230 



SUBMABINE CABLE LAYING AND REPAIRING. 



If the circumference of the drum alone had been taken as 

 the length per turn, the result would have been short by 



Ml? = 628ft. 

 4 



After the cable passes the picking-up drum it is coiled into 

 one of the tanks on board. If the cable has to be coiled in 

 the fore tank, it is simply passed from the picking-up drum 

 direct through a ring in the cable hatch, known as the bell- 

 mouth, and down into the tank; but if it is to go in any tank 

 aft, a number of guide rollers are placed in convenient positions 



Fig. 135.— Bellmouth over Cable Tank, 



along the deck, over which the cable rides to the required tank. 

 The bellmouth (Fig. 135) is of use in both coiling in and pay- 

 ing out cable, in keeping it exactly over the middle of the tank. 

 It is cast in two halves, one half being bolted to the cross 

 timber, and the other hinged to it, so that it can be opened at 

 any time, when it is required to slip cable out. This is 

 necessary, for instance, during paying out, if it is required to 

 change over and pay out from another tank. 



Some ships carry two tanks forward of the engine-room and 

 one aft, while others carry four in all, the tanks varying in size 

 according to the tonnage of the ship. 



