THE LAYIKG OF SUBMARINE CABLES. 141 



of the vessel at each position during the laying of the cable. 

 The true distances between each position are entered in the log 

 and added together as the ship proceeds, while the actual lengths 

 of cable paid out between each position are also recorded. 

 These respective distances and lengths so added together furnish 

 at once the amount of cable paid out up to any position and the 

 corresponding distance travelled by the ship, the difference be- 

 tween these distances giving the slack. The actual and per- 

 centage amount of slack paid out between positions is also 

 recorded, together with these figures for the whole cable. The 

 percentage of slack on cables laid in depths exceeding 1,500 

 fathoms may amount to 10 or 15 per cent., and in depths of 

 3,000 fathoms and upwards to as much as 20 per cent., but for 

 average depths the slack is about 6 per cent. The positions of 

 the various splices and the types of cable at the splices are also 

 recorded, and these records are altered according as new splices 

 and lengths of cable are added by subsequent repairs. 



Cable Laying Ships. — The very large vessels of gross tonnage 

 ranging from 3,000 to nearly 8,000 tons are owned by cable- 

 manufacturing companies, the great advantage of their size 

 being that when laying new cables they can take out up to 

 2,000 miles or more of mixed cable in one trip, and carry enough 

 coal for three or four months at sea. Considerable space and 

 accommodation on board is also required for the cable hut 

 material, stores, testing instruments, and staff destined for shore 

 work while the ship is laying cable. 



The largest cable-laying steamer afloat is the " Colonia," of 

 7,976 gross tonnage, owned by the Telegraph Construction and 

 Maintenance Company. This magnificent vessel, illustrated in 

 Fig. 67, has a carrying capacity in her four tanks of 4,000 

 nautical miles of cable, equal to double that of the " Great 

 Eastern." She was built by Messrs. Wigham, Richardson <fe Co, 

 of Newcastle-on-Tyne, launched in the spring of 1902, and is 

 500ft. long, 56ft. beam and 39ft. deep. She is 11,000 tons 

 gross register and will carry this dead weight at a speed of 11^ 

 knots. Her engines are 5,000 I.H.P., and on her trials she was 

 shown capable of a speed of 14i knots. On her first expedition 

 to lay the section of the Pacific cable between Vancouver and 

 Fanning Island she was loaded with 3,505 nautical miles of 

 cable, weighing 7,595 tons. 



