Owners’ guide to CommonStructural Rules for Bulk carriers

DNV Maritime

DNV Maritime

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DNV offers state-of-the-art competence and services for bulk carriers

DNV has over the years accumulated unique bulk carrier competence. We are also scaling up our efforts to grow

within the bulk carrier segment. We are market leaders in the special bulkcarrier design such as open hatch

design, and a major part of the existing large ore carriers have been classified by DNV.

We have developed a wide range of additional class notations to suit owners’ different needs for safe and reliable

ship operations.

DNV welcomes the new IACS Common Structural Rules (CSR) for bulk carriers, and is prepared to offer our

dedicated services to the bulk carrier industry based on the new rules, supported by updated and preferred

software tools. The Nauticus Hull software made by DNV Software provides unique support for CSR, combined

with a highly efficient environment for ship design. Its capabilities range from simplified rule-check and scantling

calculations to advanced tools for extended calculation procedures, including wave load and finite element

structural analysis

DNV Software is the commercial software house of DNV serving more than 3,000 customers in the marine,

offshore and process industries. DNV Software is a market leader in software development for design, strength

assessment, risk and information management.

We will be pleased to discuss new projects and share our experience with designers, yards and owners thereby

contributing to a successful end result.

For continuously updated information on the new Common Structural Rules, please consult:

www.dnv.com/maritime and www.dnv.com/software

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The IACS CSR for Bulk carriersThe IACS Common Structural Rules (CSR) entered in to force 1st of April 2006.The new standard applies to all bulk carriers, single or double side, equal to orabove 90 meters in length.

DNV has expanded its activity world-wide to assistclients in implementing the CSR. An extensive train-ing program has been implemented for all approvalunits enabling our staff to be well prepared to pro-vide efficient and local support to the industry.

We are also very pleased to introduce this practicalguide to the new Rules. The guide is primarily writtenfor use by shipowners and shipmanaging companies,with main focus on practical implications, and less onthe detailed technical scope of the Rules.

We hope this may prove a useful tool in your imple-mentation of CSR. We are looking forward to workingactively with you and being your preferred partner fornew bulk carriers constructed/designed to the newCSR standard!

Tor E. Svensen, COO DNV Maritime

The Common Structural Rules (CSR) arethe result of the combined knowledge,experience and latest technical expertise ofthe world’s ten leading classification soci-eties, and they embody the very latest inpractical experience and state-of-the-arttechnological knowledge.

Implementation of the new Rules The new Rules are applied by all the IACSmember societies for bulk carriers withlength equal to or greater than 90 m con-tracted for construction after 1 April 2006.The CSR cover the ship hull only. For bulkcarriers below 90 m and for all other mat-ters such as machinery, electrical andautomation systems, etc. the existing classRules still apply.

DNV-classed bulk carriers built to theCommom Structural Rules (CSR) will be

given the class notation @1A1 Bulk CarrierESP CSR GRAB(X)…, with the additionalCSR notation replacing the existing NAU-

TICUS (Newbuilding) notation. Other nota-tions will not be affected, and hence addi-tional notations such as BC-A Holds 2,4,6

& 8 may be Empty, E0, TMON, BIS, NAUT,

BWE-E just to mention the most commonlyused, will still be available.

The existing NAUTICUS (Newbuilding)

notation is still available and will beapplied to non CSR vessels as before.

For clarification a brief description of

above DNV notations is given below:

@1A1: DNV’s main class notation for hulland machinery.Bulk Carrier ESP: Bulk Carrier is the shiptype and service notation. “ESP” meansEnhanced Survey Programme, which ismandatory for Bulk Carriers.BC-A Holds 2, 4, 6 and 8 may be empty:

Vessels with this notation is designed totake full cargo deadweight in alternateloading. I.e. with holds 2, 4, 6 and 8 empty. NAUTICUS(Newbuilding): This notationprovides additional extended fatigue- anddirect strength calculations.E0: Means the vessel is designed for unat-tended machinery space.TMON: With arrangement complyingwith this notation the Society will notrequire any specific time interval betweencomplete tailshaft surveys.DG-: This notation may be assigned forvessels designed for carriage of dangeroussolid bulk cargoes in accordance withSOLAS and the BC-Code.BIS: With arrangement complying with thisnotation the vessel may avoid dry dockingevery 2.5 years (intermediate survey). GRAB(X): This notation means that theinner bottom and lower part of the bulk-head stools and hopper is strengthenedfor grab loading. Minimum design weightof an unladen grab is 20t.NAUT-OC/AW: The Class Notations repre-

sent minimum requirements within bridgedesign, instrumentation and procedures.BWW-E ( ): Ballast water exchange wherea predefined letter in the bracket denotesthe method for exchange that has beenapplied.

Main characteristics of CSR The CSR were developed as a fine balancebetween new requirements, methods, cal-culation tools and existing empiricalrequirements developed and tested overseveral decades. The result is Rules updatedin accordance with new technology andknowledge but at the same time incorpo-rating the experience gained through theoperation and survey of existing vessels inservice. The new key features of the CSRare:n transparency in development and appli-

cationn new load model for strength calculationn net thickness approachn coatingn enhanced fatigue standardn buckling and hull girder ultimate limit

state assessment.

Transparency in the Rules is providedthrough clear objectives, clarification ofthe scope of the Rules, the Rules’ designbasis and, consequently, the Rules’ rangeof applicability and limitations.

The development of the new RulesThe development of the new Rules for Bulk carriers was initiated at the beginning of2004 with the objective of developing common Rules to prevent possible competitionbetween Classification Societies on the minimum safety standards. Valuable input wasgiven by industry during extensive hearing periods, leading to refinements of the Rulesand ultimately producing the Rules as they have now been published.

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The new load formulations which areapplied consistently throughout the Rulesfor prescriptive requirements, finite ele-ment analyses and fatigue have beendeveloped using 3D hydrodynamic analy-ses validated through model tests.

A net thickness philosophy has been adoptedfor the new Rules, providing a direct linkbetween the thickness used for strengthcalculations during the design stage andthe minimum steel thickness acceptedduring the ship’s operational life. Thestrength calculations performed duringthe design stage are based on net scant-lings. Newbuilding gross scantling require-ments are calculated by the addition of anallowance for the expected wastage duringthe design life of the vessel to therequired net scantlings determined inaccordance with the Rule requirements.

The corrosion margins specified in theCSR for different structural elementsreflect the different rates at which the dif-ferent areas of the ship corrode, sincelocal areas corrode at rates that can differwidely from the average corrosion rate ofthe whole ship. This is therefore a morerealistic approach, which more correctlyallocates steel within the overall structureto those areas where it is most needed.Even if the overall scantlings are some-what increased, it is important to note thatin some areas the corrosion margins may

be slightly lower than according to theprevious practice.

Another new and important feature inthe CSR is the coating performance standard

introduced. According to the rules alldedicated seawater ballast tanks and voiddouble side skin spaces are to have an effi-cient corrosion prevention system, such ashard protective coatings or equivalent.The coatings are to be of a light colour,i.e. a colour easily distinguishable fromrust which facilitates inspection.

IMO’s “Performance Standard for Protective

Coatings for Dedicated Seawater Ballast Tanks

of all Ships and Double-Side Skin Spaces of

Bulk” which will be discussed at theMarine Safety Committee Meeting(MSC81) and opting for approval andsubsequent adoption at MSC82 inDecember 2006, will be the referencestandard for the Common StructuralRules. SOLAS II-1/3-2 is expected to beamended accordingly at the same time.

Although the amended SOLAS II-1/3-2not will come into force by earliest by July2008, this performance standard will beapplicable for CSR vessels contracted forconstruction on or after the adoption date

of the revised SOLAS II-1/3-2The attending surveyor of the Society

will not verify the application of the coat-ings but will review the reports of the coat-ing inspectors to verify that the specified

shipyard coating procedures have beenfollowed.

A review of damage records for existingvessels shows that although the absolutenumber of incidents is not severe, the por-tion of the damages that are related tofractures is significant. This input hasbeen used as the basis for the Rule devel-opment and is reflected in the final Rulesthrough the increased design fatigue stan-

dard of 25 years North Atlantic (up from 20years worldwide for DNV Rules),increased scope for fine mesh finite ele-ments and requirements for specificdesign details in critical areas.

The new rules adopt a direct calculationmethod and include a direct criterion forultimate strength. This entails looking at thestrength of the hull girder for yielding,buckling and progressive collapse modes,effectively considering what it would takefor the hull to catastrophically fracture.

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Corrosion additionincluding owners extra

Required net thickness

New building In service

Wastage allowance

2.5 years diminution

Renewal thickness

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What DNVcan offer toowners andyardsDNV’s goal is to serve the industry in the imple-mentation process of CSR. We aim to do so withhigh competence in all our approval centres andthrough increased service level towards yards andowners.

While the DNV has been very active during the development of the CSR forOil tankers, and has delivered software to support these Rules for a long timealready, we are now also scaling up our activity world-wide to assist clients inimplementing the CSR for Bulk carriers. An extensive training program hasbeen implemented for all approval units, enabling our staff to be well pre-pared to provide efficient and local support to the industry.

DNV can offer dedicated presentations of the Rules to owners and yards.Information about the consequences compared to present DNV Rules is avail-able. DNV has also developed detailed training courses which include all thetechnical aspects of the new Rules and the background for the same. Thistraining can be tailor made based on clients wishes.

We have skilled and competent approval staff around the world prepared tosupport the designers in developing their new designs, optimized accordingto the new common procedures. >>

DNV Maritime

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Hull Inspection Manuals for Bulk carriersDeveloping tailormade “Hull Inspection Manuals” is a new servicefor bulk carriers and reflect the experience gained from theTanker industry where this service now have been in use for quitesome time.

Such manuals are developed in close cooperation with theowner’s organisation, ensuring that the owner’s quality standard,maintenance strategies, key procedures and experience are wellreflected. Similarly, the involvement of DNV hull experts ensuresthat our accumulated vessel and ship type knowledge is incorpo-rated. In the end, the owner will have a set of company- and ship-specific manuals that enable better control of the ships’ hull con-dition and thereby also the operating risks, maintenance costs andincome.

The inspection manual provides clear guidance on how to carryout hull structure inspections and helps your technical personnelto focus on critical inspection areas, evaluate findings, and reportconsistently on the hull’s condition all through:n Detecting deficiencies at an early stage.n Being able to document the ship condition.n Maintaining a uniform standard across the fleet.n Reducing off-hire.

New Nauticus software with unique support for CSRThe new rule requirements for Bulk carriers introduce a radicalshift towards more computerisation of the rule formulations and

structural assessment. Hence, good software support is critical forany Class to provide timely and rational support to ship-owners aswell as designers and shipbuilders. As a response to this, DNV’swell established Nauticus Hull® program has undergone a majorupgrade to provide efficient support for the new Rules.

Nauticus Hull is a powerful software package for the design andstrength assessment of ship structures. It provides a highly efficientenvironment for ship design, with capabilities ranging from simpli-fied rule-check and scantling calculations to advanced tools forextended calculation procedures, including wave load and finiteelement structural analysis.

In January 2006, DNV was the first company to launch completesoftware support for CSR for Oil tankers. During April 2006, DNVagain made a new release of its Nauticus Hull software, thus againbeing first, this time with software support for the new rules forboth ship types.

The software has been developed in close cooperation withmajor shipyards to ensure it supports the design process in a mostefficient way. Therefore, the software has been developed not onlyfocusing on cutting modeling and input time, but rather cuttingthe total design and approval time. Especially, new tools have beendeveloped to make Finite Element Analysis more efficient throughautomated post-processing and code-checking, as well as genera-tion of loads, net scantlings and boundary conditions.

Double Bottom – Longitudinal Connections.

Example illustration from Hull Inspection Manual.

Inner and outer bottom longitudinals connection to transverse bulkhead

and adjacent floors with associated brackets.

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Unique efficiency for strength assessment by FEA.

Nauticus Hull compartment plan and loads shared among all applications and across several cross sections.

n Hull girder requirements

n H-ULS (hull girder ultimate

capacity)

n Yielding

– Local pressures

– Intact and flooding

n Buckling

– DIN Standard

n Steel coil

n Grab loading

n Minimum scantlings

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DNV welcomes the fact that the newCommon Structural Rules have beendeveloped using a consistent engineeringapproach that applies advanced analyticaland numerical methods based on engi-neering first principles to establish therequirements. This is in line with how theDNV Rules have been formulated for longtime already. However, similar to the DNVRules, also for CSR empirical and pre-scriptive requirements based on practicalshipbuilding considerations has beenincluded where appropriate.

In short, CSR may be summarized to yieldthe following characteristics:n Rules covering structural requirement

for Bulk Carriers and Tankers. n A Rule set utilising state of the art com-

putational methods for more extensivedirect strength calculations (FiniteElement Analysis).

n Vessels built to CSR shall have overallsafety of the hull structure equivalent toor better than that currently achievedby any current rules by any Class society,as illustrated in the figure below:

The reason for introducing CSR may besummarized as follows:n To obtain improved control over the

minimum safety level during the opera-tion phase.

n To eliminate competition between classsocieties with respect to structuralrequirements and standards.

n To employ the combined experience andrecourses of all IACS societies to developa single standard, or set of Rules.

n To ensure that a vessel meeting this newstandard will be recognised by theindustry as being at least as safe androbust as would have been required byany of the existing Rules.

What is CSR and why CSR?Many of the existing rules of IACS Class societies are largely prescriptiveand a result of an evolution from purely empirical requirements to acombination of empirically and theoretically derived requirements thatcompensate for the limitations of solely experience based rules.

IACS CSR

Individual society Rules

Requirements

Safe

ty l

evel

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In summary, the new rules offer severalobvious benefits for the shipping industry:n The new Rules will allow shipbuilders

and designers to work with one com-mon set of Rules, instead of one setfrom each class society. All IACS soci-eties will cooperate to maintain a singleRule set.

n More transparent technical backgroundof the Rules.

n The intention of the new Rules is toencourage the design and constructionof robust oil tankers and bulk carriers toeliminate competition on scantlings.

n Common Structural Rules compliantships will be designed to rigorous analyt-ical criteria.

n Extensive prescriptive requirementshave been put into effect with respect tothe application of the new CommonStructural Rules and the manner inwhich the central Finite Element analy-sis is undertaken so that consistency inapplication and common scantlingsresult.

n Stringent and clarified requirements tocritical areas.

n The minimum fatigue design life hasbeen upgraded from the 20 year world-wide trading to 25 year North Atlanticwave environment.

n The Rules include design standards forthe net scantlings of a vessel meaningthat the renewal thicknesses for the inservice time is checked and known atthe newbuilding stage.

n The corrosion additions that have beenestablished take into account the loca-tion and the environment to which thestructural member’s surface is subjected.

Benefits of CSR The new Common Structural Rules represent a significant step forwardin the establishment of technical standards that will result in a newgeneration of robust, safe ships.

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Impact of new Rules on actual designs

and the design processThe IACS Common Structural Rules forBulk Carriers will provide benefits to theshipyards in terms of the number of Rulesets and software packages they need tobecome familiar with. Whereas the exist-ing regime provides ten sets of Rules, thenew regime will provide only one. Anothereffect of common Rules is that the chanceof the Classification Societies being playedoff against each other in a process that

leads to unsafe scantling optimisation willalso be avoided.

The application of the CSR to existingdesigns shows that there will be changes.They will influence steel weights anddesign details. Compared to current DNVdesigns, typical increases are in the rangeof 3–4 per cent and occasionally evensomewhat higher.

The change in steel weight and scant-lings depend on the size of the vessel, typeof profiles used and degree of high tensile

material. In general, the majority of thechanges are seen in the cargo hold regionand, to some degree, the forward regionof the vessel.

For the cargo hold region, the newRules are seen to give a slight increase inhull girder sectional modulus – mainlydue to the new Ultimate Limit Statecheck. Further it can be noted that certainincrease in deck longitudinals, plate thick-ness of lower stool, lower part of hopperplating, inner bottom, side shell plating,

Practical consequences of CSRThe IACS Common Structural Rules for Bulk carriers will providebenefits to the shipyards a well as to the shipowners. The new Ruleswill result in more robust ships, with an increase in steel weight.

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1) Longitudinals in way of the hopper tank at shell are most exposed to

fatigue cracks. CSR require 25 years operationel life in North Atlantic.

2) Increased safety factor for single side shell according to Solas XII.

1

2

>>

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Fatigue check of inner bottom plating connection

with lower stool and hopper sloping plating.

1) Mandatory strengthening for grab loading.

2) Fatigue check of lower stool and corrugated bulkhead

connection.

1

2

Fatigue check of main frame connection to hopper sloping

plating and improved steel grade for bracket and adjacent

side plating.

IACS UR S21 (Rev.4) for Hatch Covers and Hatch Coamings.

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Corrosion margins for Bulk carrier according to CSR (denoted “JBP_tc” in the figure).

bottom plating, and webframe plating dueto buckling and yielding, and side and bot-tom longitudinals due to fatigue can beexpected.

It is further seen that, although high ten-sile material may be used, this material can-not be fully utilised in areas dominated bydynamic stresses due to the higher fatiguestandard. This is particularly so for NV36steel. A typical example is the deck area,where the dynamic loads account for twothirds of the total loading and, consequently,the fatigue requirement limits the allow-able stress level.

The figures on previous page indicatesome critical areas with stringent require-ments in the new Common StructuralRules.

Impact of new Rules on Ships in ServiceThe CSR will result in more robust ships.When properly operated and maintained,the through-life repair and maintenancecosts should be reduced and safety marginsincreased. The most significant impact ofthe Rules from an operational point ofview is that the wastage allowance will bethe same regardless of which classification

society has classed the vessel, and will beavailable upon delivery of the vessel. Withthe new net thickness philosophy, theowner can even determine the allowanceprior to contracting the vessel and henceuse this to determine if additional owner’sextras are to be added. As all the calcula-tions performed during the Newbuildingassessment are on the net scantling, no fur-ther calculations are required to be per-formed in service to determine the allow-able wastage.

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Application of CSR andClass notationsCSR for Bulk Carriers are applicable for vessels >90 m signed for construction after April1, 2006. A Bulk Carrier is in this context defined as ”A sea going self-propelled shipwhich are constructed generally with single deck, double bottom, hopper side tanks andwith single or double side skin construction in cargo length area and intended primarilyto carry dry cargoes in bulk.”

The vessel type covered includes single side skin and double side skin configurations:

The following cross sections are not covered by CSR, and should still be approved according to the DNV 1A1 Rules:

Hybrid bulk carriers, where at least one cargo hold is constructed with hopper tank and topside tank, are covered by CSR.

Clarifcation of the new Rule text and

DNV’s interpretation of the practical

consequences of the new Rules.

1. Will ship designed to the new rules be heavier

than the existing DNV designs?

One of the objectives with the new rules isthat they shall be at least as safe androbust as the existing vessels. It is intro-duced new hull girder ultimate limit statecriteria, a new net scantlings approachand in addition higher fatigue design life(25 years in North Atlantic operation).Based on this we expect a 3–5 % increasein steel weight. The change in steel weightand scantlings will, however, depend onthe size of the vessel, type of profiles usedand degree of high tensile material.

2. How is coating treated in the new rules?

Although the amended SOLAS II-1/3-2not will come into force by earliest July2008, this performance standard will beapplicable for CSR vessels contracted forconstruction on or after the adoption dateof the revised SOLAS II-1/3-2.

3. What about SOLAS XII “Additional safety

measures for bulk carriers” requirements which

come in to force July 2006?

For a vessel subject to CSR, SOLAS XII isautomatically covered. For vessels not sub-ject to CSR, but subject to DNV BulkCarrier Rules and with keel laying on orafter 1st of July 2006, the SOLAS XII

requirements are to be handled separately.

4. Will vessels complying with DNV

Nauticus(Newbuilding) meet the criteria of the

CSR?

No. For the Nauticus(Newbuilding)design parameter is 20 years world-widewhile 25 years North Atlantic is applied inthe CSR. In addition, different yieldingand buckling criteria is applied in CSR.

5. Will it be possible to modify an existing DNV

Nauticus(Newbuilding) approved vessel to

comply with the new CSR criteria?

Yes, but such modification would mostlikely enforce changes to the existingscantlings.

Changes in the approval process in

particular when the new common rules

are implemented.

1. Will approval procedures and site procedures

be unified or harmonised with the new rules?

No, the approval process and site proce-dure will not be further harmonised thanin the existing regime.

2. What measures are taken to ensure consistent

interpretation of the rules amongst the IACS

societies?

Two Project Teams have been establishedin IACS, consisting of two members fromthe permanent secretariat and 4 technicalexperts. These project teams will answer

questions and conduct the technicalassessment of potential inconsistent inter-pretations, which may eventually draw uprecommended Rule changes for approvalby the IACS Hull Panel.

3. Will DNV do approval of a vessel if she is

already approved according to CSR by another

IACS society?

As the design is already reviewed andapproved by an IACS member, no signifi-cant difference in scantlings is expected.However, in order to verify such expecta-tion, DNV will carry out full planapproval. If discrepancies are revealed thiswill be addressed in the appropriate IACSforum.

General discussion related to the new

Common Structural Rules.

1. Why change a system that has been in place

for more than 100 years?

Traditional prescriptive Rules were basedon empirical experience. They tended tofavour the side of caution and no explicitconsistent safety goals for the rules werestated. Irrespective of this they workedwell for many, many years. With the emer-gence of advanced structural and hydrody-namics computational methods, designersbecame able to improve designs signifi-cantly over the years while more preciselymeeting the rule requirements. In this waydesigners have been able to optimise ship

Frequently asked questions/industry concerns

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The questions and answers you find below areprovided with the purpose to clarify issues relatedto the implementation of the new Rules.

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designs with respect to construction andoperation.

In March 2001 ABS, DNV and LR jointlyannounced that they would work to estab-lish common criteria for ship structuraldesign, including hydrodynamic loads andcorrosion margins for standard ship types,beginning with tankers. The IACS JointTanker Project (JTP) and the newCommon Structural Rules for tankers arethe culmination of that project.

The IACS Joint Bulk Carrier Project(JBP) is a comparable development, fordouble and single side skin bulk carriers,undertaken by BV, CCS, KR, NK, GL, RSand RINA. Following initial developmentand harmonization of these two “pilotprojects”, IACS Council adopted theresulting Rules as IACS Common Rulesfor tankers and bulk carriers.

2. Are the tanker and bulk carrier rules based

on the same technical approaches and criteria?

The two projects started at differentpoints and have followed different pathsbut IACS has recognized that the two proj-ects must deliver a harmonized approachto the fundamental assumptions of hulldesign, particularly since the approachwill also provide the foundation for possi-ble future projects to establish commonstructural rules for other ships types.

Three class societies – ABS, DNV andLR – jointly worked to develop the newtanker rules. The other seven IACS mem-ber societies jointly worked to develop thenew bulk carrier rules.

The two projects have progressed inparallel in order to proceed as quickly aspossible. In the same manner that currentclass rules may take different philosophi-cal and engineering approaches to theestablishment of Rule requirements, thenew Common Structural Rules for tankersdiffer in some respects in their technicalapproach to those that have been devel-oped for bulk carriers.

Both approaches are technically sound.Neither is considered technically superiorto the other. Each will result in common

scantling requirements for a given design.Both are expected to result in vessels thatare at least as robust as those currentlyapproved to existing Rules. And thedegree of transparency regarding thetechnical justifications for the Rules ismore open and complete than at any timein the past.

The IACS members have recognizedthat for clarity and simplicity, the harmo-nization of the different technical app-roaches taken by the Common StructuralRules for tankers and those for bulk carri-ers is ultimately desirable.

A long term plan has been adopted tooversee this transition. The key element ofthis project is that a vessel built to thefuture harmonized rule sets will be direct-ly comparable to a tanker or bulk carrierbuilt to the first iteration of the CommonStructural Rules that entered into forceon 1st April 2006, as amended in theinterim to reflect experience.

3. Will the text of the Rules be the same for all

societies and therefore will the result, i.e. the

scantlings, be the same?

The new Rules have been developed toachieve the stated objective of eliminatingthe competitive element from the establish-ment of structural standards by producingcommon scantling requirements, regard-less of which IACS member society is select-ed to class the vessel. The text adopted intothe individual Rules of each society is iden-tical and future updates will also result inidentical amendments to that text.

4. Are the new Rules based on those of any one

society?

The development of the CommonStructural Rules drew on the collectiveexperience of the societies engaged in therespective tanker and bulk carrier projectteams, supplemented in inter-project dis-cussions and development with all IACSmember societies. The new Rules are notdirectly based on the Rules of any onesociety. They are reflective of the com-bined knowledge of all the memberswhich have contributed to their develop-

ment. The Common Structural Rules dif-fer significantly from existing Rules.Therefore, making direct comparisons onan item specific basis is difficult and likelyto give rise to misunderstandings or misin-terpretations.

5. How to handle a contract signed prior to 1st

of April 2006 where construction will not

commence until 2007?

Ships or series of ships signed for construc-tion prior to 1st of April 2006 is not sub-ject to CSR even if the construction is tak-ing place later than 1st of April 2006. Suchships will be subject to current DNV Rules.

6. A ship building contract signed prior to 1st

of April 2006 includes options for additional

ships. To which rules should the optional ships

be constructed?

Options included in contracts signedprior to 1st of April 2006 are not subjectto CSR if the option is exercised within ayear of the initial contract signing.

7. A ship building contract signed before 1st of

April 2006 is amended. To which Rules should

the additional ships be constructed?

Amendments are subject to the Rules inforce at the date of signing the amend-ment. If the amendment is signed on orafter 1st of April 2006, the ships are sub-ject to CSR.

8. How will the new common Rules be

maintained in the future so that they take

account of in-service experience and new

technologies?

Amendments is subject to the Rules in thesame way that existing Rules are updated,expanded or otherwise modified to reflecta deeper understanding of technical issuesand the proven results of applied researchand analysis, so too will the CommonStructural Rules be amended in future sothat they will embody the technically vali-dated knowledge that becomes available.

Relevant issues related to in-serviceexperience with the new Rules will also be

shared within IACS, which has establishedan internal mechanism for the evaluationof relevant data. Two additional staff posi-tions have been created within IACS tocoordinate this process and technical pan-els of experts for the tanker and bulk car-rier rules respectively have been estab-lished. It is these panels that will conductthe technical assessment of the data anddraw up the recommended Rule changesfor approval by the IACS Hull Panel.

9. Is it likely that IACS will introduce common

survey Rules?

IACS is currently developing new UnifiedRequirements for the survey of new con-struction.

10. Is it likely that IACS will introduce

common Rules to other areas and ship types?

It is possible, depending upon the successof the new tanker and bulk carrier com-mon rules, that consideration could begiven to other ship types and possibly tothe machinery rules.

Sources: DNV interpretations, JTPRules.com

and IACS Press release of 28th of March,

2006.

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