Engineering Wonders of the World
Volume III

THE LAYING OF SUBMARINE CABLES. 371 or four feet, in a straight line towards the ship, from the hut to low-water mark. There are several methods of landing the end of the cable. It will, however, be suffi- cient to describe that which is most favoured, where applicable, in modern Sh Prac^ce 5 for, besides being expeditious, it overcomes cer- tain difficulties and dangers surrounding the use of rafts, boats, etc. This plan is due to Mr. R. Kaye Gray, M.Inst.C.E., and consists of buoying the cable at every five or ten fathoms, as it is drawn shore wards, by means of empty casks, or preferably by temporarily inflated india-rubber balloon buoys, as shown in Fig. 25. In carrying out this method, the picking-up machine is usually turned to account to haul ashore the line with cable attached to it. The general scheme is illustrated in Fig. 26. Two light skeleton pulleys of large diameter (technically known as “ spider sheaves ”) are taken ashore, where they are firmly fixed just above high-water mark—one close to the mouth of the trench, and the other about 100 yards off along the beach in one direction or the other, according to the exact position Fig. 25.—gray’s method of landing cable BY BALLOON BUOYS. carried in a boat to the bows of the ship, where it is taken round the picking-up drum. The latter gear is then put into operation for hauling on to the line ; and thus the end of the cable, securely fastened to the rope, is grad- ually hauled ashore. As the cable leaves the stern of the ship, the balloon buoys are attached at the required intervals. Fig. 27 depicts the operation in a completed stage, the balloons being cut away after the cable has been brought to the testing-liut. By this method the average time taken for landing the cable is some four or five hours. The second shore end having been landed and the seaward end buoyed, the vessel with the main cable on board steams up to the buoy and proceeds to pick up the buoyed end. Having done so, a splice is effected between this cable end and that of the cable about Fig. 26.—HAULING CABLE ASHORE BY STEAM. of the ship. The hauling line brought ashore from the ship’s stern is now rove through the pulley nearest the trench ; and after being subsequently led through the other, it is to be laid towards the distant shore. On the completion of the splice, preparations are made for slipping the bight over the bows prel minary to paying out from the stern.