THE CABLE SHIP ON KEPAIRS. 



239 



space taken up by feather-edge. Also the cone is reckoned 

 as a straight cylinder of diameter equal to the mean diameter 

 of the cone, but this means that in the lower part of the tank 

 the actual coiled length is rather less than the calculated length, 

 while at the upper part of the tank the actual is rather more 

 than the calculated length. It will therefore be seen that the 

 figures are only approximate, but, nevertheless, with these 

 limitations they are very useful when a load of cable is to be 

 coiled in tanks or for the purpose of checking the lengths 

 already in tank. 



Fig. 137 shows the position of cable-tank in the ship, built 

 upon the water-ballast tanks, and Fig. 138 a section through 



Fig. 138.— Capacity of Tank. 



the tank, showing the cone in the centre. The dimensions 

 given are of No. 2 tank on the cable-ship " Electra " (Eastern 

 Telegraph Company). The tank is 25 fb. diameter and 12 ft. 

 deep, so would carry (by the table given above) 14-7 nauts of 

 Type D deep-sea cable per foot height ; that is, 14*7 x 10 = 147 

 nauts loaded to 10 ft. height. The two aft tanks in this vessel 

 are 17 ft. diameter by 7 ft. deep. Eeckoning the cone as 4 ft. 

 mean diameter throughout, the net coiling space in each of 

 these tanks is (17' - 4') -7854 = 215 c. ft. per foot height. 



Loaded, say, with Ty^e B, the length of cable per foot height 

 would be 



= 4"7 nauts, 



46 ' 



