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Section 1 General
101. General
1. The requirements of this Chapter apply to the entire free flooding external structure of the sub- mersible including cladding, supporting structures and pressure hull fixtures.
2. The documents to be submitted to this Society for approval are listed in Ch 1, Sec 2.
3. The necessary tests and markings are specified in Ch 1, Sec 3 and Sec 4.
102. Design Principles
1. All free flooding parts of submersibles are to be designed and provided with openings in such a way that the spaces concerned can be fully flooded and vented.
2. When welding pressure hull fixtures such as diving tank mountings, operating equipment, stabilizing fins, rudders etc., care is to be taken to minimize the resulting internal stresses in the pressure hull. It is to be possible to inspect and preserve even those areas of the pressure hull adjoining fixtures.
3. The external structure of a submersible is to be so designed that parts of it can be crushed without damaging the pressure hull, and in addition steps shall be taken to exclude any likelihood of the vehicle being caught up by parts of its external structure. Anchors are to be so arranged that, when stowed, they are flush with the pressure hull.
4. Manipulators, claws, anchors and other items of gear which may be used to keep the submerged vehicle in position are to be so designed that they can be released or jettisoned in an emergency. Umbilicals and tow lines shall also be jettisonable. Release gear is to be operable even if the main power source fails. It is also to be designed to preclude accidental release or jettisoning. Jettisoning shall not cause any inadmissible heeling or trim conditions.
5. Submersibles with a diver's lockout are to be fitted with supports or runners which ensure a suffi- cient clearance between the bed and the vehicle.
6. Wherever possible, pressure hull wall penetrations for umbilicals and other pipes, hoses and cables are to be protected against mechanical damage by pressure hull fixtures or cladding.
7. Buoyancy appliances mounted externally on the vehicle are to be properly secured and protected.
8. The lifting point of the submersible is to be so designed and located that the vehicle can be hoist- ed and retrieved under the maximum permissible seaway conditions. The alternative lifting points are to be so designed and located that the submersible can be raised to the surface despite partial internal flooding.
9. The towing point is to be so designed and located that the submersible can be towed at the max- imum towing speed even under the most adverse operating conditions.
10. The external structure of submersibles is to be so designed and, where necessary fitted with gra- tings, to facilitate safe access to the vehicle.
103. Materials
1. Materials are to be suitable for the intended application and manufacturing process, and are to have been approved by the Society.
2. The manufacture, processing and testing of steels are to be in accordance with Pt 2 of Rules for the Classification of Steel Ships.
3. All other materials are to be manufactured and processed in accordance with recognized standards or to material manufacturer's specifications which have been examined and approved by the Society.
4. Materials for rigid ranges, are to have
5. Suitable proof is to
buoyancy tanks are to be suitable for the proposed pressure and temperature a low absorption factor and shall not suffer appreciable crushing under pressure.
be furnished of the characteristics of materials, e.g. a manufacturer's certificate.
104. Principles of Manufacture and Construction
1. Materials are to be processed by the correct procedures. Whenever necessary, tests of procedure are to be performed and production specimen produced prior to the start of manufacture.
2. Anchors, anchor chain cables/ropes and mooring ropes/hawsers are to be manufactured and tested in accordance with the Rules.
105. Calculations
1. Recognized mathematical procedures are to be followed in performing calculations relating to com- ponents of the external structure. The dimensional design of the external structure shall be such that, at the anticipated loads, the calculated stress is not greater than 0.6 times the yield strength.
2. For safety direction (
under collision conditions, an acceleration of 3 g should be applied in the longitudinal
X = 9.81 mĤsË ). In these circumstances, the external structure should be capable of de-
forming to absorb the impact energy without damage to the pressure hull.
