Question.

With regard to ship construction details for watertight bulkheads

a) State the purpose of this type of bulkhead.

b) State how the bulkhead's are tested for water tightness.

If it is necessary to penetrate the bulkhead, precautions must be taken to ensure that the watertight integrity and strength of the bulkhead are maintained. With this in mind, sketch how the following pass through bulkheads:

(i) Main transmission shaft;

(ii) Electric cable.

Answer.

a) The purpose of a transverse watertight bulkhead is to divide the ship into watertight compartments, thus restrict the volume of water which may enter the ship due to damage to the shell plating. They also serve to separate different types of cargo. In the event of a fire, they greatly prevent the spread. They also increase the strength of the ship transversely.

Male and female halves of a gland around the cable are screwed together. Neoprene seal and felt washer are compressed to make a good seal.

(ii)

Over size hole in the bulkhead has a stuffing box fitted, fastened by studs to the bulkhead. Tightening of the bolts compresses hemp packing onto the shaft.  

May also use a mechanical seal as shown in the right hand sketch.