Section 2.3: Ship Building Flashcards
What is the role of the classification society in ship-building.
-A regulatory body that assist with the maintenance of standards, they provide survey work and provide some technical assistance.
- To oversee the naval architecture’s work during the build.
- At plan approval, the Class Surveyors will be checking that all construction meets with Class requirements.
- Size and spacing of strength members, the thickness of plating and design features that ensure the vessel complies with the minimum standards specified by the Societies for the size, type and dimensions of the hull.
- Class needs to comply with SOLAS and MARPOL.
What is IACS?
IACS, Internation Association of Classification Societies
12 Members:
1. ABS, American Bureau of Shipping
2. BV, Bureau Veritas
3. CCS, China Classificaiton Society
4. CRS, Croatian Register of Shipping
5. DNV, Det Norske Veritas
6. IR, Indian Register of Shipping
7. KR, Korean Register
8. LR, Lloyd’s Register
9. NK, Nippon Kaiji Kyokai
10. PRS, Polish Register of Shipping
11. RINA, Registro Italiano Navale
12. Turk Loydu
Ship Building Procedures
All materials have to be class approved.
The steel used for construction or repairs must come with a mill certificate.
Insulation between accommodation and engineering structures, this is important for fire prevention.
The vessel to be built in a zone that has minimum corrosion.
Prime coat over the ship’s bare steel, to prevent corrosion. 3 coats, Prime, Undercoat and a tie-coat inbetween.
Building underblocks (Small blocks assembly) is a benefit as machine welding can be done.
Better quality control, such as ultrasound.
Staggering plates that go together as a key fittings.
a) There is less utilisation of the building berth; therefore, more ships can be built by the yard in any given time frame.
b) The sections can be built under cover, providing a better finished article and less corrosion.
c) Sections can be turned to provide maximum down hand welding utilising greater use of an automatic welding machine.
d) More sections can be worked on at any one time, providing a shorter building period.
Details on sea trials
The stage where the ship’s equipment is put to the test.
- Generators
- Pumps
- Fans
- The ship’s cargo handling gear
- Firefighting equipment
- Lifesaving equipment
- Swing the magnetic compasses
- Compile the maneuvering data
(i) To satisfy the Classification Society of the ship’s ability to maneuver and control the main machinery.
(ii) To demonstrate to the Owner that the ship is able to perform as specified in the contract.
Depending on the type of vessel, sea trials can last from between 24 hours up to three or four days.
Need dispensation to conduct sea trials.
Sea trials can also be conducted in stages, taking the ship to sea on more than one occasion to carry out a range of different tests and exercises.
Tests conducted at sea trials
- Speed trials over a range of engine power outputs
- Various steering tests and maneuvering trials
- Speed of rudder movement
- Main engine fuel consumption evaluation under load
- Main engine control tests
- Emergency stopping trials.
- Turning circle data
- Anchor & windlass tests
- Performance of thrusters (if fitted)
- Trips and alarm systems on main engine
- Preferential trips on electrical circuits
- Emergency steering & emergency control systems
- Magnetic (Standard) compass adjustment
- Compass repeaters & follow up systems.
- Electrical navigation systems
- Suitability of lights & lighting by night
- Ability to darken ship for night navigation.
- Noise & vibration checks in accommodation and working areas.
- Fresh water generator tests (distillation unit)
New Building Specification and Repair Variations:
The relationship between the incidence of breakdown and frequency of repairs is critical in the new variation building specification being accepted.
- The need for repairs can be built in.
- Which leads to the admonition that when specifying new tonnage serious thought should be given to service duties, design characteristics, capabilities etc., of the ship and machinery in respect of ability to withstand wear and tear, and failure and breakdown, under maximum stress in service meeting duty requirements.
The following factors are important:
- Speed and consumption requirements
- Bad weather limiting conditions
- Special machinery servicing concession
- Provision for safe berthing
- Pilotage
Charter parties should be carefully considered with regard to vessel’s real service capabilities, i.e. performance compatible with age and condition as distinct from ideal described by as new trials performance.
The external surface of the hull of a ship will never be better or more efficient than it is when new. The hull surface deteriorates and the power required to drive the ship will increase through the years.
When drawing up the specification for a new vessel, the maximum power available in the main engine should not only be for sea trials, but to allow the vessel to proceed at maximum power another eight or ten years.
Both the main machinery and auxiliaries, performance tends to fall off due to wear and tear, and the effects of service conditions at some later time in the vessel’s life.
The shipbuilder, has to produce the lowest cost product to do the job required. The owner needs a ship which will perform as he requires for the life he requires without frequent failures. These two obliquely opposing requirements must be reconciled.
It is the Consultant’s / Superintendent’s job to do so by considering all the factors and arriving at the best compromise solution in terms of overall economics. The specification for the proposed vessel can then be defined with some hope that it will perform as intended. In saying this 1 acknowledge that ship operation is a long-term activity, and that forecasting the future economic climate is a chancy business.
Does the BWM system onboard need to be approved by IMO?
Yes.
What materials are vessel commonly build with?
Steel, with properties inbetween aluminium and carbon.
Steel components include:
- Carbon
- Manganese
- Iron
- Silicon
With these components within the steel, it would be easier to weld, therefore saving time and finally cost.
All materials used have to be class-approved.
Details on the ballast water managment system that is applicable to vessels now.
By 08 Sept 2024, all vessels above 400MT needs to be fitted with a class-approved ballast water system.
Which includes loading ballast through a filtering and sterilising system into storage and when deballsting to go through sterilisation before releasing out to sea.
Details on the welder.
- Preparation work. (Welder has to be approved)
- Materials to come from a reputable supplier. (able to issue Mill Certificate)
- Before work is being done, the contractor needs to prepare a procedure that covers all the requirements concerning the welding.
