THE CABLE SHiP ON REPAIKS. 241 



very readily calculated. Taking, for example, the above tank 

 (Fig. 138), there will be 140 turns of cable to the topmost flake, 

 since the width across from coue to outside of tank at 8tc. 

 height is 10ft. Gin. (or 126in.), and the cable is 'Qin. diameter: 

 hence 



1^^X1Q = 140 turn.. 

 9 



Further, the mean length per turn is found by multiplying 



the mean diameter of the flake by 3'1416, and the mean 



diameter is found by taking half the sum of the diameters of 



cone and tank at that height. Thus, the flake, at the height 



of 8ft. in the tank, has a mean diameter of 



i±^ = 14-5ft.. 



2 



and this, multiplied by 3-1416, gives 45-55ft. as the mean 

 length of cable per turn. Hence, the length of cable per flake is 



140x45-55 = 6,377ft., or 1-047 naut. 



The mean diameter increases slightly down to the lowest flake, 

 as shown by the lines D D, on account of the cone ; hence, the 

 caean length per turn increases, but, at the same time, the 

 number of turns per flake decreases more rapidly, and the 

 length of cable per flake is consequently less, the lowest flake, 

 by a similar calculation, containing 1-013 naut. 



Picking-up Gear. — We should now, as the ship is supposed to 

 be nearly up to the fault, spend the rest of our time on deck. 

 Here the cable is still coming inboard, and our attention may 

 be given for a few moments to the steam picking-up gear. This 

 is fixed forward of the bridge, the bedplate being bolted down 

 to the main deck. Space is a consideration on board, and the 

 gear is usually of very compact design, so as to take up as little 

 room as possible. The illustration in Fig. 140 is of the picking- 

 up gear on board the cable-ship "Dacia," belonging to the 

 India Eubber, Gutta Percha, and Telegraph Works Company, 

 Silvertown. 



This perspective view takes in all the machinery as far as 

 the bows, and the path of the cable from the bows to the tank 

 can be well traced. The cable comes in over the bow sheave 

 B S, then passes over the guide sheave G S, under dynamometer 



