design of a pleasure craft with catamaran hull
TRANSCRIPT
![Page 1: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/1.jpg)
Design of a Pleasure Craft with Catamaran Hull
NA 18 Htike Aung KyawNA 32 Kaung Zaw HtetNA 38 Paing Hein Htet TinNA 42 Htaik Thu Aung
Supervised by Daw Khin Khin Moe
![Page 2: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/2.jpg)
• We chose this project title because there are no former projects from our university which relates to this field of study.
• This type of craft has better stability and faster speed than the other conventional types of ship.
• It can give one’s pleasure or comfort, luxury, attract most people.
![Page 3: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/3.jpg)
Chapter-1 Introduction Chapter-2 Types of Pleasure Crafts, Yachts
and Catamarans Chapter-3 Designing Concepts and Detail
Design of Pleasure Craft with Catamaran Hull
Chapter-4 Rules and Regulations which this Pleasure Craft Complies
Chapter-5 Design Calculations for Pleasure Craft
Chapter-6 Model Making Chapter-7 Conclusions and
Recommendations
![Page 4: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/4.jpg)
This project concentrates on the concept on an easy to handle pleasure motorboat constructed as a catamaran.
Seeking the current market situations, there aren’t any places for catamarans here in Myanmar.
Catamarans are used as luxury crafts mostly in Australia and New Zealand, can also be found in America.
![Page 5: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/5.jpg)
![Page 6: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/6.jpg)
General DefinitionGeneral Definition Multihulls
Crafts with more than one structural body Usually of two, three or five hulls, namely
Catamaran, Trimaran and Pentamaran Pleasure Crafts
Vessels that are used for sports, fishing or recreational purposes only
Do not operate for any financial gain to the owner
![Page 7: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/7.jpg)
![Page 8: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/8.jpg)
Yachts Motor Yachts Pleasure Crafts/Luxury Crafts Catamarans Types of Catamaran Hull Forms
![Page 9: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/9.jpg)
A recreational boat. Maybe of sail- or
power- boats. Yachts are different
from working ships mainly by their leisure purpose.
Motor yachts generally fit into the following categories: Day cruiser yacht (no
cabin, sparse amenities such as refrigerator and plumbing)
Weekender yacht (one or two basic cabins, basic galley appliances and plumbing)
Cruising yacht (sufficient amenities to allow for living aboard for extended periods)
Sport fishing yacht (yacht with living amenities and sporting fishing equipment)
Luxury yacht (similar to the last three types of yachts, with more luxurious finishing/amenities)
![Page 10: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/10.jpg)
• Pleasure craft includes motor yachts, sailing yachts generally owned by private individuals; few are large enough to be regarded as ships. • They provide the maximum safety, comfort and entertainment for the passengers. • Maintaining stability of the hull is important. • No extreme of luxury can offset a simple case of sea sickness.
• A ship consisting of two hulls, joined by some structure, the most basic being a frame.• Catamarans can be of sail- or engine-powered.• The twin-hulled sailing or motor boat has since become a popular pleasure craft, largely because of its speed and stability.
![Page 11: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/11.jpg)
PONTOON OR HYDROAIRY TYPE
BASIC CATAMARAN• When talking about catamarans, we are not speaking of just one type of hull, but merely a whole hull category with many different types of constructions and optimization for different purposes.
• Variations of hull forms exist.
SWATH(SMALL WATERPLANE AREA TWIN HULL)
![Page 12: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/12.jpg)
Type-A Type-C Type-EType-B Type-D Type-F
Type-G Type-H Type-I Type-J A. Australian type with symmetrical sponsons*, fine entry, medium-square tunnel, low dead rise.B. Sailing-boat type symmetrical, round-bilge and tunnel, deep forefoot, no strakes.C. Asymmetrical sponsons with low dead-rise bottoms and no-trip chine, medium height square tunnel.D. Split monohull with narrow, low square tunnel with high attack angle at bows.E. Super-slim sponsons with medium-to-high tunnel, fine entry, designed to be used on protected waters.F. SES (solid side skirt) hovercraft with low tunnel and skirts at bow and stern.G. Kenton cat type with low round tunnel and round bottoms, tunnel lifting at bow.H. HySuCat with one main foil and two trim foils, high dead-rise bottoms and medium-high tunnel.I. Bobkat with round, asymmetrical sponsons, high tunnel with tunnel-chines and bow steps.J. Bobkat with HySuCat foils.
![Page 13: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/13.jpg)
Aspects A B C D E F G H I J1. Low Vertical Acceleration – Sponsons
2 7 5 4 9 9 5 6 7 8
2. Low Vertical Acceleration – Tunnel
3 3 3 1 5 9 1 6 7 9
3. Inward banking in Turns 1 1 9 7 6 4 5 7 9 94. Non-broaching in Following Seas 2 3 6 7 4 6 7 5 8 85. Non-weaving in Quartering Seas 8 8 2 3 4 7 7 3 8 86. Resistance to Barrel-Rolling 1 5 9 3 7 7 7 5 9 97. Load Carrying Ability 5 5 6 7 2 3 8 5 6 78. Transverse Stability 6 6 7 3 4 3 4 7 7 79. Pitching Stability 4 5 6 7 4 3 6 7 7 810. Dry Ride in Small Chop 6 6 6 3 7 2 2 7 7 711. Economy at Planing Speeds 8 4 7 4 2 9 7 9 6 812. Economy of Construction 8 9 8 7 5 1 6 7 9 7Total Score 54 62 74 56 59 57 65 74 90 9
5
![Page 14: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/14.jpg)
Length overall – 15 m Length in waterline – 13.904 m Breadth (maximum) – 6.75 m Depth – 2.1 m Draught, at design waterline – 0.7 m Block Coefficient – 0.516 Speed – 15 knots Displacement – 20.42 tonnes Classification – Lloyd’s Register
of Shipping No. of Passengers – 6 Propulsion – 2xVolvo Penta IPS 600 Power – 2x320kW (2x435hp) Fuel & Fresh Water Capacity– 3387.131 liters,
680.045 liters
![Page 15: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/15.jpg)
The principle dimensions of this design ship are derived from Thidar Catamaran (a 23.837m Catamaran, the only two catamarans built in Myanmar as Thidar I & Thidar II).
The General Arrangement Plans is adopted from a graduation project by Juri Karinen, Lahti University of Applied Sciences, Finland, named as eCAT hybrid.
Lines Plan of Thidar CatamaranLines Plan of Thidar Catamaran
![Page 16: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/16.jpg)
1. From the Lines Plan of Thidar catamaran, we collect data to create the offset table. (Note that there may be errors up to 20 millimeters in full scale).
2. From this offset table, we use Geo-Sim method to create an offset table for a 15m Catamaran.
3. Notice that Thidar catamaran is a round bilge hull and our design is a chine hull catamaran. We create the chine hull using the values of the offset table for the 15m Geo-Sim catamaran as the limits.
4. In creating a chine hull, first we draw it by hand, adjusting the limits. Again, we collect offset data from the hand drawing and create a 3D marker data which will later be imported to Maxsurf Pro software.
![Page 17: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/17.jpg)
5. Marker data is created using Microsoft Excel Spread Sheet and saved in a “.txt” format.
6. On markers window in Maxsurf Pro, Open the saved “.txt” marker data.
7. Prefit software is not used as it will give and undesirable result while importing catamaran hull marker data.
8. Create multiple surfaces, bond them, trim them as necessary. Transverse stiffness is set to 2 as we are creating a chine hull form.
9. After quite enough fairing is done, the required hull form is obtained in a “.msd” format.
![Page 18: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/18.jpg)
Markers from Offset Table seen in Perspective View in Maxsurf
![Page 19: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/19.jpg)
10. To create Lines Plan and GA Plan, we used AutoCAD software.
11. It is easy to bridge Maxsurf and AutoCAD software. The hull form that we created in Maxsurf can be exported as a “.dxf” format. This is a data exchange format that most CAD modeling software know. The export file can now be opened in AutoCAD.
12. Unnecessary lines are deleted and the lines from each view is arranged in a new file after which it is saved. A Line Plan in “.dwg” format is achieved.
13. GA Plan is drawn similar to eCAT hybrid.
![Page 20: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/20.jpg)
14. For Calculations, we will calculate with aid of software and verify by hand calculation wherever possible.
15. For the first step of powering prediction, we use the resistance data obtained from NavCad.
Lines Plan
![Page 21: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/21.jpg)
It can be used both in Protected Waters and Sea-going.
As it has a low draft, it has no problems in going shallow water, but it is designed mainly to go offshore, coastal area around Myanmar.
![Page 22: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/22.jpg)
![Page 23: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/23.jpg)
![Page 24: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/24.jpg)
![Page 25: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/25.jpg)
![Page 26: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/26.jpg)
3D Rendering Video
![Page 27: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/27.jpg)
4 View Windows in 4 View Windows in MaxsurfMaxsurf
![Page 28: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/28.jpg)
![Page 29: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/29.jpg)
![Page 30: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/30.jpg)
NavCad Prediction Results using Gronslett (Catamaran)
Prediction Method
![Page 31: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/31.jpg)
Propulsion is by twin installation of Volvo Penta IPS 600. Much improved efficiency, higher top speed, reduced fuel
consumption/extended range, and great acceleration Low-speed maneuvering is easy, and high speed handling is a really
fine Onboard comfort is greatly enhanced thanks to much lower
levels of sound and vibrations Installation is greatly
simplified More space available for
accommodation Improved safety and quality Ease of service, and a
complete system supported by one supplier
Improved overall environmental care
![Page 32: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/32.jpg)
• Increased blade area vs. output, smaller propeller diameter and large gear ratio• No side force
• Half propeller loading, means half tip losses and minimized cavitations
• Horizontal shaft and thrust• Counter-rotating creates no rotational losses
![Page 33: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/33.jpg)
![Page 34: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/34.jpg)
There is another interesting fact in our designed ship.
It is no other than the sewage system. There are two toilet bowls in our designed ship but there is neither retention tank nor a sewage treatment plant.
This is because we use INCINOLET, the electric incinerating toilets.
INCINOLET uses electric heat to reduce human waste (urine, solids, paper) to a small amount of clean ash, which is dumped periodically into the garbage.
![Page 35: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/35.jpg)
SOLAS Rules and Regulations for the Classification of
Yachts and Small Craft (Lloyd’s Register of Shipping)
![Page 36: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/36.jpg)
Our design ship will go in Sea Area A1 only. Below, we will define basic ship requirements
(equipments required to be fitted onboard) by SOLAS. Chapter IV, Part C & Chapter V
Sea Area A1 is between 30~40 nautical miles from land, i.e, an area within the radiotelephone coverage of at least one VHF coast station in which continuous DSC alerting is available.
DSC (Digital Selective Calling) is a technique using digital codes which enables a radio station to establish contact with and transfer information to another station.
![Page 37: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/37.jpg)
Equipments No. Required
VHF with DSC x1
VHF with DSC receiver x1
NAVTEX receiver x1
Float-free satellite EPIRB x1
Radar Transponder (SART) x2
Hand-Held GMDSS VHF Transceiver x1
VHF - Very High FrequencyNAVTEX - Navigational TelexEPIRB - Emergency Position-Indicating Radio BeaconSART - Search and Rescue ( Radar ) TransponderGMDSS - Global Maritime Distress and Safety System
![Page 38: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/38.jpg)
On 1st July 2002, some new regulations came into force, which directly affect the pleasure boat users.
These regulations are part of Chapter V of the International Convention for the Safety of Life at Sea, otherwise known as SOLAS V.
Most of the SOLAS convention only applies to large commercial ships, but parts of Chapter V apply to small, privately owned pleasure craft.
If a boating accident is involved and it is subsequently shown that the users have not applied the basic principles outlined here, they could be prosecuted.
![Page 39: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/39.jpg)
Many large ships rely on radar for navigation and for spotting other vessels in their vicinity.
So, whatever size of the boat is, it’s important to make sure that it can be seen by radar.
Regulation V/19 requires all small craft to fit a radar reflector ‘if practicable’.
If the boat is more than 15m in length, it should be able to fit a radar reflector that meets the IMO requirements of 10m2.
If the boat is less than 15m in length, it should be fitted with the largest radar reflector possible.
Whatever size of the boat is, the radar reflector should be fitted according to the manufacturer’s instructions and as high as possible to maximize its effectiveness.
![Page 40: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/40.jpg)
Regulation V/29 requires the pleasure boat users to have access to an illustrated table of the recognized life saving signals, so that they can communicate with the search and rescue services or the other boats if they get into trouble.
If the boat is not suitable for carrying a copy of the table on-board (because it’s small or very exposed), they must make sure that they have studied the table before they go boating.
Larger boats should keep a copy on-board.
![Page 41: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/41.jpg)
If the yachts and small crafts are to be registered under the Lloyd’s Register of Shipping class, the rules and regulations must be applicable.
Some of the main important factors to consider are listed below. For constructional safety arrangements,
Bulkheads Hatches and Doors Portlights and Windows Guard Rails Ventilations Fire Protection Chains, Anchors and Mooring are to be considered.
For machinery and electrical installations, Engine Seatings Pumps and Piping Systems Electrical Installations Electrical Distribution Systems Batteries Lightning Conductors are to be considered.
![Page 42: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/42.jpg)
Stability Calculations Resistance and Powering Calculations Strength Calculations
![Page 43: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/43.jpg)
Hydrostatic Curve Calculation The density of water used is 1.0252 tonnes/m3
The hydrostatic particulars at the draft of 0.7 m are: Displacement – 20.42 tonnes LCB – 1.105 m (aft of midship) VCB – 0.451 m WPA – 45.362 m2
LCF – 1.344 m (aft of midship) KML – 26.071 m KMT – 10.564 m WSA – 67.691 m2
TPC – 0.458 tonne/cm MTC – 0.409 tonne-m/cm
![Page 44: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/44.jpg)
![Page 45: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/45.jpg)
Displacement vs. KN Values
![Page 46: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/46.jpg)
As our design ship is small, every single loads acting on it can cause serious stability issues.
Thus, even small loads like chairs and accessories aren’t neglected.
The following load case is used to determine large angle stability.
![Page 47: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/47.jpg)
![Page 48: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/48.jpg)
For most vessels, the GZ Curve must satisfy the criteria stating that the angle where maximum GZ occurs must be above 30 degrees.
But for multi-hulls which have only small heel angles, maximum GZ might occur on angles less than 30.
For our design ship, Max GZ of 2.127m occurs at the angle of 21.9 degree.
HSC Code states that multi-hulled vessels must have Max GZ at the angles greater than 10 degree.
![Page 49: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/49.jpg)
![Page 50: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/50.jpg)
In still water condition, we can see that the boat is trimming by aft.
The draft at AP is 0.06m more than the average draft. Both LCB and LCF are located aft of the midship. The immersion is 0.468 LT/cm. This is because the boat is
relatively small. The deck has a maximum inclination of 0.6 degree. This
isn’t much. This deck inclination is cause by the trim of the boat,
having the same trim angle of 0.6 degree. Trim is by stern.
![Page 51: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/51.jpg)
Sectional area curve for still water condition
![Page 52: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/52.jpg)
Resistance Calculation/Prediction in catamaran is more difficult and complicated than most conventional mono-hull.
Generally saying, catamaran resistance is twice the individual hull resistance, plus an added drag due to the interference of the hulls with each other.
Solutions cannot be generalized by one simple formula but varied in accordance with specific configurations of catamaran hull forms and their separation.
![Page 53: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/53.jpg)
Viscous interference
Due to asymmetric water flow around each hull.
Wave interference Due to interaction
of the two separate wave systems in the tunnel between the hulls.
![Page 54: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/54.jpg)
Insel and Molland (1992) proposed that the total resistance of a catamaran should be expressed as:
CT CAT = (1+ ϕk) σCF + Cw They also state that for the practical
purposes, σ and ϕ can be combined into a viscous resistance interference factor , where
(1+ ϕk) σ = (1+ k). Thus, total Resistance Coefficient;
CT = CF + CR = (1 + k)CF + Cw
![Page 55: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/55.jpg)
Where,CF = Frictional Resistance Coefficient can be calculated by the formula of
CR = Residuary Resistance Coefficient (Residuary resistance coefficient is found by using Froude – CR diagrams) CW = Wave Resistance Coefficient = Viscous Resistance Interference Factor = Wave Resistance Interference Factor
It may be noted that for demi-hull in isolation, = 1 and = 1, and for a catamaran, can be calculated as:
Form factor (1+k) is obtained using regression method, plotting Fn
4/CF vs. CT/CF, using an index of m=4.
DEMIFCkTCCATFCkTC
WDEMICWCATC
])1([
])1([
2)2(log
075.0
nRFC
![Page 56: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/56.jpg)
Myanmar Maritime University
Marine Hydrodynamics CentreLm 1.364Ls 15
Length Ratio 11
Corresponding Speed Vm=Vs*(Lm/Ls)^0.5
(Lm/Ls)^0.5 0.301551543
Ship Speed Ship Speed Corresponding Speed Corresponding SpeedRt m
(knots) (m/sec) of Model (knots) of Model (m/sec)6 3.09 1.81 0.93 1.422927 3.6 2.11 1.09 2.794628 4.12 2.41 1.24 5.0952579 4.63 2.71 1.4 7.71465
10 5.15 3.02 1.55 13.1590111 5.66 3.32 1.71 19.83912 6.18 3.62 1.86 30.5116513 6.69 3.92 2.02 39.1844414 7.21 4.22 2.17 39.2212215 7.72 4.52 2.33 39.55348
![Page 57: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/57.jpg)
Finding Form Factor (1+k) using Regression Method
v (m/s) RT (N) Rn = vL/ν CT=RT/(0.5ρSv2) CF=0.075/(log Rn -2)2 Fn=v/(gL)0.5 CT/CF Fn4/CF
0.931395 1.42292 1406099.799 0.005603246 0.004358935 0.263591832 1.285462 1.107509
1.086628 2.79462 1640449.765 0.008085155 0.004221568 0.307523805 1.915202 2.118562
1.241861 5.095257 1874799.731 0.011286201 0.004107756 0.351455777 2.747534 3.71431
1.397093 7.71465 2109149.698 0.013501838 0.004011145 0.395387749 3.366081 6.092907
1.552326 13.15901 2343499.664 0.018654555 0.003927582 0.439319721 4.749629 9.484131
1.707558 19.839 2577849.631 0.023243209 0.003854219 0.483251693 6.030588 14.15002
1.862791 30.51165 2812199.597 0.030037575 0.003789025 0.527183665 7.927522 20.38545
2.018024 39.18444 3046549.564 0.03286916 0.003730501 0.571115637 8.810923 28.51865
2.173256 39.22122 3280899.53 0.028367868 0.003677518 0.615047609 7.713863 38.9117
2.328489 39.55348 3515249.497 0.024920907 0.003629199 0.658979581 6.866779 51.96095
![Page 58: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/58.jpg)
![Page 59: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/59.jpg)
Compare principle particulars of our model to the models tested by Molland A.F.
Length (m) 1.273L/ 1/3 5.110L/B 6.816B/T 2.935CB 0.5108WSA (m2) 0.588S/L 0.16 The model 4b shows the most
nearest values, thus the related values of 4b will be chosen.
![Page 60: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/60.jpg)
![Page 61: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/61.jpg)
Calculation can now be done using the 8 procedures shown in the book.
The results are as follows:vS (knots) vS (m/s) RTS (N) PES (kW)
6 3.0887 1148.3 3.557 3.6035 2780.78 10.028 4.1182 5655.08 23.299 4.633 13006.32 60.26
10 5.1478 16057.18 82.6611 5.6626 24839.44 140.6612 6.1774 39054.01 241.2513 6.6921 50877.41 340.4814 7.2069 50140.95 361.3615 7.7217 50151.29 387.25
![Page 62: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/62.jpg)
![Page 63: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/63.jpg)
Effective power for the ship speed of 15 knots is 387.25 kW.
Assume QPC = 65% or more QPC = PE/PD Delivered Power Required = 595 kW. One Volvo Penta IPS 600 engine could
deliver a power of 307 kW. Since two units are installed, Delivered
Power Installed = 614 kW.
![Page 64: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/64.jpg)
Other way of saying, Volvo Penta IPS 600 gives out a total of 614 kW delivered power.
QPC = 65% Thus the effective power of 399.1 kW can
be achieved. Effective Power for 15 knots = 387.25
kW. Power Installed > Power Required.
![Page 65: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/65.jpg)
Longitudinal Strength CalculationLoad Case (Weight Distribution with Forward and Aft Limits)
![Page 66: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/66.jpg)
![Page 67: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/67.jpg)
Materials used for fiber boat building, polyester resin, catalyst, accelerator, color pigments, gelcoat, wood and plywood, are to be of approved type by the Society for marine construction purposes.
Production of the craft can be either by hand lay-up or spray lay-up contact moulding techniques, and either of single-skin or sandwich construction or the combination of both.
Recommended that the sandwich construction for hull and single-skin construction for deck and other structures.
Moulds are constructed of suitable material and adequately stiffened to maintain their overall shape and fairness of form.
The scantlings are to be determined by interpolation of the values given in tables in the Rule Book with respect to the dimensions of the craft.
![Page 68: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/68.jpg)
The mechanical properties of a laminate, at a glass content by weight per layer of reinforcement of 0.3 are: Ultimate tensile strength = 85N/mm2, Tensile modulus = 6350 N/mm2, Ultimate flexural strength = 152 N/mm2, Flexural modulus = 5206 N/mm2, Ultimate compressive strength = 117.2 N/mm2, Compressive modulus = 6000 N/mm2, Ultimate shear strength = 62.0 N/mm2, Shear modulus = 2750 N/mm2, Interlaminar shear strength = 17.25 N/mm2 and Nominal laminate thickness per weight of reinforcement = 0.7mm per 300 g/m2.
The reinforcements are to be thoroughly impregnated with resin, and consolidated to give a maximum glass content by weight of reinforcement as follows: Chopped strand mat or sprayed fibres = 0.34, Woven rovings = 0.5, Unidirectional rovings = 0.54 and Cloth fabrics = 0.5
![Page 69: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/69.jpg)
The scantling of hull laminate is to be determined by the type of the craft, length and stiffener spacing. The values required are interpolated with respect to Length and Speed to Length ratio.
Basic Stiffener Spacing = 422.5 mm Bottom Shell Weight = 4988.7 g/m2
Side Shell Weight = 3756.9 g/m2
Keel Width = 662.5 mm Keel Shell Weight = 7483.05 g/m2
![Page 70: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/70.jpg)
In order to test resistance in towing tank, we need a fiber model. Fiberglass making is managed mostly by a couple dozens of
companies. Rare for individuals to make their own fiberglass products as there is a
difficulty to buy material required. For this project, a fiber model of approximately 1.5m in length is
required. We chose a scale ratio of 11. Model dimensions are shown below.LOA = 1.364 mLWL = 1.268 mB = 0.614 mT = 0.064 mvM = 2.33 m/sec for 15 knots of ship speed
![Page 71: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/71.jpg)
3-plywood sheets x4 2”x1” timber blocks x7’ Silicone sealants x2 Masking tape x1 No.3, P:36 Sandpapers x2 No.0, P:120 Sandpapers x3 Paper print-outs ½” Nails ¾” Nails 1” Screws Printer Hacksaw, Handsaw Pliers, Screw drivers Caulking gun Scissors, Knife, Rulers, Pen, Pencils, Permanent Markers, Tee and
Set-Squares
![Page 72: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/72.jpg)
Assembling stations and plating shells
Tools used in making wooden mouldStations cut out using hacksaw
![Page 73: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/73.jpg)
View from aft (Transom) of wooden mould
View from below (Fish view)
Profile view of wooden mould
![Page 74: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/74.jpg)
Cost of Timber mould is about 35,000 kyats. The usual way of fiber model making requires the
female fiber mould to be made first out of wooden primary mould.
Usually made with 6 laminates of chopped strand mat. Primary mould (Wooden) must first be sanded, applied
with poly putty and again sanded starting from the sandpaper no. of 40 to 1800.
For sandpapers of no. 400 and above, mould surface must be first sprayed with water before rubbing.
Gelcoat is painted or sprayed on this finished surface, lamination starting about an hour after.
![Page 75: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/75.jpg)
Chopped strand mat and polyester resin is used for lamination.
Mat laid, Resin applied, Rollers coated, avoided air gaps, released excessive resin.
6 layers of laminate, Female mould is ready. Final male model is made similarly using the female
mould as base, of 4 layers of laminate. This usual way can cost extra money if we make only one
model, leaving the female mould an exces. For a 4.5’x2’x7” model, could cost 250,000 Kyats or more. As one model is only needed and best if final male model
can be obtained without making a female fiber mould. Possible?
![Page 76: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/76.jpg)
We want the cost to be minimum as we only want one model for our project.
The company named Fusion Fiberglass agreed to make a final male model, costing only around 140,000 Kyats, where we won’t be able to get back the wooden primary mould.
The way they make isn’t usual. Although we couldn’t see the making of it with our eyes, they explained us how they made.
First, they put a tape fully around the primary mould. Then applied a really thick putty around it and let it dry.
They destroyed the wooden mould which is lying inside the putty, taking care not to harm the putty.
After peeling the tapes off, the putty now forms a female mould. Care must be taken in all stages afterwards. The male model is made just the same as the steps mentioned above.
![Page 77: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/77.jpg)
The required fiber model will be shown below. When Fusion Fiberglass delivered the model, they said
they have tested that the model is watertight. But we need to verify it. No lake or tank to test the model immediately. So, filled the model with water and see if there were leaks. None.
Finally, we got our model for just around 18000 Kyats. Fit wooden pieces for seating of dynamometer and
guiding arms, to test in towing tank. Dynamo must be fitted at CG both longitudinally and
transversely. LCG position calculated by Maxsurf and verified by
putting the model subjected to a tripping point, most likely to be edge of chair and seen balanced and stabled.
![Page 78: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/78.jpg)
![Page 79: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/79.jpg)
![Page 80: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/80.jpg)
Carriage Moving at a Speed of 2.33 m/sec, Related Ship Speed = 15 knots
![Page 81: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/81.jpg)
Conclusion In our project, detail definition relating to catamaran hull forms
and pleasure crafts, designed hull drawn with Maxsurf and its calculations, rules and regulations required and model making are included.
This project will help the development of using catamaran hull forms in ship industry in our country.
Chine hull form is used, intended to design a semi-displacement/semi-planing craft.
Displacement hull forms, useful for load carrying but slow speed. Planing hulls, designed for speed but power requirements are too high. Thus semi-displacement/semi-planing craft is selected for our design, pleasure craft.
Maxsurf, easy to use and fast calculation. Required catamaran hull form is created by bonding and trimming surfaces in Maxsurf. GA plan and Lines plan are drawn in AutoCAD.
![Page 82: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/82.jpg)
Stability calculations by Hydromax. Freeboard and Tonnage calculations are not necessary for this type of craft.
Resistance test in towing tank of MMU. Calculation by Insel and Molland Theory. Viscous and Wave Interferences present for catamaran resistance calculation.
Strength and Section Modulus by Lloyd’s Rules, interpolated linearly from given tables w.r.t length and speed to length ratio.
Model making chapter help understand basic model making and fiberglass technology.
FRP boat building, not widely used here. Locally manufactured boats are cheaper than imported
ones.
![Page 83: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/83.jpg)
In mass production of same design, fiber boat building is more beneficial and less costly compared to conventional boat building but if built only a few, the cost of making fiber mould is expensive and unprofitable.
Project points out superior facts of catamarans compared to monohull.
Further developments necessary. Fast ferries should be designed as catamarans. In depth study in this field would give stable, fast
and more profitable catamaran design.
![Page 84: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/84.jpg)
Recommendations No mother ship. Best if there is one. Calm water wave resistance, estimated by using theories and
previous test data by others. Preferred if all separation to length ratio of specific type of hull
form is tested. Resistance due to appendages neglected. Strength calculation incomplete. More rules and theories to study
for strength calculation of FRP crafts. Projects that can be derived using this as a base:
Change GA Plan to design a ferry boat of same size with a capacity of 35 to 50 passengers, more rules and regulations required.
Study resistance. Verify wave resistance w.r.t hull separation. Fit hydrofoils to form HySuCat arrangement. Install solar panels to form either electric only or diesel-electric
hybrid system or hydrogen fuel hybrid system. Study in depth of fiber catamaran building.
![Page 85: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/85.jpg)
“Design of a Pleasure Craft with Catamaran Hull” is just a graduation project, which we approached design aspects with the availability of data and resources all we could get. Took a lot of hard work to gather data as there is no former project to rely on and most data from the internet are incomplete and costly. We really hope this project could be the start or foundation of many projects relating this field of study for students in our country.
![Page 86: Design of a Pleasure Craft with Catamaran Hull](https://reader038.vdocument.in/reader038/viewer/2022102515/54bf00ec4a7959210c8b45fd/html5/thumbnails/86.jpg)