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Section 5 Calculations
501. Calculation
1. The 'working load' of the launch and recovery system comprises the weight of the submersible, in- cluding its equipment and ballast weights, the total weight of the crew at 75 kg each plus that of the fully equipped divers at 150 kg each. The 'dead load' is the weight of the launch and recovery system.
2. Regardless of the type of launch and recovery system and the size of the working load, the dimen- sional design of the launch and recovery system is to allow for a working load factor j of 2.7 and a dead load factor F of 1.5. It is assumed here that the use of the system in a seaway will be limited to significant wave heights of 2 m or less. Where it is proposed that launch or recovery operations should be performed in even more unfavourable conditions, previous agreement with this Society is necessary.
3. Calculations are to be based on the assumption that the angle of engagement of the hoisting and lowering strength member may be 12 off perpendicular in any direction.
4. The maximum static tensile stress imposed on steel wire ropes by the working load may not ex- ceed 12.5 % of the proven rupture strength of the ropes.
5. Where ropes made of natural or synthetic fibres are used, the maximum static tensile stress im- posed by the working load may not exceed 1/10 of the proven rupture strength of the ropes.
6. The stress limits
Steel Ships.
for components are specified in the Pt 9 of Rules for the Classification of