108 SUBMARINE CABLE LAYING AND REPAIRING. 



12 working hours, or double that length per day of 24 hours. 

 It takes a week or two to prepare and test sufiBcient core to 

 start ten machines, and after that the core can be turned out at 

 the rate necessary to keep all machines going. 



It is usual to distinguish by a section number the cable 

 manufactured by each machine and to pass these into separate 

 tanks, from which they are afterwards drawn out and passed 

 over to the cable ship in the lengths and in the order required 

 for laying. The various lengths of each type required are 

 calculated from the best knowledge of the curvature of the 

 ocean bed that can be obtained, allowing a little over for con- 

 tingencies, but it is rare that the spare cable left after comple- 

 tion of the laying exceeds 5 per cent, of the length laid, and it 

 is often possible to estimate the true length to within 2 per 

 cent. 



