships shallbe provided with efficient watertight covers of steel or otherequivalent material.

N 400 Freeing arrangements

401 Type A ships with bulwarks shall have open rails fittedfor at least half the length of the exposed parts of the weatherdeck or a freeing port area, in the lower part of the bulwarks,of 33% of the total area of the bulwarks. The upper edge of thesheer strake shall be kept as low as practicable.

402 Where superstructures are connected by trunks, openrails shall be fitted for the whole length of the exposed parts ofthe freeboard deck.

(ICLL Reg.26)

DET NORSKE VERITAS


SECTION 7CORROSION PREVENTION

A. General

A 100 Definitions

101 The following definitions are used in this section:

Anode: An electrode through which direct current enters anelectrolyte.

Cathodic protection: A way of protecting a steel surface fromcorrosion by installing sacrificial anodes, in contact with thesteel in the electrochemical seawater corrosion cell.

Hard coating: A coating which chemically converts during itscuring process, normally used for new constructions, or non-convertible air drying coating which may be used for mainte-nance purposes. Hard coating can be either inorganic or organ-ic.

Guidance note:Commonly used organic "hard coatings" are epoxy based, suchas pure epoxies and coal tar epoxies. Zinc silicate primers are ex-amples of inorganic hard coatings.


Primer coat: The first coating applied in the shipyard (to dif-ferentiate it from shop-primer).

(IMO Res. A.798(19))

A 200 Documentation201 Specifications for corrosion prevention systems for wa-ter ballast tanks, comprising selection, application and mainte-nance, are to be submitted for information.

Guidance note:The Society’s involvement concerns the contents of the specifi-cation only and does not imply any approval of the surface prep-aration or coating as applied.


202 The purpose of the coating specification is to describethe scheme for selection, application and maintenance of thecorrosion prevention system. It is recommended that the sys-tem comprises of those items described in Table A1.

203 Ballast tanks’ anode distribution drawings are to be sub-mitted for approval. Such drawings shall include details of theconnections to the hull, e.g. welding details.

DET NORSKE VERITAS


B. Corrosion prevention systems

B 100 General

101 All steel surfaces except in tanks other than ballast tanksare to be protected against corrosion by paint of suitable com-position or other effective coating. Holds for dry bulk cargoeswill be specially considered. See also Ch.1 Sec.2 D203.

102 Corrosion prevention of seawater ballast tanks

This regulation applies to oil tankers and bulk carriers con-structed on or after 1 July 1998.

All dedicated seawater ballast tanks shall have an efficientcorrosion prevention system, such as hard protective coatingsor equivalent. The coatings should preferably be of a light col-our. The scheme for the selection, application and maintenanceof the system shall be approved by the Administration, basedon the Guidelines adopted by the Organization*. Where appro-priate, sacrificial anodes shall also be used.

* Refer to the Guidelines for the selection, application andmaintenance of corrosion prevention systems of dedicatedseawater ballast tanks, adopted by the Organization byresolution A.798(19).

(SOLAS Reg. II-1/3-2)

Guidance note:The Organization in this context is to be understood as IMO.


B 200 Coatings

201 Shop primers applied over areas which will subsequent-ly be welded, are to be of a quality accepted by the Society ashaving no detrimental effect on the finished weld. See «Regis-ter of Type Approved Products No.1 Non-Metallic Materials».

202 The use of aluminium paint is generally not accepted intanks for liquid cargo with flash point below 60°C, in adjacent

Table A1 Contents of coating specificationScheme for (see SOLAS Reg. II-1/3-2)

Items to be described in specification

General The yard’s owner’s and coating manufacturer’s agreement on the specification.Selection of coating 1) Coating type, material and manufacturer's data sheets concerning items 2) to 5) listed below.

2) Definition of coating system, including number of coats and minimum/maximum variation in dry film thickness.

Application of coating 3) Surface preparation, including preparation of edges and welds, and surface cleanliness standard (e.g. blast cleaning to Sa 2.5).

4) Coating manufacturer's safety data sheets.5) Maximum allowable air humidity in relation to air and steel temperatures during surface preparation

and coating application.6) Yard's control and inspection procedures *) including:

- acceptance criteria- tests/checks (e.g. surface cleanliness, film thickness, air humidity, temperature controls)- handling of deviations from specified quality.

7) Details of anodes, if used.8) Evidence of yard's experience in coating application **).

Maintenance of coating 9) Coating manufacturer's recommended procedure, preferably alternative procedures, for future maintenance of coating on the ship in operation.

Notes:

* The items listed in a) to q) should be described in the control and inspection procedures (and thus included in the coating specification) for the ship new-building.

a) Organisation of operators, inspectors, facilities, equipment and procedures.

b) Working conditions, e.g. access, stageing, illumination.

c) Conditioning of steel temperatures and relative humidity.

d) Methods of conditioning of steel temperatures and relative humidity, e.g. indoor facilities for blast cleaning and coating, heating/drying equipment, etc.

e) Storing of coating materials and abrasives.

f) Preparation of sharp edges.

g) Blast cleaning and any other surface preparation

h) Cleaning, including removal of abrasives after blast cleaning.

i) Cleanliness with respect to chloride content on surfaces to be coated, oil, weld smoke, dirt, etc.

j) Shielding off painted surfaces from blasting operations.

k) Blast cleaning equipment and type of abrasive.

l) Coating application equipment and methods.

m) Curing times for individual coats in relation to temperatures.

n) Dry film thickness of individual coats.

o) Total dry film thickness.

p) Coating repairs in case of damage, and handling of coated surfaces.

q) Installation of anodes, if specified. See B300.

** Minimum evidence will be a reference list stating (some or all) ships coated by the Yard. Other relevant evidence may be for example technical reportson the performance of coatings applied by the Yard, e.g. inspection reports on coating condition in ballast tanks after a number of years, or a qualitysystem certificate for the Yard's coating application division or subcontractor. It is essential that the evidence is acceptable to the Owner.

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ballast tanks, in cofferdams, in pump rooms or on deck abovethe mentioned spaces, nor in any other area where cargo gasmay accumulate. Paint containing aluminium may, however,be accepted in places as mentioned above, provided it has beenshown by tests that the paint will not increase the sparking haz-ard.

Guidance note:Coating containing aluminium in gas hazardous areas limited toAl maximum 10% by weight in the dry film is acceptable. Areas containing "liquid cargo with flash point below 60°C" areconsidered as "gas-dangerous" areas.


203 Regarding coating of ballast tanks, see Ch.1 Sec.2 D203.

B 300 Cathodic protection

301 The Society is to approve the fitting arrangement for ca-thodic protection of steel structures in tanks used for liquid car-go, with flash point below 60°C, with regard to safety againstfire and explosion. This approval also applies to adjacenttanks.

Guidance note:Approval of sacrificial anodes and their fastening devices is nor-mally given as a type approval. See "Register of Type ApprovedProducts No.3: Containers, Cargo Handling, Lifting Appliancesand Miscellaneous Equipment".


302 All anodes are to be attached to the structure in such away that they will remain securely fastened both initially and

during service. Fillet welds are to be continuous and have ade-quate cross section. Attachment by clamps fixed by setscrewswill normally not be accepted. Attachments by properly se-cured through-bolts or other positive locking devices mayhowever be accepted.

Anode steel cores bent and directly welded to the steel struc-ture are to be of a material complying with the requirements forgrade NV A or equivalent.

303 Tanks in which anodes are installed, are to have suffi-cient holes for the circulation of air to prevent gas from collect-ing in pockets.

304 In tanks, permanent anodes made of, or alloyed with,magnesium are not accepted. Impressed current systems arenot to be used in tanks due to development of chlorine and hy-drogen that can result in an explosion hazard. Aluminium an-odes are accepted in general. However, with regard to tanks forliquid cargo with flash point below 60°C and in adjacent bal-last tanks, aluminium anodes are to be so located that a kineticenergy of not more than 275 J is developed in event of theirloosening and becoming detached.

Guidance note:Aluminium anodes in gas-dangerous areas will be accepted whenattached to tank bottoms, on stringer decks and up to a certainheight above the tank bottom or stringer deck. The height abovethe tank bottom or stringer deck will be dependent upon anodeweight, whose maximum acceptable height in m is 28 divided bythe weight of the anode in kg. The attachment is to be arrangedso that the anodes cannot eventually become detached and fallthrough holes or scallops in stringer decks.


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SECTION 8PROTECTION OF THE CREW

A. Protection of the Crew

A 100 Guard rails

101 Efficient guard rails or bulwarks shall be fitted on all ex-posed parts of the freeboard, and superstructure and deckhousedecks. The height of the bulwarks or guard rails shall be at least1 metre from the deck, provided that where this height wouldinterfere with the normal operation of the ship, a lesser heightmay be approved if the Society is satisfied that adequate pro-tection is provided.

(ICLL Reg.25.2)

102 The openings below the lowest course of the guard railsshall not exceed 230 millimetres. The other courses shall benot more than 380 millimetres apart. In the case of ships withrounded gunwales the guard rail supports shall be placed on theflat of the deck.

(ICLL Reg.25.3)

103 Effective protection for the crew in the form of guardrails or life lines shall be provided above the deck cargo if thereis no convenient passage on or below the deck of the ship.

(ICLL Reg.25.5)

104

a) Fixed, removable or hinged stanchions shall be fittedabout 1.5 m apart.

b) At least every third stanchion shall be supported by abracket or stay.

c) Wire ropes may only be accepted in lieu of guard rails inspecial circumstances and then only in limited lengths.

d) Lengths of chain may only be accepted in lieu of guardrails if they are fitted between two fixed stanchions and/orbulwarks.

e) Wires shall be made taut by means of turnbuckles.

f) Removable or hinged stanchions shall be capable of beinglocked in the upright position.

(IACS LL47 to ICLL Reg. 25.2 and 25.3)

A 200 Gangways, walkways and passageways

201 Satisfactory means (in the form of guard rails, life lines,gangways or under deck passages etc.) shall be provided forthe protection of the crew in getting to and from their quarters,the machinery space and all other parts used in the necessarywork of the ship.

(ICLL Reg.25.4)

202 Acceptable arrangements referred to in Table E1 are de-fined as follows:

a) A well lit and ventilated under-deck passageway (clearopening 0.8 m wide, 2.0 m high) as close as practicable tothe freeboard deck, connecting and providing access to thelocations in question.

b) A permanent and efficiently constructed gangway fitted ator above the level of the superstructure deck on or as nearas practicable to the centre line of the ship, providing acontinuous platform at least 0.6 m in width and a non-slipsurface, with guard rails extending on each side through-out its length. Guardrails shall be at least 1 m high withcourses as required in 102, and supported by stanchionsspaced not more than 1.5 m; a foot-stop shall be provided.

c) A permanent walkway at least 0.6 m in width fitted at free-board deck level consisting of two rows of guard rails withstanchions spaced not more than 3 m. The number ofcourses of rails and their spacing are to be as required by102. On Type B ships, hatchway coamings not less than0.6 m in height may be regarded as forming one side of thewalkway, provided that between the hatchways two rowsof guardrails are fitted.

d) A 10 mm minimum diameter wire rope lifeline supportedby stanchions about 10 m apart,orA single handrail or wire rope attached to hatch coamings,continued and adequately supported between hatchways.

e) A permanent and efficiently constructed gangway fitted ator above the level of the superstructure deck on or as nearas practicable to the centre line of the ship:

— located so as not to hinder easy access across theworking areas of the deck;

— providing a continuous platform at least 1.0 m inwidth;

— constructed of fire resistant and non-slip material;— fitted with guard rails extending on each side through-

out its length; guard rails should be at least 1.0 m highwith courses as required by 102 and supported bystanchions spaced not more than 1.5 m.

— provided with a foot stop on each side;— having openings, with ladders where appropriate, to

and from the deck. Openings should not be more than40 m apart;

— having shelters of substantial construction set in wayof the gangway at intervals not exceeding 45 m if thelength of the exposed deck to be traversed exceeds 70m. Every such shelter should be capable of accommo-dating at least one person and be so constructed as toafford weather protection on the forward, port andstarboard sides.

f) A permanent and efficiently constructed walkway fitted atfreeboard deck level on or as near as practicable to the cen-tre line of the ship having the same specifications as thosefor a permanent gangway listed in (e) except for foot-stops. On Type B ships (certified for the carriage of liquidsin bulk), with a combined height of hatch coaming and fit-ted hatch cover of together not less than 1m in height thehatchway coamings may be regarded as forming one sideof the walkway, provided that between the hatchways tworows of guard rails are fitted.Alternative transverse locations for (c), (d) and (f) above,where appropriate:

(1) At or near centre line of ship; or fitted on hatchways at ornear centre line of ship.

(2) Fitted on each side of the ship.(3) Fitted on one side of the ship, provision being made for

fitting on either side.(4) Fitted on one side only.(5) Fitted on each side of the hatchways as near to the centre

line as practicable.

Additional requirements:

1. In all cases where wire ropes are fitted, adequate devicesare to be provided to ensure their tautness.

2. Wire ropes may only be accepted in lieu of guardrails inspecial circumstances and then only in limited lengths.

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3. Lengths of chain may only be accepted in lieu of guard-rails if fitted between two fixed stanchions.

4. Where stanchions are fitted, every 3rd stanchion is to besupported by a bracket or stay.

5. Removable or hinged stanchions shall be capable of beinglocked in the upright position.

6. A means of passage over obstructions, if any, such aspipes or other fittings of a permanent nature, should beprovided.

7. Generally, the width of the gangway or deck-level walk-way should not exceed 1.5 m.

(IACS LL50 Rev.4.1 to Reg. 25(4), 26(2), 27(7) and SOLASReg. II-1/3-3.)

Guidance note:Deviations from some or all of these requirements or alternativearrangements for such cases as ships with very high gangways(i.e. certain Gas Carriers) may be allowed subject to agreementcase by case with the relevant flag Administration.


Table E1 Protection of the crew

Type of ship Locations of access in ShipAssigned Summer Freeboard

Acceptable arrangements according to type of freeboard assigned

Type A Type B-100 Type B-60 Type B and B+

All shipsother than

Oil Tankers*Chemical

Tankers* andGas Carriers*

1.1 Access to midship quarters1.1.1 Between poop and bridge, or1.1.2 Between poop and deckhouse

containing living accommoda-tion or navigating equipment, or both.

≤ 3 000 mmabe

abe

ab

c(1)e

f(1)

ab

c(1)c(2)c(4)d(1)d(2)d(3)

ef(1)f(2)f(4)

> 3 000 mmabe

abe

ab

c(1)c(2)

ef(1)f(2)

1.2 Access to ends1.2.1 Between poop and bow (if there

is no bridge)1.2.2 Between bridge and bow, or1.2.3 Between a deckhouse contain-

ing living accommodation or navigating equipment, or both, and bow, or

1.2.4 In the case of a flush deck ves-sel, between crew accommoda-tion and the forward and after ends of ship.***

≤ 3 000 mm

ab

c(1)e

f(1)

ab

c(1)c(2)

ef(1)f(2)

ab

c(1)c(2)

ef(1)f(2)

> 3 000 mm

ab

c(1)c(2)d(1)d(2)

ef(1)f(2)

ab

c(1)d(1)

ef(1)

ab

c(1)c(2)c(4)d(1)d(2)d(3)

ef(1)f(2)f(4)

Oil Tankers*Chemical

Tankers* andGas Carriers*

2.1 Access to bow2.1.1 Between poop and bow, or2.1.2 Between a deckhouse contain-

ing living accommodation or navigating equipment, or both, and bow, or

2.1.3 In the case of a flush deck ves-sel, between crew accommoda-tion and the forward end of ship.

≤ (Af+Hs)**

ae

f(1)f(5)

> (Af+Hs)**

ae

f(1)f(2)

2.2 Access to after endIn the case of a flush deck ves-sel, between crew accommoda-tion and the after end of ship.***

as required in 1.2.4 for other types of ships

* Oil Tankers, Chemical Tankers and Gas Carriers as defined in SOLAS Reg. II-1/2.12, VII/8.2 and VII/11.2, respectively.** Af: the minimum summer freeboard calculated as type A ship regardless of the type of freeboard actually assigned. Hs: the standard height of superstruc-

ture as defined in ICLL Regulation 33*** Access to after end of ships is not applicable when crew accommodation is located aft.

Acceptable arrangements referred to in this table are given in 200.

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SECTION 9INTACT STABILITY

A. Application, Definitions and Document Requirements

A 100 Application101 All vessels are to comply with the stability requirementsof this Chapter, as applicable for the main class.

102 The requirements in this Chapter are in compliance withIMO Intact Stability Code (IMO Res. A. 749 (18)) and coverIACS UR L2.

103 For vessels with service restrictions as described in Pt.1Ch.1 Sec.2 B400, modified stability requirements may be con-sidered if consistent with the applicable service restriction.

104 Vessels with additional class notations are to complywith additional stability requirements as given in the appropri-ate rule chapters.

105 Ships with loading computer systems intended for sta-bility control are to comply with Pt.6 Ch.9 Sec.1 A200.

A 200 Terms201 External watertight integrity

The capability of the hull structure and its external closing ap-pliances to prevent downflooding to volumes assumed buoy-ant. The external watertight integrity includes position andtype of closing appliances, alarms, indicators, remote controlsand signboards fitted to such appliances.

202 Weathertight

Weathertight means that in any sea conditions water will notpenetrate into the ship.

203 Watertight

Capable of preventing ingress of water during static submer-sion under a head of water for which the surrounding structureis designed.

A watertight closing appliance is also considered weathertight.

204 Downflooding

Ingress of water through external openings to buoyancy vol-umes.

205 Downflooding angle related to intact stability

The minimum heel angle where an external opening withoutweathertight closing appliance is submerged.

206 Lightweight

Lightweight is the displacement of a ship in tonnes withoutcargo, fuel, lubricating oil, ballast water, fresh water and feedwater in tanks, consumable stores, and passengers and crewand their effects.

The lightweight definition stated in the Stability Manual indi-cates which items are included or not included in the light-weight.

Guidance note:The approved lightweight data are the data which are approvedfor the purpose of stability approval and control but not necessar-ily for determination of the deadweight.


207 Maximum allowable vertical centre of gravity

The maximum vertical centre of gravity of the vessel, correct-ed for free surface effect, which complies with the stipulatedstability requirements for the draught in question.

208 Preliminary stability documentation

The stability documentation which is based on estimated light-weight data.

209 Final stability documentation

The stability documentation which is based on approved light-weight data obtained from an inclining test or lightweight sur-vey.

A 300 Documentation for approval301 The following documentation is to be submitted for ap-proval:

— preliminary stability booklet— inclining test procedure— inclining test report— final stability booklet.

302 All stability documentation submitted for approval is tohave a unique identification, i.e.:

— name and identity no. of ship— date of issue— revision number and date, if applicable— name of originator— table of contents (reports only)— consecutive page numbering (reports only).

303 For each sister vessel, it is sufficient to submit:

— lightweight survey procedure (inclining test procedure forpassenger vessels)

— lightweight survey report (or inclining test report for pas-senger vessels)

— final stability booklet.

304 If the assignment of class is to be based on the approvalof the Flag Administration according to Pt.1 Ch.1 Sec.3A1200, a copy of the final stability documentation stamped bythe Flag Administration and the approval letter issued by theFlag Administration are to be submitted to the Society.


306 The following documentation is to be submitted for in-formation:

— general arrangement— body plan, lines plan or offset table— external watertight integrity plan or freeboard plan.

Guidance note:Details of the documentation are given in Classification NoteNo. 20.1 «Stability Documentation — Ships Newbuildings».


B. Surveys and Tests

B 100 General101 The following surveys and tests are to be carried out:

— external watertight integrity survey with respect to unpro-tected and protected openings together with their closingappliances, alarms, indicators and signboards, normallycovered by the load line initial survey

— checking of draft marks— remote draft measurement and tank gauging systems

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— inclining test or lightweight survey.

C. General Requirements

C 100 Stability book

101 An approved stability booklet is to be provided onboard.The stability booklet is to include information as is necessaryto enable the master by a rapid and simple process to obtain ac-curate guidance as to the stability of the ship under varyingconditions of service.

Guidance note:The format and content of the stability book is further describedin Classification Note No. 20.1 and IACS UI LL61.


102 Stability data and associated plans are to include a trans-lation into English, if English is not used as official language.

C 200 Fixed Ballast

201 If used, fixed ballast is to be installed in a manner thatprevents shifting of position.

C 300 Draught Marks

301 The ship is to have scale of draught marks at the bow andstern on both port and starboard side.

Guidance note:The draught marks should reflect the extreme draught at the lo-cation where they are fitted. The stability manual should containguidance on, from draught mark readings, how to utilise the sta-bility information contained therein. Norwegian StandardNS6301 may be referenced for further guidelines on the size andlocation of draught marks.

C 400 Loading Computer System

401 Loading computers for stability calculation are to beconsidered as supplementary to the approved stability booklet.

402 Loading computers for stability control are to complywith Pt.6 Ch.9.

D. Intact Stability Criteria

D 100 General stability criteria

101 The following criteria are given for all ships:

— The area under the righting lever curve (GZ curve) is notto be less than 0.055 metre-radians up to θ = 30° angle ofheel and not less than 0.09 metre-radians up to θ = 40° orthe angle of flooding θ f if this angle is less than 40°. Ad-ditionally, the area under the righting lever curve betweenthe angles of heel of 30° and 40° or between 30° and θf, ifthis angle is less than 40°, is not to be less than 0.03 metre-radians.

— The righting lever (GZ) is to be at least 0.20 m at an angleof heel equal to or greater than 30°.

— The maximum righting lever should occur at an angle ofheel preferably exceeding 30° but not less than 25°.

— The initial metacentric height, GM0 is not to be less than0.15 m.

Guidance note:For ships carrying timber deck cargoes and provided that:

- the cargo extends longitudinally between superstructures end,or where there is no limiting superstructure at the after end,the timber deck cargo shall extend at least to the after end ofthe aftermost hatchway

- the cargo extends transversely for the full beam of the ship af-ter due allowance for a rounded gunwale not exceeding 4% ofthe breadth of the ship

- supporting uprights are secured and remain securely fixed atlarge angles of heel

the following criteria may be used instead of the criteria in 101:

- the area under the righting lever curve (GZ curve) should notbe less than 0.08 metre-radians up to θ = 40° angle of heel orthe angle of flooding θf if this angle is less than 40°

- the maximum value of the righting lever (GZ) should be atleast 0.25 m

- at all times during the voyage, the metacentric height GM0should be positive after correction for the free surface effectsof liquid in tanks and, where appropriate, the absorption ofwater by the deck cargo and/or ice accretion on the exposedsurfaces. Additionally, in the departure condition, the meta-centric height GM0 should not be less than 0.10 m.


102 The following equivalent criteria are recommendedwhere a vessel's characteristics render compliance with 101impracticable (based on IMO Res. A. 749 (18), Ch.4.5.6):

— The area under the curve of righting levers (GZ curve)should not be less than 0.070 metre-radians up to an angleof 15° when the maximum righting lever (GZ) occurs at15° and 0.055 metre-radians up to an angle of 30° whenthe maximum righting lever (GZ) occurs at 30° or above.Where the maximum righting lever (GZ) occurs at anglesof between 15° and 30°, the corresponding area under therighting lever curve should be:

0.055 + 0.001 (30° - θmax) metre-radianswhere θmax is the angle of heel in degrees at which therighting lever curve reaches its maximum.

— The area under the righting lever curve (GZ curve) be-tween the angles of heel of 30° and 40°, or between 30°and θf this angle is less than 40°, should be not less than0.03 metre-radians.

— The righting lever (GZ) should be at least 0.20 m at an an-gle of heel equal to or greater than 30°.

— The maximum righting lever (GZ) should occur at an an-gle of heel not less than 15°.

— The initial transverse metacentric height (GM0) should notbe less than 0.15 m.

103 When anti-rolling devices are installed in a ship, the ap-plicable intact stability criteria are to be satisfied when the de-vices are in operation.

104 For certain ship types additional or alternative intact anddamage stability criteria have been specified. These vessels (orclass notations) are given in Table D1.

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D 200 Weather criterion

201 For ships with large windage area, such as passenger,container and Ro/Ro ships, the criteria listed below are to becomplied with (based on IMO Res. A. 749 (18), Ch.3.2):

1 The ability of a ship to withstand the combined effects ofbeam wind and rolling should be demonstrated for each stand-ard condition of loading, with reference to the Fig. 1 as fol-lows:

1.1 - the ship is subjected to a steady wind pressure acting per-pendicular to the ship's centreline which results in a steadywind heeling lever

1.2 - from the resultant angle of equilibrium (θ0), the ship is as-sumed to roll owing to wave action to an angle of roll (θ1) towindward. Attention should be paid to the effect of steadywind so that excessive resultant angles of heel are avoided.

The angle of heel under action of steady wind (θ0) should belimited to a certain angle to the satisfaction of the Society. Asa guide, 16° or 80% of the angle of deck edge immersion,whichever is less, is suggested.

1.3 - the ship is then subjected to a gust wind pressure whichresults in a gust wind heeling lever

1.4 - under these circumstances, area "b" should be equal to or

Table D1 Stability design requirements for different ship types and class notationsClass notation / Ship type Intact Damage Class Requirement IMO Reference1A1 X D101 IMO Res. A. 749 (18), Ch.3.11A1, offshore/harbour service vessels X D102 IMO Res. A. 749 (18), Ch.4.51A1, wind X D201 IMO Res. A. 749 (18), Ch.3.21A1, timber X D101 IMO Res. A. 749 (18), Ch.4.1

Cargo vessels

Freeboard Type A, B-60, B-100 X E103 ICLL 1966 Reg. 27 as amended by the 1988 Proto-col

* Cargo vessels, L > 80 m X E102 SOLAS 74/78 Ch. II-1, B-1Tanker for Oil X

XPt.5 Ch.3 Sec.3 APt.5 Ch.3 Sec.3 A

MARPOL 73/78 Reg. 25 A MARPOL 73/78 Reg. 25 and 13F

Tanker for Chemicals X Pt.5 Ch.4 Sec.3 A IMO IBC Code, Ch.2Tanker for Liquefied Gas X Pt.5 Ch.5 Sec.3 A IMO IGC Code, Ch.2

Offshore/Harbour service vessels Supply Vessel X Pt.5 Ch.7 Sec.3 D IMO Res. A. 469 (XII) Ch.2SF X

XPt.5 Ch.7 Sec.4 A102Pt.5 Ch.7 Sec.4 B

IMO Res. A. 469 (XII) Ch.3

Tug X Pt.5 Ch.7 Sec.2 E No IMO requirementsFire Fighter I (or II or III) X Pt.5 Ch.7 Sec.5 I No IMO requirementsCRANE X Pt.6 Ch.1 Sec.3 E No IMO requirementsCRANE VESSEL X

XPt.5 Ch.7 Sec.8 D200Pt.5 Ch.7 Sec.8 D100

No IMO requirements IMO Res. A. 534 (13) or SOLAS 73/78 Ch.II-1, B-1

DSV-I/II/III SF (diving support vessel) X X Pt.6 Ch.1 Sec.4 H IMO Res. A. 469 (XII)DEICE (de-icing/anti icing vessels) X X Pt.6 Ch.1 Sec.5 B IMO Res. A. 469 (XII)

Offshore vessels Drilling Vessel X X Pt.5 Ch.7 Sec.6 E IMO MODU Code 1989, Ch.3Pipe Laying Vessel X X Pt.5 Ch.7 Sec.7 E IMO Res. A. 534 (13) or SOLAS 73/78 Ch.II-1, B-1Well Stimulation Vessel X X Pt.5 Ch.7 Sec.10 H IMO Res. A. 469 (XII)Cable Laying Vessel X

XPt.5 Ch.7 Sec.17 E IMO Res. A. 534 (13) or SOLAS 73/78 Ch.II-1, B-1

Escort (n, V) X Pt.5 Ch.7 Sec.16 D No IMO requirementsStandby Vessel X

XPt.5 Ch.7 Sec.18 E No IMO requirements

Other vessels

Passenger Ship XX

Pt.5 Ch.2 Sec.2 F300Pt.5 Ch.2 Sec.2 F400

IMO Res. A. 749 (18), Ch.3.1.2.6 SOLAS 74/78 Ch. II-1, B

Car Ferry, Train Ferry or Car and Train Ferry

XX

Pt.5 Ch.2 Sec.3 F101 IMO Res. A. 749 (18) Ch.3.1.2.6SOLAS 74/78 Ch.II-1, B

Fishing Vessel or Stern Trawler

X Pt.5 Ch.6 Sec.1 F To cover IMO Res. A. 749 (18), Ch.4.2Torremolinos International Conference Ch.III mod-ified by the Torremolinos Protocol of 1993

Icebreaker / POLAR XX

Pt.5 Ch.1 Sec.4 L400Pt.5 Ch.1 Sec.4 L500

No IMO requirements No IMO requirements

Barge for Deck Cargo X Pt.5 Ch.7 Sec.15 I IMO Res. A. 749 (18), Ch.4.7

lw1( )

lw2( )

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greater than area "a";

1.5 - free surface effects should be accounted for in the stand-ard conditions of loading as set out in D301.

Fig. 1Severe wind and rolling

The angles in Fig. 1 are defined as follows:

θo = angle of heel under action of steady wind (see 1.2 and3)

θ1 = angle of roll to windward due to wave actionθ2 = angle of downflooding (θf) or 50° or θc whichever is

less, where:θf = angle of heel at which openings in the hull, superstruc-

tures or deckhouses which cannot be closed weather-tight immerse. In applying this criterion, smallopenings through which progressive flooding cannottake place need not be considered as open.

θc = angle of second intercept between wind heeling lever and GZ curves.

2 The wind heeling levers and referred to in 1.1and 1.3 are constant values at all angles of inclination andshould be calculated as follows:

P = 504 N/m2 (wind speed = 29 m/s). The value of P, usedfor ships in restricted service and/or for ships with verylarge windage areas (due to coherence length for windspeed), may be reduced subject to the approval of theSociety

A = projected lateral area of the portion of the ship anddeck cargo above the waterline (m2)

Z = vertical distance from the centre of A to the centre ofthe underwater lateral area or approximately to a pointat one half the draught (m)

disp = displacement (t)g = 9.81 m/s2

The angle of roll θ1 1) referred to in 1.2 should be calculated as

follows:

1) The angle of roll for ships with anti-rolling devices should be determinedwithout taking into account the operation of these devices.

X1 = factor as shown in Table D2X2 = factor as shown in Table D3

k = 1.0 for round-bilged ship having no bilge or bar keels = 0.7 for a ship having sharp bilges = as shown in Table D4 for a ship having bilge keels, a

bar keel or bothr = 0.73 ± 0.6 OG/d, with: OG = distance between the centre of gravity and the water-

line (m) (+ if centre of gravity is above the waterline, -if it is below)

d = mean moulded draught of the ship (m)s = factor as shown in Table D5.

(Intermediate values in Tables A2 to A5 should be obtained bylinear interpolation).

Rolling period

C = 0.373 + 0.023 (B/d) - 0.043 (L/100)

The symbols in Tables D2 to D5 and the formula for the rollingperiod are defined as follows:

L = waterline length of the ship (m)B = moulded breadth of the ship (m)d = mean moulded draught of the ship (m)

lw2( )

lw1( ) lw2

( )

lw1

PAZ1000 g disp------------------------------- (m) and=

lw21.5lw1

(m)=

θ1 109kX1X2 rs (degrees)=

Table D2 Values of factor X1

B/d X1≤ 2.4

2.52.62.72.82.93.03.13.23.33.4

≥ 3.5

1.00.980.960.950.930.910.900.880.860.840.820.80

Table D3 Values of factor X2

Cb X2≤ 0.45

0.500.550.600.65

≥ 0.70

0.750.820.890.950.971.0

Table D4 Values of factor k

k

01.01.52.02.53.03.5

≥ 4.0

1.050.980.950.880.790.740.720.70

Table D5 Values of factor sT s

< 678

12141618

≥ 20

0.1000.0980.0930.0650.0530.0440.0380.035

Ak100

LB----------------

T2 C B

GM-------------- (seconds)=

DET NORSKE VERITAS


Cb = block coefficientAk = total overall area of bilge keels, or area of the lateral

projection of the bar keel, or sum of these areas (m2)GM = metacentric height corrected for free surface effect

(m).

202 Other calculation methods of equivalent safety levelmay be accepted as an alternative to the above.

Guidance note:For some ships, the formulas may over-estimate the roll angle.As an alternative, the roll angle can be determined by model testsor direct calculations carried out for sea-states corresponding tothe recommended wind speed.

D 300 Assumptions concerning intact stability criteria and calculations

301 For all loading conditions the initial metacentric heightand the stability curves shall be corrected for the effect of freesurface of liquid in tanks.

Guidance note:The free surface should be taken into account as described in theIACS UI LL61.


302 Compliance with the stability criteria is to be checkedfor the main loading conditions intended by the owner in re-spect of the vessel's operation.

303 If the owner does not supply sufficiently detailed infor-mation regarding such loading conditions, calculations shall bemade for the standard loading conditions in 304 and 305.

304 The following standard loading conditions apply to car-go ships:

— ship in the fully loaded departure condition, with cargo ho-mogeneously distributed throughout all cargo spaces andwith full stores and fuel

— ship in the fully loaded arrival condition, with cargo ho-mogeneously distributed throughout all cargo spaces andwith 10% stores and fuel remaining

— ship in ballast in departure condition, without cargo butwith full stores and fuel

— ship in ballast in arrival condition, without cargo and with10% stores and fuel remaining.

305 The following additional loading conditions apply tocargo ships intended to carry deck cargoes:

— ship in the fully loaded departure condition with cargo ho-mogeneously distributed in the holds and with cargo spec-ified in extension and weight on deck, with full stores andfuel

— ship in the fully loaded arrival condition with cargo homo-geneously distributed in the holds and with cargo specifiedin extension and weight on deck, with 10% stores and fuel.

306 In the fully loaded departure conditions in 304 and 305the ship is to be assumed loaded to the summer load waterline,or if intended to carry timber deck cargo, to the summer timberload line. The water ballast tanks should normally be assumedempty.

307 In all cases, the cargo in holds is assumed fully homoge-neous unless this is inconsistent with the practical service ofthe ship.

308 Where timber deck cargoes are carried, the amount ofcargo and ballast is to correspond to the worst service condi-tion in which all the stability criteria in D100 are met. In thearrival condition it is to be assumed that the weight of the deckcargo has increased by 10% due to water absorption.

309 In all cases, when deck cargo is carried, a realistic stow-age weight is to be assumed and stated, including the height ofthe cargo.

Guidance note:For ships carrying timber deck cargoes conditions should beshown indicating the maximum permissible amount of deck car-go having regard to the lightest stowage rate likely to be met inservice.


310 Only those parts of the ship that are adequately protectedby weathertight closing are accepted included as buoyant in thestability calculations.

Guidance note:Reference is made to IMO Intact Code IMO Res. A. 749(18), Ch.3.6 and the IACS UI LL62.


311 The Society may allow account to be taken in stabilitycalculations of the buoyancy of the deck cargo assuming thatsuch cargo has a permeability of 0.25.

E. Damage Stability

E 100 Damage stability

101 Vessels with additional class notations shall complywith the additional damage stability requirements as given inthe appropriate rule chapters.

102 Cargo ships of 80 m in length (Ls) and upwards shallcomply with the damage stability requirements according toSOLAS Ch.II-1, Part B-1. Cargo ships that have to complywith other mandatory damage stability regulations, see thefootnote of SOLAS Ch.II-1, Part B-1, may be excluded fromthe application.

103 Ships having a reduced freeboard type A or reduced B-freeboard shall comply with Regulation 27 of the InternationalLoad Line Convention.

F. Determination of Lightweight Data

F 100 Application

101 Every passenger ship and cargo ship shall be inclinedupon its completion and the lightweight displacement and cen-tre of gravity determined.

102 The inclining test required in 101 may be dispensed withprovided basic stability data are available from the inclinationtest of a sister ship and it is shown to the satisfaction of the So-ciety that reliable stability information for the exempted shipcan be obtained from such basic data.

Guidance note:Dispensation according to 102 is not considered applicable topassenger ships and other ships where the lightweight is morethan 75% of the total displacement.


F 200 Procedure

201 The inclining test is to be carried out according to the ap-proved test procedure and in the presence of the Society's rep-resentative.

Guidance note:A surveyor of the Society need not attendt the test if a represent-ative of the Flag Authority is witnessing the test.

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Guidelines for conducting inclining test or lightweight survey aregiven in Classification Note No. 20.2 «Lightweight Determina-tion — Ships (Inclining Test and Lightweight Survey)».


202 The inclining test report shall be signed by the person re-sponsible for the test and by the Society's representative.

203 The approved lightweight and centre of gravity shall beused in the final stability booklet.

F 300 Lightweight Survey301 A lightweight survey shall be carried out if an incliningtest has been dispensed with according to 102.

302 In case structural strength limitations etc. make it impos-sible to perform an inclining test, a lightweight survey may beaccepted provided a detailed lightweight estimate includingVCG is worked out in advance and the estimate compared withthe result of the lightweight survey. If the lightweight surveyreveals a deviation of lightweight data from the estimate, thedeviation is assumed to be at the most unfavourable positionwhen calculating the vertical centre of gravity.

303 If, compared with the sister ship, the lightweight surveyreveals a lightweight displacement deviation exceeding 2% oran LCG deviation exceeding 1% of the length of the ship, aninclining test may be required.

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SECTION 10FIRE SAFETY

A. Scope

A 100 General

101 When references are given to SOLAS, this is to be takenas SOLAS 74 including amendments as in force per 1 July2002.

102 Fire technical requirements to specific types of vesselare covered by the Parts and Chapters for the relevant addition-al class notations, as referred to in B201.

B. Classification

B 100 Application

101 The requirements of this section apply to all ships as-signed main class, except as specified in 102.

102 This section, unless expressly provided otherwise, doesnot apply to:

— ships of war and troopships— cargo ships less than 500 gross tonnage— ships not propelled by mechanical means— wooden ships of primitive build— pleasure yachts not engaged in trade— fishing vessels.

(SOLAS Reg. I/3)

See also 104 concerning cargo ships less than 500 gross ton-nage.

103 Consideration will be given to ships classed for restrict-ed or special service.

(SOLAS Reg. II-2/1.4.1)

104 For cargo ships less of less than 500 gross tonnage, sub-section H will apply.

B 200 Rule references201 Special requirements applicable to additional class nota-tions are placed under:

C. Definitions

C 100 Definitions

101 Accommodation spaces are those spaces used for publicspaces, corridors, lavatories, cabins, offices, hospitals, cine-mas, game and hobby rooms, barber shops, pantries containingno cooking appliances and similar spaces.


102 " A” class divisions are those divisions formed by bulk-heads and decks which comply with the following:

.1 they are constructed of steel or other equivalent material;

.2 they are suitably stiffened;

.3 they are insulated with approved non-combustible materi-als such that the average temperature of the unexposedside will not rise more than 140°C above the original tem-perature, nor will the temperature, at any one point, in-cluding any joint, rise more than 180°C above the originaltemperature, within the time listed below:

— class "A-60" 60 minutes— class "A-30" 30 minutes— class "A-15" 15 minutes— class "A-0" 0 minutes.

.4 they are so constructed as to be capable of preventing thepassage of flame to the end of the first half hour of thestandard fire test;

.5 the Society shall require a test of a prototype bulkhead ordeck in accordance with the Fire Test Procedures Code toensure that it meets the above requirements for integrityand temperature rise.


103 Atriums are public spaces within a single main verticalzone spanning three or more open decks.


104 "B” class divisions are those divisions formed by bulk-heads, decks, ceilings or linings which comply with the follow-ing:

.1 they are constructed of approved non-combustible materi-als and all materials entering into the construction anderection of "B" class divisions shall be non-combustible,with the exception that combustible veneers may be per-mitted provided they meet other requirements of this sec-tion

.2 they have an insulation value such that the average tem-perature of the unexposed side will not rise more than140°C above the original temperature, nor will the tem-perature at any one point, including any joint, rise morethan 225°C above the original temperature, within thetime listed below:

— class "B-15" 15 minutes— class "B-0" 0 minutes

.3 they are so constructed as to be capable of preventing thepassage of flame to the end of the first half hour of thestandard fire test

.4 the Society shall require a test of a prototype division inaccordance with the Fire Test Procedures Code to ensurethat it meets the above requirements for integrity and tem-perature rise.


105 Bulkhead deck is the uppermost deck up to which thetransverse watertight bulkheads are carried.


106 Cargo area is that part of the ship that contains cargoholds, cargo tanks, slop tanks and cargo pump-rooms includ-ing pump-rooms, cofferdams, ballast and void spaces adjacentto cargo tanks and also deck areas throughout the entire lengthand breadth of the part of the ship over the above-mentionedspaces.


Passenger Ships Pt.5 Ch.2Oil Carriers Pt.5 Ch.3Chemical Carriers Pt.5 Ch.4Liquefied Gas Carriers Pt.5 Ch.5Fishing Vessels Pt.5 Ch.6Fire Fighter I (or II or III) Pt.5 Ch.7Carriage of Dangerous Goods Pt.5 Ch.11Additional Fire Protection (F-AMC) Pt.6 Ch.4

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107 A cargo ship is any ship which is not a passenger ship.

(SOLAS Reg. I/2(g))

108 Cargo spaces are spaces used for cargo, cargo oil tanks,tanks for other liquid cargo and trunks to such spaces.


109 Central control station is a control station in which thefollowing control and indicator functions are centralized:

.1 fixed fire detection and alarm system;

.2 automatic sprinklers, fire detection and alarm system;

.3 fire door indicator panels;

.4 fire door closures;

.5 watertight door indicator panels;

.6 watertight door closure;

.7 ventilation fans;

.8 general/fire alarms;

.9 communication systems including telephones; and

.10 microphones to public address systems.


110 "C” class divisions are divisions constructed of ap-proved non-combustible materials. They need meet neither re-quirements relative to the passage of smoke and flame norlimitations relative to the temperature rise. Combustible ve-neers are permitted provided they meet other requirements ofthis Chapter.


111 A division consisting of a non-combustible core andcombustible veneers may be accepted as a B or C class divi-sion, provided that the non-combustible core is tested in ac-cordance with the Fire Test Procedures Code, part 1, that the Bclass division is tested in accordance with the Fire Test Proce-dures Code, part 3, and that the veneers mounted to the non-combustible core are tested in accordance with the Fire TestProcedures Code, part 5 and part 2 if applicable.

(IACS UI SC125)

112 Chemical tanker is a cargo ship constructed or adaptedand used for the carriage in bulk of any liquid product of aflammable nature listed in chapter 17 of the International BulkChemical Code, as defined in regulation VII/8.1.


113 Closed ro-ro spaces are ro-ro spaces which are neitheropen ro-ro spaces nor weather decks.


114 Closed vehicle spaces are vehicle spaces which are nei-ther open vehicle spaces nor weather decks.


115 Combination carrier is a cargo ship designed to carryboth oil and solid cargoes in bulk.


116 Combustible material is any material other than a non-combustible material.


117 Continuous “B” class ceilings or linings are those "B"class ceilings or linings which terminate at an "A" or "B" classdivision.


118 Continuously manned central control station is a centralcontrol station which is continuously manned by a responsiblemember of the crew.


119 Control stations are those spaces in which the ship's ra-dio or main navigating equipment or the emergency source ofpower is located or where the fire recording or fire control

equipment is centralised. Spaces where the fire recording orfire control equipment is centralised are also considered to bea fire control station.


Control stations are spaces containing emergency sources foremergency lighting, wheel house and chartroom, spaces con-taining the ship's radio equipment, fire extinguishing rooms.Spaces containing the following battery sources are to be re-garded as control stations regardless of battery capacity:

.1 emergency batteries in separate battery room for powersupply from blackout till start of emergency generator;

.2 emergency batteries in separate battery room as reservesource of energy to radiotelegraph installation;

.3 batteries for start of emergency generator;

.4 and in general, all emergency batteries required in pursu-ance of Pt.4 Ch.8 Sec.2 C.

(IACS UI SC17)

120 Crude oil is any oil occurring naturally in the earthwhether or not treated to render it suitable for transportationand includes crude oil where certain distillate fractions mayhave been removed from or added to.


121 Dangerous goods are those goods referred to in regula-tion VII/2.


122 Deadweight is the difference in tonnes between the dis-placement of a ship in water of a specific gravity of 1.025 at theload water-line corresponding to the assigned summer free-board and the lightweight of the ship.


123 Fire Safety Systems Code means the International Codefor Fire Safety Systems as adopted by the Maritime SafetyCommittee of the Organization by resolution MSC.98(73), asmay be amended by the Organization, provided that suchamendments are adopted, brought into force and take effect inaccordance with the provisions of article VIII of the presentConvention concerning the amendment procedures applicableto the annex other than chapter I thereof.


124 Fire Test Procedures Code means the InternationalCode for Application of Fire Test Procedures as adopted by theMaritime Safety Committee of the Organization by resolutionMSC.61(67), as may be amended by the Organization, provid-ed that such amendments are adopted, brought into force andtake effect in accordance with the provisions of article VIII ofthe present Convention concerning the amendment proceduresapplicable to the annex other than chapter I thereof.


125 Flashpoint is the temperature in degrees Celsius (closedcup test) at which a product will give off enough flammablevapour to be ignited, as determined by an approved flashpointapparatus.


126 Gas carrier is a cargo ship constructed or adapted andused for the carriage in bulk of any liquefied gas or other prod-ucts of a flammable nature listed in chapter 19 of the Interna-tional Gas Carrier Code, as defined in regulation VII/11.1.


127 Helideck is a purpose-built helicopter landing area locat-ed on a ship including all structure, fire-fighting appliancesand other equipment necessary for the safe operation of heli-copters.


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128 Helicopter facility is a helideck including any refuellingand hangar facilities.


129 Lightweight is the displacement of a ship in tonnes with-out cargo, fuel, lubricating oil, ballast water, fresh water andfeedwater in tanks, consumable stores, and passengers andcrew and their effects.


130 Low flame-spread means that the surface thus describedwill adequately restrict the spread of flame, this being deter-mined in accordance with the Fire Test Procedures Code.


131 Machinery spaces are machinery spaces of category Aand other spaces containing propulsion machinery, boilers, oilfuel units, steam and internal combustion engines, generatorsand major electrical machinery, oil filling stations, refrigerat-ing, stabilising, ventilation and air conditioning machinery,and similar spaces, and trunks to such spaces.


132 Machinery spaces of category A are those spaces andtrunks to such spaces which contain either:

.1 internal combustion machinery used for main propulsion;

.2 internal combustion machinery used for purposes otherthan main propulsion where such machinery has in the ag-gregate a total power output of not less than 375 kW; or

.3 any oil-fired boiler or oil fuel unit, or any oil-fired equip-ment other than boilers, such as inert gas generators, in-cinerators, etc.


Spaces which contain oil fired equipment other than boilers,such as inert gas generators, incinerators, waste disposal unitsetc., are to be considered as machinery spaces of category A.

(IACS UR F35 / UI SC15)

133 Main vertical zones are those sections into which thehull, superstructure and deckhouses are divided by "A" classdivisions, the mean length and width of which on any deckdoes not in general exceed 40 m.


134 Non-combustible material is a material which neitherburns nor gives off flammable vapours in sufficient quantityfor self-ignition when heated to approximately 750°C, this be-ing determined in accordance with the Fire Test ProceduresCode.


135 Oil fuel unit is the equipment used for the preparation ofoil fuel for delivery to an oil-fired boiler, or equipment used forthe preparation for delivery of heated oil to an internal combus-tion engine, and includes any oil pressure pumps, filters andheaters dealing with oil at a pressure of more than 0.18 N/mm2.


Oil fired inert gas generators are to be defined as Oil fuel unit.

(IACS UI SC16)

136 Open ro-ro spaces are those ro-ro spaces that are eitheropen at both ends or have an opening at one end, and are pro-vided with adequate natural ventilation effective over their en-tire length through permanent openings distributed in the sideplating or deckhead or from above, having a total area of atleast 10% of the total area of the space sides.


137 Open vehicle spaces are those vehicle spaces either openat both ends, or have an opening at one end and are providedwith adequate natural ventilation effective over their entirelength through permanent openings distributed in the side plat-

ing or deckhead or from above, having a total area of at least10% of the total area of the space sides.


138 A passenger ship is a ship which carries more thantwelve passengers.

(SOLAS Reg. I/2(f))

139 Prescriptive requirements means the construction char-acteristics, limiting dimensions, or fire safety systems speci-fied in the Rules.


140 Public spaces are those portions of the accommodationwhich are used for halls, dining rooms, lounges and similarpermanently enclosed spaces.


141 Rooms containing furniture and furnishings of restrictedfire risk, are those rooms containing furniture and furnishingsof restricted fire risk (whether cabins, public spaces, offices orother types of accommodation) in which:

.1 case furniture such as desks, wardrobes, dressing tables,bureaux, dressers, are constructed entirely of approvednon-combustible materials, except that a combustible ve-neer not exceeding 2 mm may be used on the working sur-face of such articles;

.2 free-standing furniture such as chairs, sofas, tables, areconstructed with frames of non-combustible materials;

.3 draperies, curtains and other suspended textile materialshave qualities of resistance to the propagation of flame notinferior to those of wool having a mass of mass 0.8 kg/m2,this being determined in accordance with the Fire TestProcedures Code;

.4 floor coverings have low flame-spread characteristics;

.5 exposed surfaces of bulkheads, linings and ceilings havelow flame-spread characteristics;

.6 upholstered furniture has qualities of resistance to the ig-nition and propagation of flame, this being determined inaccordance with the Fire Test Procedures Code; and

.7 bedding components have qualities of resistance to the ig-nition and propagation of flame, this being determined inaccordance with the Fire Test Procedures Code.


142 Ro-ro spaces are spaces not normally subdivided in anyway and normally extending to either a substantial length orthe entire length of the ship in which motor vehicles with fuelin their tanks for their own propulsion and/or goods (packagedor in bulk, in or on rail or road cars, vehicles (including road orrail tankers), trailers, containers, pallets, demountable tanks orin or on similar stowage units or other receptacles) can be load-ed and unloaded normally in a horizontal direction.


143 Ro-ro passenger ship means a passenger ship with ro-rospaces or special category spaces.


144 Steel or other equivalent material means any non-com-bustible material which, by itself or due to insulation provided,has structural and integrity properties equivalent to steel at theend of the applicable exposure to the standard fire test (e.g. alu-minium alloy with appropriate insulation).


145 Sauna is a hot room with temperatures normally varyingbetween 80°- 120°C where the heat is provided by a hot sur-face (e.g. by an electrically-heated oven). The hot room mayalso include the space where the oven is located and adjacentbathrooms.


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146 Service spaces are those spaces used for galleys, pantriescontaining cooking appliances, lockers, mail and specierooms, storerooms, workshops other than those forming part ofthe machinery spaces, and similar spaces and trunks to suchspaces.


147 Special category spaces are those enclosed vehicle spac-es above and below the bulkhead deck, into and from whichvehicles can be driven and to which passengers have access.Special category spaces may be accommodated on more thanone deck provided that the total overall clear height for vehi-cles does not exceed 10 m.


148 A standard fire test is a test in which specimens of therelevant bulkheads or decks are exposed in a test furnace totemperatures corresponding approximately to the standardtime-temperature curve in accordance with the test methodspecified in the Fire Test Procedures Code.


149 A tanker is a cargo ship constructed or adapted for thecarriage in bulk of liquid cargoes of an inflammable nature.

(SOLAS Reg. I/2(h))

150 Vehicle spaces are cargo spaces intended for carriage ofmotor vehicles with fuel in their tanks for their own propul-sion.


151 Weather deck is a deck which is completely exposed tothe weather from above and from at least two sides.


D. Documentation

D 100 Plans and particulars

101 The following plans and particulars are to be submittedfor approval:

— arrangement of means of escape including stairways, es-cape trunks, escape ladders, primary and secondary es-capes, assembly/muster stations and embarkation areas.

102 The following plan is to be submitted for information:

— fire control plan.

E. Protection of Stairways and Lift Trunks

E 100 Protection of stairways and lift trunks in accom-modation spaces, service spaces and control stations

(SOLAS Reg. II-2/9.2.3.4)

101 Stairways which penetrate only a single deck shall beprotected, at a minimum, at one level by at least "B-0" class di-visions and self-closing doors. Lifts which penetrate only asingle deck shall be surrounded by "A-0" class divisions withsteel doors at both levels. Stairways and lift trunks which pen-etrate more than a single deck shall be surrounded by at least"A-0" class divisions and be protected by self-closing doors atall levels.

102 On ships having accommodation for 12 persons or less,where stairways penetrate more than a single deck and wherethere are at least two escape routes direct to the open deck atevery accommodation level, the "A-0" requirements of 101may be reduced to "B-0".

F. Means of Escape

F 100 Purpose(SOLAS Reg. II-2/13.1)

101 The purpose of these rules are to provide means of es-cape so that persons onboard can safely and swiftly escape tothe lifeboat and liferaft embarkation deck. For this purpose, thefollowing functional requirements shall be met:

.1 safe escape routes shall be provided;

.2 escape routes shall be maintained in a safe condition, clearof obstacles; and

.3 additional aids for escape shall be provided as necessaryto ensure accessibility, clear marking, and adequate de-sign for emergency situations.

F 200 General(SOLAS Reg. II-2/13.2)

201 Unless expressly provided otherwise, at least two widelyseparated and ready means of escape shall be provided from allspaces or group of spaces.

202 Lifts shall not be considered as forming one of the re-quired means of escape.

F 300 Means of escape from accommodation spaces, service spaces and control stations(SOLAS Reg. II-2/13.3.1 and 13.3.3)

301 Stairways and ladders shall be so arranged as to provideready means of escape to the lifeboat and liferaft embarkationdeck from passenger and crew accommodation spaces andfrom spaces in which the crew is normally employed, otherthan machinery spaces.

302 Unless expressly provided otherwise, a corridor, lobby,or part of a corridor from which there is only one route of es-cape shall be prohibited. Dead-end corridors used in service ar-eas which are necessary for the practical utility of the ship,such as fuel oil stations and athwartship supply corridors, shallbe permitted, provided such dead-end corridors are separatedfrom crew accommodation areas and are inaccessible frompassenger accommodation areas. Also, a part of a corridor thathas a depth not exceeding its width is considered a recess or lo-cal extension and is permitted.

303 All stairways in accommodation and service spaces andcontrol stations shall be of steel frame construction exceptwhere the Society sanctions the use of other equivalent mate-rial.

304 If a radiotelegraph station has no direct access to theopen deck, two means of escape from or access to, the stationshall be provided, one of which may be a porthole or windowof sufficient size or other means to the satisfaction of the Soci-ety.

305 Doors in escape routes shall, in general, open in way ofthe direction of escape, except that:

.1 individual cabin doors may open into the cabins in orderto avoid injury to persons in the corridor when the door isopened; and

.2 doors in vertical emergency escape trunks may open outof the trunk in order to permit the trunk to be used both forescape and for access.

306 At all levels of accommodation there shall be providedat least two widely separated means of escape from each re-stricted space or group of spaces.

307 Below the lowest open deck the main means of escapeshall be a stairway and the second escape may be a trunk or astairway.

308 Above the lowest open deck the means of escape shall bestairways or doors to an open deck or a combination thereof.

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309 No dead-end corridors having a length of more than 7 mshall be accepted.

310 The width, number and continuity of escape routes shallbe in accordance with the requirements in the Fire Safety Sys-tems Code.

311 Exceptionally the Administration may dispense withone of the means of escape, for crew spaces that are enteredonly occasionally, if the required escape route is independentof watertight doors.

F 400 Means of escape from machinery spaces


401 Except as provided in 402, two means of escape shall beprovided from each machinery space of category A. In partic-ular, one of the following provisions shall be complied with:

.1 two sets of steel ladders as widely separated as possibleleading to doors in the upper part of the space similarlyseparated and from which access is provided to the opendeck. One of these ladders shall be located within a pro-tected enclosure from the lower part of the space it servesto a safe position outside the space. Self-closing fire doorsof the same fire integrity standards shall be fitted in the en-closure. The ladder shall be fixed in such a way that heatis not transferred into the enclosure through non-insulatedfixing points. The enclosure shall have minimum internaldimensions of at least 800 mm x 800 mm, and shall haveemergency lighting provisions; or

.2 one steel ladder leading to a door in the upper part of thespace from which access is provided to the open deck and,additionally, in the lower part of the space and in a posi-tion well separated from the ladder referred to, a steel doorcapable of being operated from each side and which pro-vides access to a safe escape route from the lower part ofthe space to the open deck.

402 In a ship of less than 1 000 gross tonnage, the Societymay dispense with one of the means of escape required in 401,due regard being paid to the dimension and disposition of theupper part of the space. In addition, the means of escape frommachinery spaces of category A need not comply with the re-quirement for an enclosed fire shelter. In the steering gearspace, a second means of escape shall be provided when theemergency steering position is located in that space unlessthere is direct access to the open deck.

403 From machinery spaces other than those of category A,two escape routes shall be provided except that a single escaperoute may be accepted for spaces that are entered only occa-sionally, and for spaces where the maximum travel distance tothe door is 5 m or less.

F 500 Means of escape from ro-ro spaces


501 At least two means of escape are to be provided in ro-rospaces where the crew are normally employed. The escaperoutes are to provide a safe escape to the lifeboat and liferaftembarkation decks and are to be located at the fore and aft endsof the space.

G. Fire Control Plans

G 100 Fire Control Plans


101 General arrangement plans shall be permanently exhib-ited for the guidance of the ship’s officers, showing clearly foreach deck the control stations, the various fire sections en-closed by "A" class divisions, the sections enclosed by "B"class divisions together with particulars of the fire detection

and fire alarm systems, the sprinkler installation, the fire-extin-guishing appliances, means of access to different compart-ments, decks, etc., and the ventilating system includingparticulars of the fan control positions, the position of dampersand identification numbers of the ventilating fans serving eachsection. Alternatively, at the discretion of the Society, theaforementioned details may be set out in a booklet, a copy ofwhich shall be supplied to each officer, and one copy shall atall times be available on board in an accessible position. Plansand booklets shall be kept up to date; any alterations theretoshall be recorded as soon as practicable. Description in suchplans and booklets shall be in the language or languages re-quired by the Society. If the language is neither English norFrench, a translation into one of those languages shall be in-cluded.

102 A duplicate set of fire control plans or a booklet contain-ing such plans shall be permanently stored in a prominentlymarked weathertight enclosure outside the deckhouse for theassistance of shore-side fire-fighting personnel.

Guidance note:Refer to “Graphical symbols for fire control plans” adopted byIMO by Res. A.654(16) or to ISO 17631:2002 “Shipboard plansfor fire protection, life-saving appliances and means of escape”.


H. Fire Safety Measures for Cargo Ships less than 500 Gross Tonnage

H 100 Application101 The requirements in this section apply to cargo ships be-low 500 gross tonnage assigned main class.

H 200 Documentation201 The following plans and particulars are to be submittedfor approval:

— arrangement of means of escape including stairways, es-cape trunks, escape ladders, primary and secondary es-capes, assembly/muster stations and embarkation areas

— fire control plan— fire pumps and fire main including number and positions

of hydrants and hoses,— capacity calculation for fire pumps— fixed fire extinguishing arrangements in machinery spaces

if fitted. Specification and location of equipment and cal-culation of discharge capacities, if required.

H 300 Fire pumps301 Cargo ships above 150 but below 500 gross tonnage areto be provided with at least one independent driven fire pump.

302 Cargo ships of less than 150 gross tonnage are to have atleast one fire pump which may be driven by the main engine.

303 The main fire pumps referred to in 301 and 302 are tohave capacities not less than four-thirds of the quantity re-quired in Pt.4 Ch.6 Sec.4 H to be dealt with by each of the in-dependent bilge pumps in a passenger ship of the samedimension when employed in bilge pumping.

304 In every such ship provided with machinery space ofcategory A there is to be provided in a position outside thisspace a power or hand operated pump in addition to the pumpsrequired in 301 and 302. The pump is to have sufficient capac-ity and pressure to provide a 6 m jet throw with nozzles not lessthan 10 mm diameter. The jet throw is to be capable of beingdirected on to any part of the ship.

305 In cargo ships of less than 50 gross tonnage the pumpsreferred to above may be substituted by other approved equip-ment.

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H 400 Water distribution system401 Every such ship is to have fire hydrants of sufficientnumbers and so located that at least one powerful jet of watercan reach any part of the vessel accessible to persons on board.At least one hydrant to be provided in machinery space.

402 The fire main is to have a diameter of sufficient size tomaintain a steady distribution and pressure.

403 Materials used for the fire main are to be steel or equiv-alent material.

404 Pipe wall thicknesses are to be in accordance with Pt.4Ch.6 Sec.6 and material quality to be in accordance with Pt.4Ch.6 Sec.2.

405 Such ships are to be provided with one fire hose com-plete with coupling and nozzle for each 30 m of the ship, but inno case less than three in all. The hose length is not to exceed15 m.

406 The nozzles are to be of an approved dual purpose type(spray/jet) with 12 mm diameter and an integrated shut-offvalve. Other diameters may be considered.

407 For smaller vessels the water distribution system may besubstituted by other approved equipment.

H 500 Portable fire extinguishers501 Every such ship is to be provided with at least three ap-proved portable fire extinguishers so situated as to be readily

available for use in the accommodation and service spaces.

502 In each boiler room and in each space which containsany part of any oil fuel installation there is to be provided atleast two approved portable fire extinguishers suitable for ex-tinguishing oil fires.

503 In each machinery space of category A containing inter-nal combustion type machinery there is to be provided one ap-proved foam or powder type extinguisher suitable for oil firesfor each 750 kW or part thereof of such machinery. Not lessthan two such extinguishers are to be provided.

504 Smaller ships will be subjected to special consideration.

H 600 Non-portable fire extinguishers601 In cargo ships above 150 but below 500 gross tonnagefor unrestricted service there is to be provided in machineryspaces of category A one approved foam type extinguisher ofat least 45 litre capacity or equivalent. CO2 extinguisher of atleast 16 kg is considered equivalent.

Alternatively, a fixed fire extinguishing system may be provid-ed for machinery spaces of category A, in lieu of the foam typeextinguisher.

H 700 Fire-fighter's outfit701 Cargo ships of above 150 but below 500 gross tonnagefor unrestricted service are to be provided with at least two setsof fire-fighter's outfits.

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SECTION 11LIFESAVING ARRANGEMENT

A. Classification

A 100 Application

101 The rules in this chapter apply to vessels above 500gross tonnage.

Relevant additional requirements for passenger ships are givenin Pt.5 Ch.2 Sec.2.

102 The requirements in this chapter are in compliance withthe International Convention for the Safety of Life at Sea (SO-LAS) Chapter III with the latest amendments as per 1 January2003.

B. Documentation

B 100 Plans and particulars

101 The following drawing(s) shall be submitted for approv-al:

— Plan view and cross sections showing the:

— arrangement and launching of the survival craft, res-cue boat(s), Marine Evacuation System (MES) andMeans of Rescue) MOR at required combinations oflist and trim

— location of muster stations.

102 The following drawing shall be submitted for informa-tion:

— Safety Plan*

Guidance note:Guidance note:Reference is also given to the Recommendation on Testing ofLife-Saving Appliances adopted by IMO by resolutionMSC.81(70), and the Code of Practice for the Evaluation, Test-ing and Acceptance of Prototype Novel Life-Saving Appliancesand Arrangements adopted by IMO by resolution A.520(13).


* Safety Plan may be combined with Fire Control Plan.LSA symbols to be in accordance with IMO Res.A.760(18) as amended, showing the position and quantityof all life-saving appliances on board.

C. Survival Craft Muster and Embarkation Arrangements

C 100 (SOLAS Regulation III/11)

101

1 Lifeboats and liferafts for which approved launching ap-pliances are required shall be stowed as close to accom-modation and service spaces as possible.

2 Muster stations shall be provided close to the embarkationstations. Each muster station shall have sufficient cleardeck space to accommodate all persons assigned to musterat that station, but at least 0.35 m2 per person.

3 Muster and embarkation stations shall be readily accessi-ble from accommodation and work areas.

4 Muster and embarkation stations shall be adequately illu-minated by lighting supplied from the emergency sourceof electrical power required by Pt.5 Ch.2 Sec.2 D or Pt.4Ch.8 Sec.3 C, as appropriate.

5 Alleyways, stairways and exits giving access to the musterand embarkation stations shall be lighted. Such lightingshall be capable of being supplied by the emergencysource of electrical power required by Pt.5 Ch.2 Sec.2 Dor Pt.4 Ch.8 Sec.3 C, as appropriate. In addition to and aspart of the markings required under Pt.5 Ch.2 Sec.2 D orPt.5 Ch.2 Sec.2 E901, routes to muster stations shall be in-dicated with the muster station symbol, intended for thatpurpose, in accordance with IMO Resolutions A.760(18)and A.752(18).

6 Davit-launched and free-fall launched survival craft mus-ter and embarkation stations shall be so arranged as to en-able stretcher cases to be placed in survival craft.

7 An embarkation ladder complying with the requirementsof paragraph 6.1.6 of the International Lifesaving Appli-ances (LSA) Code extending, in a single length, from thedeck to the waterline in the lightest seagoing condition un-der unfavourable conditions of trim of up to 10° and a listof up to 20° either way shall be provided at each embarka-tion station or at every two adjacent embarkation stationsfor survival craft launched down the side of the ship.However, the Society may permit such ladders to be re-placed by approved devices to afford access to the surviv-al craft when waterborne, provided that there shall be atleast one embarkation ladder on each side of the ship. Oth-er means of embarkation enabling descent to the water ina controlled manner may be permitted for the liferafts re-quired by regulation 31.1.4 (see J100).

8 Where necessary, means shall be provided for bringingthe davit-launched survival craft against the ship's sideand holding them alongside so that persons can be safelyembarked.

D. Launching Stations

D 100 (SOLAS Reg. III/12)101 Launching stations shall be in such positions as to ensuresafe launching having particular regard to clearance from thepropeller and steeply overhanging portions of the hull and sothat, as far as possible, survival craft, except survival craft spe-cially designed for free-fall launching, can be launched downthe straight side of the ship. If positioned forward, they shall belocated abaft the collision bulkhead in a sheltered position and,in this respect, the Society shall give special consideration tothe strength of the launching appliance.

The strength of launching appliance is to be based on relevantloads as given in Pt.3 Ch.1 Sec.4.

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E. Stowage of Survival Craft

E 100 (SOLAS Reg. III/13)

101

1 Each survival craft shall be stowed:

2 Lifeboats for lowering down the ship's side shall bestowed as far forward of the propeller as practicable. Oncargo ships of 80 m in length and upwards but less than120 m in length, each lifeboat shall be so stowed that theafter end of the lifeboat is not less than the length of thelifeboat forward of the propeller. On cargo ships of 120 min length and upwards and passenger ships of 80 m inlength and upwards, each lifeboat shall be so stowed thatthe after end of the lifeboat is not less than 1.5 times thelength of the lifeboat forward of the propeller. Where ap-propriate, the ship shall be so arranged that lifeboats, intheir stowed positions, are protected from damage byheavy seas.

3 Lifeboats shall be stowed attached to launching applianc-es.

4.1 Every liferaft shall be stowed with its painter permanentlyattached to the ship.

4.2 Each liferaft or group of liferafts shall be stowed with afloat-free arrangement complying with the requirementsof paragraph 4.1.6 of the LSA Code so that each floats freeand, if inflatable, inflates automatically when the shipsinks.

4.3 Liferafts shall be so stowed as to permit manual release ofone raft or container at a time from their securing arrange-ments.

4.4 Paragraphs 4.1 and 4.2 do not apply to liferafts requiredby regulation 31.1.4 (see J100).

5 Davit-launched liferafts shall be stowed within reach ofthe lifting hooks, unless some means of transfer is provid-ed which is not rendered inoperable within the limits oftrim and list prescribed in paragraph 1.2 or by ship motionor power failure.

6 Liferafts intended for throw-overboard launching shall beso stowed as to be readily transferable for launching on ei-ther side of the ship unless liferafts, of the aggregate ca-pacity required by regulation 31.1 (see J100) to be capable

of being launched on either side, are stowed on each sideof the ship.

F. Stowage of Rescue Boats

F 100 (SOLAS Reg. III/14)

101 Rescue boats shall be stowed:

1 in a state of continuous readiness for launching in notmore than 5 min;

2 in a position suitable for launching and recovery;3 so that neither the rescue boat nor its stowage arrange-

ments will interfere with the operation of any survivalcraft at any other launching station; and

4 if it is also a lifeboat, in compliance with the requirementsof regulation 13 (see E100).

G. Stowage of Marine Evacuation Systems

G 100 (SOLAS Reg. III/15)

101

1 The ship's side shall not have any openings between theembarkation station of the marine evacuation system andthe waterline in the lightest seagoing condition and meansshall be provided to protect the system from any projec-tions.

2 Marine evacuation systems shall be in such positions as toensure safe launching having particular regard to clear-ance from the propeller and steeply overhanging positionsof the hull and so that, as far as practicable, the system canbe launched down the straight side of the ship.

3 Each marine evacuation system shall be stowed so thatneither the passage nor platform nor its stowage or opera-tional arrangements will interfere with the operation ofany other life-saving appliance at any other launching sta-tion.

4 Where appropriate, the ship shall be so arranged that themarine evacuation systems in their stowed positions areprotected from damage by heavy seas.

H. Survival Craft Launching and Recovery Arrangements

H 100 (SOLAS Reg. III/16)

101

1 Unless expressly provided otherwise, launching and em-barkation appliances complying with the requirements ofsection 6.1 of the Code shall be provided for all survivalcraft except those which are:.

.1 so that neither the survival craft nor its stowage ar-rangements will interfere with the operation of any other survival craft or rescue boat at any other launching station;

.2 as near the water surface as is safe and practicable and, in the case of a survival craft other than a lifer-aft intended for throw over board launching, in such a position that the survival craft in the embarkation position is not less than 2 m above the waterline with the ship in the fully loaded condition under un-favourable conditions of trim of up to 10° and listed up to 20°either way, or to the angle at which the ship's weather deck edge becomes submerged, whichever is less;

.3 in a state of continuous readiness so that two crew members can carry out preparations for embarka-tion and launching in less than 5 min;

.4 fully equipped as required by this chapter and the Code; and

.5 as far as practicable, in a secure and sheltered posi-tion and protected from damage by fire and explo-sion. In particular, survival craft on tankers, other than the liferafts required by regulation 31.1.4 (see J100), shall not be stowed on or above a cargo tank, slop tank, or other tank containing explosive or haz-ardous cargoes.

.1 boarded from a position on deck less than 4.5 m above the waterline in the lightest seagoing condi-tion and which have a mass of not more than 185 kg; or.

.2 boarded from a position on deck less than 4.5 m above the waterline in the lightest seagoing condi-tion and which are stowed for launching directly from the stowed position under unfavourable con-ditions of trim of up to 10° and list of up to 20° ei-ther way; or.

.3 carried in excess of the survival craft for 200% of the total number of persons on board the ship and which have a mass of not more than 185 kg; or.

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2 Each lifeboat shall be provided with an appliance which iscapable of launching and recovering the lifeboat. In addi-tion there shall be provision for hanging-off the lifeboat tofree the release gear for maintenance.

3 Launching and recovery arrangements shall be such thatthe appliance operator on the ship is able to observe thesurvival craft at all times during launching and for life-boats during recovery.

4 Only one type of release mechanism shall be used for sim-ilar survival craft carried on board the ship.

5 Preparation and handling of survival craft at any onelaunching station shall not interfere with the prompt prep-aration and handling of any other survival craft or rescueboat at any other station.

6 Falls, where used, shall be long enough for the survivalcraft to reach the water with the ship in its lightest seago-ing condition, under unfavourable conditions of trim of upto 10° and list of up to 20° either way.

7 During preparation and launching, the survival craft, itslaunching appliance, and the area of water into which it isto be launched shall be adequately illuminated by lightingsupplied from the emergency source of electrical powerrequired by regulation II-1/42 or II-1/43 (Pt.5 Ch.2 Sec.2D or Pt.4 Ch.8 Sec.2 C, respectively), as appropriate.

8 Means shall be available to prevent any discharge of wateron to survival craft during abandonment.

9 If there is a danger of the survival craft being damaged bythe ship's stabilizer wings, means shall be available, pow-ered by an emergency source of energy, to bring the stabi-lizer wings inboard; indicators operated by an emergencysource of energy shall be available on the navigatingbridge to show the position of the stabilizer wings.

10 If partially enclosed lifeboats complying with the require-ments of section 4.5 of the Code are carried, a davit spanshall be provided, fitted with not less than two lifelines ofsufficient length to reach the water with the ship in itslightest seagoing condition, under unfavourable condi-tions of trim of up to 10° and list of up 20° either way.

I. Rescue Boat Embarkation, Launching and Recovery Arrangement

I 100 (SOLAS Reg. III/17)

101

1 The rescue boat embarkation and launching arrangementsshall be such that the rescue boat can be boarded andlaunched in the shortest possible time.

2 If the rescue boat is one of the ship's survival craft, the em-barkation arrangements and launching station shall com-ply with the requirements of regulations 11 (see G100)and 12 (see D100).

3 Launching arrangements shall comply with the require-ments of regulation 16 (see H100). However, all rescueboats shall be capable of being launched, where necessaryutilizing painters, with the ship making headway at speedsup to 5 knots in calm water.

4 Recovery time of the rescue boat shall be not more than 5min in moderate sea conditions when loaded with its fullcomplement of persons and equipment. If the rescue boatis also a lifeboat, this recovery time shall be possible whenloaded with its lifeboat equipment and the approved res-cue boat complement of at least six persons.

5 Rescue boat embarkation and recovery arrangements shallallow for safe and efficient handling of a stretcher case.Foul weather recovery strops shall be provided for safetyif heavy fall blocks constitute a danger.

J. Survival Craft and Rescue Boats

J 100 (SOLAS Reg. III/31)101

1 Survival craft

.4 carried in excess of the survival craft for 200% of the total number of persons on board the ship, are stowed for launching directly from the stowed posi-tion under unfavourable conditions of trim of up to 10° and list of up to 20° either way, or.

.5 provided for use in conjunction with a marine evac-uation system, complying with the requirements of section 6.2 of the Code and stowed for launching di-rectly from the stowed position under unfavourable conditions of trim of up to 10° and list of up to 20° either way.

1.1 Cargo ships shall carry:.1 one or more totally enclosed lifeboats complying

with the requirements of section 4.6 of the Code of such aggregate capacity on each side of the ship as will accommodate the total number of persons on board; and

.2 in addition, one or more inflatable or rigid lifer-afts, complying with the requirements of section 4.2 or 4.3 of the Code, stowed in a position pro-viding for easy side-to-side transfer at a single open deck level, and of such aggregate capacity as will accommodate the total number of persons on board. If the liferaft or liferafts are not stowed in a position providing for easy side-to-side transfer at a single open deck level, the total ca-pacity available on each side shall be sufficient to accommodate the total number of persons on board.

1.2 In lieu of meeting the requirements of paragraph 1.1, cargo ships may carry:.1 one or more free-fall lifeboats, complying with

the requirements of section 4.7 of the Code, ca-pable of being free-fall launched over the stern of the ship of such aggregate capacity as will ac-commodate the total number of persons on board; and

.2 in addition, one or more inflatable or rigid lifer-afts complying with the requirements of section 4.2 or 4.3 of the Code, on each side of the ship, of such aggregate capacity as will accommodate the total number of persons on board. The lifer-afts on at least one side of the ship shall be served by launching appliances.

1.3 In lieu of meeting the requirements of paragraph 1.1 or 1.2, cargo ships of less than 85 m in length other than oil tankers, chemical tankers and gas carriers, may comply with the following:.1 they shall carry on each side of the ship, one or

more inflatable or rigid liferafts complying with the requirements of section 4.2 or 4.3 of the Code and of such aggregate capacity as will accommo-date the total number of persons on board.

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2 Rescue boats

Cargo ships shall carry at least one rescue boat complyingwith the requirements of section 5.1 of the Code. A life-boat may be accepted as a rescue boat, provided that italso complies with the requirements for a rescue boat.

In order to approve a totally enclosed lifeboat as a rescueboat, the totally enclosed lifeboat must have featureswhich enables it to meet all of the requirements of a rescueboat including the retrieval requirements specified in reg-ulations 17.4 (see I100) and 6.1.1.9 of the LSA Code.

(MSC/Circ.508)

K. Survival Craft Embarkation and Launching Arrangements

K 100 (SOLAS Reg. III/33)101

1 Cargo ship survival craft embarkation arrangements shallbe so designed that lifeboats can be boarded and launcheddirectly from the stowed position and davit-launched lif-erafts can be boarded and launched from a position imme-diately adjacent to the stowed position or from a positionto which the liferaft is transferred prior to launching incompliance with the requirements of regulation 13.5 (seeE100).

2 On cargo ships of 20 000 gross tonnage and upwards, life-boats shall be capable of being launched, where necessaryutilizing painters, with the ship making headway at speedsup to 5 knots in calm water.

.2 unless the liferafts required by paragraph 1.3.1 are stowed in a position providing for easy side-to-side transfer at a single open deck level, addi-tional liferafts shall be provided so that the total capacity available on each side will accommo-date 150% of the total number of persons on board;.3 if the rescue boat required by paragraph 2 is also a totally enclosed lifeboat complying with the requirements of section 4.6 of the Code, it may be included in the aggregate capacity re-quired by paragraph 1.3.1, provided that the total capacity available on either side of the ship is at least 150% of the total number of persons on board; and.4 in the event of any one survival craft being lost or rendered unserviceable, there shall be sufficient survival craft available for use on each side, including any which are stowed in a position providing for easy side-to-side transfer at a single open deck level, to accommodate the total number of persons on board.

1.4 Cargo ships where the horizontal distance from the extreme end of the stem or stern of the ship to the nearest end of the closest survival craft is more than 100 m shall carry, in addition to the liferafts required by paragraphs 1.1.2 and 1.2.2, a liferaft stowed as far forward or aft, or one as far forward and another as far aft, as is reasonable and practicable. Such liferaft or liferafts may be securely fastened so as to permit manual release and need not be of the type which can be launched from an approved launching device.

1.5 With the exception of the survival craft referred to in regulation 16.1.1 (see H100), all survival craft re-quired to provide for abandonment by the total number of persons on board shall be capable of being launched with their full complement of persons and equipment within a period of 10 min from the time the abandon ship signal is given.

1.6 Chemical tankers and gas carriers carrying cargoes emitting toxic vapours or gases* shall carry, in lieu of totally enclosed lifeboats complying with the require-ments of section 4.6 of the Code, lifeboats with a self-contained air support system complying with the re-quirements of section 4.8 of the Code.

1.7 Oil tankers, chemical tankers and gas carriers carry-ing cargoes having a flashpoint not exceeding 60°C (closed cup test) shall carry, in lieu of totally enclosed lifeboats complying with the requirements of section 4.6 of the Code, fire-protected lifeboats complying with the requirements of section 4.9 of the Code.

* Refer to products for which emergency escape respi-ratory protection is required in chapter 17 of the In-ternational Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (IBC Code), adopted by the Maritime Safety Com-mittee by resolution MSC.4(48) and in chapter 19 of the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code), adopted by the Maritime Safety Committee by resolution MSC.5(48).

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SECTION 12INTERNAL COMMUNICATION

A. General Requirements

A 100 Application

101 This section contains all requirements pertaining to pub-lic address systems, systems for two-way voice communica-tion, and general alarm systems including relevant SOLASregulations with the latest amendments.

102 If any part of this section contains requirements whichappear to be inconsistent with SOLAS, then the interpretationbased on SOLAS takes precedence.

103 The requirements of B applies to all ships for the assign-ment of main class. Reference to similar SOLAS requirementsis given after each item.

104 The requirements of C apply to ships for the assignmentof service notations and additional class notations.

A 200 Classification

201 Classification of the intercom systems consists of thefollowing main elements:

— approval of design documentation— approval test of application software (ATOS) if computer

and ATOS are requested— certification if computer based and if requested— onboard survey and testing.

A 300 Design documentation

301 Plans, particulars and or system descriptions are to besubmitted with the objective of:

— ensuring that requirements concerning intercom systemshas been addressed during the design of the ship

— ensuring that all applicable requirements will be compliedwith when the ship has been completed, without requiringmajor changes and/or additions to the systems at a finalstage.

— ensuring reliability through verification of technical andenvironmental specifications.

302 The documentation is to contain the information neces-sary to verify compliance with the requirements in this sectionand with environmental parameters as described in Pt.4 Ch.9Sec.5 B. Generally the documentation should be kept as briefas possible, and may be divided in the following main ele-ments:

1) Functional requirements (general alarm and public ad-dress systems shall comply with IMO A.830 (19)).

2) Location requirements.

3) Power supply requirements and cabling.

4) Environmental requirements.

Guidance note:Item 1 may be covered by a short description of the system(s).

Item 2 may be covered by tables/descriptions giving the neces-sary information regarding locations of components, types, pow-er outputs, dB levels etc. Alternatively, drawings showing thephysical location of components may be submitted.

Item 3 may be covered with a short description or a one-line gen-eral arrangement drawing.

Item 4 (and 1) will be considered as complied with if the systemis type approved. If the system(s) are not type approved, a case

by case approval may be carried out based on submitted docu-mentation, data sheets/instruction books, or equivalent.


303 In addition to documentation approved by the Society,manuals and drawings providing operational and technical in-formation for service and maintenance purposes are to be de-livered on board.

A 400 ATOS or certification at the manufacturer401 Before installation, the systems are to be tested in orderto ensure compliance with the rules, in regard to functionality.Comments made in connection with approval of the documen-tation are to be clarified.

A 500 Onboard survey or functional testing501 When completed, the systems are to be tested in order toensure compliance with the rules in regard to functionality.Furthermore, it is to be verified that the approved documenta-tion is consistent with the final installation.

502 Final approval of the systems takes place following thesurvey, when comments and recommendations, if any, havebeen complied with.

A 600 Terms, definitions and abbreviations601 The terms intercom and internal communications, whenused generally, apply to the following:

— public address systems— general alarm systems— two-way voice communication systems such as

— telephone systems— talk back systems.

602 Where the Code is referred to in the text, this means theInternational Life-Saving Appliance (LSA) Code adopted byIMO by res. MSC.48(66).

B. Ship Requirements - Main Class

B 100 Two way voice communication101 A means of communication shall be provided betweenthe navigation bridge and the steering gear compartment.

(Regulation II-1/29.10)

102 At least two independent means shall be provided forcommunicating orders from the navigation bridge to the posi-tion in the machinery space or in the control room from whichthe speed and direction of thrust of the propellers are normallycontrolled; one of these shall be an engine-room telegraphwhich provides visual indication of the orders and responsesboth in the machinery spaces and on the navigation bridge.


103 Appropriate means of communication shall be providedfrom the navigation bridge and the engine-room to any otherposition from which the speed or direction of thrust of the pro-pellers may be controlled.


104 An emergency means comprised of either fixed or port-able equipment or both shall be provided for two-way commu-nications between emergency control stations, muster andembarkation stations and strategic positions on board.

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(Regulation III/6.4.1)Guidance note:Strategic positions are the bridge and engine control room.


105 Ships of 150 gross tonnage and upwards shall be fittedwith adequate means of communication between the standardcompass position and the normal navigation control position tothe satisfaction of the Administration.

(Regulation V/12(b))Guidance note:This provision is considered as complied with if portable VHF/UHFs are available on board.


106 Ships with emergency steering positions shall at least beprovided with a telephone or other means of communicationfor relaying heading information to such positions.

(Regulation V/12(f))

B 200 Public address system/General alarm

201 A general emergency alarm system complying with therequirements of paragraph 7.2.1. of the Code shall be providedand shall be used for summoning the passengers and crew tomuster stations and to initiate the actions included in the mus-ter list. The system shall be supplemented by either a public ad-dress system complying with the requirements of paragraph7.2.2 of the Code or other suitable means of communication.Entertainment sound systems shall automatically be turned offwhen the general emergency alarm system is activated.

(Regulation III/6.4.2)Guidance note:For cargo ships, alternatives to a public address system may beaccepted, provided that the alternative system provides an equiv-alent safety level.


202 On passenger ships the general emergency alarm systemshall be audible on all open decks.

(Regulation III/6.4.3)

203 On ships fitted with a marine evacuation system com-munication between the embarkation station and the platformor the survival craft shall be ensured.


204 Public address systems on passenger ships

In addition to the requirements of regulation II-2/40.5 or regu-lation II-2/41-2, as appropriate, and of paragraph III/6.4.2, allpassenger ships shall be fitted with a public address system.


205 The public address system shall be clearly audible abovethe ambient noise in all spaces, prescribed by paragraph 7.2.2.1of the Code, and shall be provided with an override functioncontrolled from one location on the navigation bridge and suchother places on board as the Administration deems necessary,so that all emergency messages will be broadcast if any loud-speaker in the spaces concerned has been switched off, its vol-ume has been turned down or the public address system is usedfor other purposes.


206 On passenger ships constructed on or after 1 July 1997:

1 the public address system shall have at least two loops whichshall be sufficiently separated throughout their length and havetwo separate and independent amplifiers; and

2 the public address system and its performance standards shall

be approved by the Administration having regard to the recom-mendations adopted by the Organisation. *

* Refer to performance standards for public address sys-tems contained in MSC/Circ.808.

(Regulation III/6.5.3)Guidance note:The effect of one failure should be minimised as far as possible.All areas of each fire zone should be served by two loops andsupplied by independent amplifiers so that announcements in allareas are audible in the case of failure of one loop or amplifier.Amplifiers should be physically separated, and if only two am-plifiers are used for the complete system, they should not be lo-cated in the same fire zone.


207 The public address system shall be connected to theemergency source of electrical power required by regulationII-1/42.2.2 (Pt.5 Ch.2 Sec.2 D204).


208 Ships constructed before 1 July 1997 which are alreadyfitted with the public address system approved by the Admin-istration which complies substantially with those required bysections 5.2 (205) and 5.4 (207) and paragraph 7.2.2.1 of theCode are not required to change their system.


B 300 Electrical requirements

301 The emergency source of electrical power shall operateall internal communication equipment as required in an emer-gency for a period of minimum 18 hours (cargo ships).

Guidance note:The above requirement does not prevent the use of self-containedcommunication systems, such as sound powered telephones orother battery operated communication systems, provided the ca-pacity of the energy source is sufficient to operate the system for18 hours (cargo ships).


302 Conductors are to have a minimum cross section of 0.5mm2 for communication cables and 1.5 mm2 for power cables.

303 Cables should be routed clear of galleys, machineryspaces and their casings and other high fire risk areas, exceptfor supplying equipment in those spaces.

304 Communication cables are to be earthed at one end only.

305 Communication equipment located or used in areaswhere flammable gases may be present are to be certified in-trinsically safe.

C. Ship Requirements - Additional Class

C 100 Fishing vessels

101 If the 'tween-deck is fitted with side openings, a meansof communication between the bridge and the doors in the ves-sel's side and stern is to be provided. If this is not the case, thenTV monitoring is to be provided.

C 200 Oil production and storage vessels

201 A two-way voice communication system is to be provid-ed, making it possible to call all areas likely to be regularlymanned from the control stations, navigation bridge and en-gine room(s).

Guidance note:Control stations are those spaces in which the radio, main navi-gating equipment, central fire detection or control systems, gasdetection system, central internal communication equipment,

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emergency shut-down system, or emergency source of power arelocated.


202 At least four simultaneous voice connections are to bepossible giving priority to the control stations and the naviga-tion bridge.

203 The required intercom systems are to be capable of be-ing supplied from the emergency source of power, for a periodof at least 24 hours.

204 A monitored UPS is to be provided for all safety sys-tems, including communication and general alarm systems.

C 300 Periodically unattended machinery space301 For ships above 500 gross tonnage a reliable means ofvocal communication shall be provided between the main ma-chinery control room or the propulsion machinery control po-sition as appropriate, the navigation bridge and engineerofficers' accommodation.

(Regulation II-1/50)

302 At least 4 simultaneous voice connections are to be pos-sible, alternatively the connection between the bridge and theengine rooms is to have priority above other connections.

303 The means of vocal communication is to function duringblack-out.

C 400 Dynamic positioning systems401 A two-way voice communication facility is to be provid-ed between the DP-system control centre and the navigationbridge, ECR and relevant operation control centres.

402 The internal communication system is to operate inde-pendently of the vessel's main power system.

C 500 Nautical safety501 Batteryless telephone systems

To secure internal communications independent of an electri-cal power supply, a batteryless telephone system shall be pro-vided for two-way communication between the wheelhouseand the:

— engine control room— steering gear room— captain's living quarters— chief engineer's living quarters— radio room (when located outside of the bridge area).

In the steering gear room, facilities shall be provided to avoidnoise interference when using the batteryless telephone.

502 Automatic telephone systems

The automatic telephone network is to provide two-way com-munication between the bridge, all workstations and all rele-vant spaces, and is to function during black-out. Thewheelhouse is to be fitted with 2 independent user extensions.Incoming calls on adjacent telephones are to be distinguishableby lights and/or different ring tones. The telephone network is

to be designed with a minimum capacity for 2 simultaneouscalls. The telephones in the wheelhouse and engine controlroom are to have priority function over any other extension.

A reference list of extensions is to be permanently posted with-in reach of each telephone.

503 Public address systems

The public address (PA) system is to enable point-to-pointloud hailing intercom between the bridge and all relevant are-as, and is to function during black-out.

The PA control module is to be suitable for flush panel mount-ing in workstation consoles. Outdoor substations shall bemounted in a watertight housings.

Each substation is to be equipped with an activation light to in-dicate communication readiness. The talk-back speaker sys-tems are to have a volume control.

The amplifier units are to be protected against failure in the in-tercom network or in the substation equipment.

Guidance note:

a) The PA control module, including microphone and talk-back devices, is to be located in the wheelhouse.

b) The following areas are recommended to be fitted with a PAtalk-back substation:

- bridge wings- forecastle deck- aft mooring station- midship mooring station- steering gear room- engine control room- cargo control room- cabins (speaker only)- offices and lounges (speaker only)


504 UHF System

To assist in safety and navigation, the bridge is to be providedwith at least 4 portable UHF transceivers operating in the 457to 467 MHz band.

The equipment is to include microphone, loudspeaker andchargeable batteries, with a capacity to operate the equipmentcontinuously for at least 5 hours.

Guidance note:Continuous operation means sequences of 1 minute transmis-sions followed by 9 minutes reception, without signals at the re-ceiver input.


505 A battery charger having sufficient capacity to re-chargeall UHF transceivers simultaneously shall be installed in aneasily accessible location within the wheelhouse.

Guidance note:The charger unit or units should as a minimum have slots for 4UHF transceivers and be capable of re-charging the 4 UHF trans-ceivers.


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Rules for Ships, January 2003 Pt.3 Ch.3 App.A –

APPENDIX AADDITIONAL REQUIREMENTS FOR NON — DUPLICATED RUDDER

ACTUATORS

A. Introduction

A 100 Scope101 The requirements given in this Appendix are in compli-ance with IMO «Guidelines» for the acceptance of non-dupli-cated rudder actuators for oil carriers, chemical carriers andliquefied gas carriers of 10 000 tons gross and upwards but ofless than 100 000 tonnes deadweight.

B. Materials

B 100 Special Requirements101 Parts subject to internal hydraulic pressure or transmit-ting mechanical forces to the rudder-stock are to be made ofduly tested ductile materials complying with recognised stand-ards. Materials for pressure retaining components are to be inaccordance with recognised pressure vessel standards. Thesematerials are not to have an elongation less than 12% nor a ten-sile strength in excess of 650 N/mm2.

C. Design

C 100 Design pressure101 The design pressure should be assumed to be at leastequal to the greater of the following:

— 1.25 times the maximum working pressure to be expectedunder the operating conditions required in Sec.2 J102.b)

— the relief valve(s) setting.

C 200 Analysis201 In order to analyse the design the following are required:

— The manufacturers of rudder actuators should submit de-tailed calculations showing the suitability of the design forthe intended service.

— A detailed stress analysis of the pressure retaining parts ofthe actuator should be carried out to determine the stressesat the design pressure.

— Where considered necessary because of the design com-plexity or manufacturing procedures, a fatigue analysisand fracture mechanics analysis may be required. In con-nection with these analyses, all foreseen dynamic loadsshould be taken into account. Experimental stress analysismay be required in addition to, or in lieu of, theoretical cal-culations depending upon the complexity of the design.

C 300 Dynamic loads for fatigue and fracture mechan-ics analysis301 The assumptions for dynamic loading for fatigue andfracture mechanics analyses where required in 200 and inSec.2 J205, J1102 are to be submitted for appraisal. Both thecase of high cycle and cumulative fatigue are to be considered.

C 400 Allowable stresses401 For the purpose of determining the general scantlings ofparts of rudder actuators subject to internal hydraulic pressurethe allowable stresses are not to exceed:

σm ≤ f

σ1 ≤ 1.5 f

σb ≤ 1.5 f

σ1 + σb ≤ 1.5 f

σm + σb ≤ 1.5 f

where

σm = equivalent primary general membrane stressσ1 = equivalent primary local membrane stressσb = equivalent primary bending stress

f = the lesser of

σ ts = specified minimum tensile strength of material at am-bient temperature

σf = specified minimum yield stress or 0.2% proof stress ofmaterial at ambient temperature.

A and B are as follows:

C 500 Burst test501 Pressure retaining parts not requiring fatigue analysisand fracture mechanics analysis may be accepted on the basisof a certified burst test and the detailed stress analysis requiredby 200 need not be provided.

The minimum bursting pressure is to be calculated as follows:

where

PB = minimum bursting pressureP = design pressure as defined in 100A = as from table in 400σ ta = actual tensile strengthσ ts = tensile strength as defined in 400.

D. Construction Details

D 100 General101 The construction should be such as to minimise localconcentrations of stress.

D 200 Welds201 The welding details and welding procedures should beapproved. All welded joints within the pressure boundary of arudder actuator or connection parts transmitting mechanicalloads should be full penetration type or of equivalent strength.

D 300 Oil seals301 Oil seals forming part of the external pressure boundaryare to comply with Sec.2 J209 and J210.

D 400 Isolating valvesIsolating valves are to be fitted at the connection of pipes to theactuator, and should be directly mounted on the actuator.

Table C1 Permissible primary membrane stressSteel Cast steel Nodular cast iron

AB

4 2

4.6 2.3

5.8 3.5

σts

A------- or

σf

B-----

PB PAσta

σts-------=

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Rules for Ships, January 2003Pt.3 Ch.3 App.A –

D 500 Relief valves501 Relief valves for protecting the rudder actuator againstoverpressure as required in Sec.2 J305 are to comply with thefollowing:

— The setting pressure is not to be less than 1.25 times themaximum working pressure expected under operatingconditions required by Sec.2 J102.b).

— The minimum discharge capacity of the relief valve(s) isto be not less than 110% of the total capacity of all pumpswhich provide power for the actuator. Under such condi-tions the rise in pressure should not exceed 10% of the set-ting pressure. In this regard due consideration should begiven to extreme foreseen ambient conditions in respect ofoil viscosity.

E. Testing

E 100 Non-destructive testing

101 The rudder actuator should be subjected to suitable andcomplete non-destructive testing to detect both surface flawsand volumetric flaws. The procedure and acceptance criteriafor non-destructive testing should be in accordance with re-quirements of recognised standards. If found necessary, frac-ture mechanics analysis may be used for determiningmaximum allowable flaw size.

E 200 Other testing

201 Tests, including hydrostatic tests, of all pressure parts at1.5 times the design pressure should be carried out.

202 When installed on board the ship, the rudder actuatorshould be subjected to a hydrostatic test and a running test.

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