< Previous | Contents | Next >
Section 2 Principles of Design and Construction
201. Propulsion units
1. With regard to their type, number, size and arrangement, propulsion units are to be designed in ac- cordance with the intended duties of the submersible.
2. Externally mounted propulsion units are either to be designed for the maximum permissible diving pressure of the submersible or they are to be pressure equalized.
3. Propulsion engines for submersibles are to be designed for intermittent and continuous service.
4. When travelling on the surface, the air supply to internal combustion engines shall pass through an air mast. Exhaust lines are to be led out through the pressure hull via a double, pressure-tight shut- off device. The requirements to be met by closed-circuit propulsion systems are to be agreed with this Society in each individual case.
5. Electric propulsion motors are to be designed in accordance with Pt 6 of Rules for the Classification of Steel Ships.
6. If the propulsion engine is located inside the pressure hull, the thrust block should also be located in the same space.
7. Shaft penetrations through pressure hull walls should be fitted with a gland of proven type de- signed to withstand the maximum diving pressure.
8. Where necessary, propellers are to be shielded to avoid endangering divers and to prevent fouling.
9. Devices for controlling the engine speed and/or the direction of rotation are to be so designed that the propulsion engine can be stopped when they fail. The propulsion engines of autonomous sub- mersibles are to also be capable of manual control.
10. The propulsion equipment is to be fitted with a sufficient number of indicators and alarms to guarantee safe operation.
202. Manoeuvring equipment
1. Submersibles are to be equipped with suitable devices to ensure that the vehicle possesses the nec- essary manoeuvrability both on the surface and when submerged.
2. Horizontal and vertical rudders are to be designed to withstand the maximum loads generated by the pitching motions of the submersible and the wash of the sea when surfaced and by the steering
forces experienced when submerged. The effective stress in the rudder
times the yield stress.
3. Autonomous submersibles are to be equipped with at least one main
stock shall not exceed 0.5
and one auxiliary steering
gear. With the vehicle travelling at full speed, the main steering gear is to be capable of putting the rudder from 35 on one side to 30 on the other within 28 seconds.
4. Horizontal rudders are to be so designed that, over the whole speed range and under all loading conditions, the desired depth can be maintained.
5. Horizontal rudder systems are to be equipped with a second power supply which meets the require- ments of preceeding Pars 2. and 4. It is to be possible to switch from the main to the alternative power supply from the control stand.
6. The slewing mechanisms of propulsion units which are also used for manoeuvring are subject to the same requirements as rudders.
7. The main and emergency control stands of autonomous submersibles are to be fitted with indicators showing the positions of vertical and horizontal rudders. All other submersibles are to be equipped with at least one position indicator each for the vertical and horizontal rudders. In addition, suitable indicators are to be fitted which signal any malfunction or failure of the steering gear. 
