Strait Cable Ship Ready For Trial

Press, Volume CIII, Issue 30578, 22 October 1964, Page 3

Strait Cable Ship Ready For Trial

(From Our Own Reporter) WELLINGTON, Oct. 21. The converted freighter, Photinia, is almost ready to lay the Cook Strait cables. Decks crowded with cable wheels, gantries, conveyors and instruments, it was on show before it begins exercises in the strait with familiarisation runs over the 25-mile shore ends of the cables. After these trials, laying will begin when the weather favours this precise, carefully planned task. No existing cable ship can handle the five-inch, 901 b-a-yard yard cables that will cross the strait When the Photinia was built in 1961 it was strengthened with this kind of work in view. Five hundred tons of steelwork and extra engines developing 1500 horsepower to

drive the cable-winding machinery have been added, tested in Scottish waters with a sample cable, and re-erect-ed for the laying operation. To house the additional crew, 10 huts, each with air conditioning, have been set up in the sifter hold like a four-storey block of flats. These messes are equipped with piped beer—free to the crew, a policy which the contractors found actually cut down consumption by eliminating rounds of drinks. The three cables, each 25J miles long and weighing 1500 tons lie coiled immaculately by hand in three of the spacious holds that were designed for bulk cargoes. Above each is a massive gantry and 16-ft diameter wheel over which the cable will be wound through roller conveyors to a giant capstan near the bow. From there, the cable will slip over the bow wheel and through a bell-shaped funnel into the strait. Supervising this final part of the operation will be an engineer from Devon, Mr

Fred Channon, watching the control panel that registers the speed and tension of the cable. As the ship steams forward at three to four knots and the cable plays out, the operation will be monitored in a recording room amidships. There, one of the contractors’ mathematicians, Mr M. J. Sayers, will check the speed and tension of the cable against a plot calculated on a computer. It took three weeks to combine information on the cable’s weight and diameter, the speed of the ship, the profile of the seabed along the route, and the tension required on the cable when it rests on the bottom. Through the elaborate communications system that sprouts loudspeakers and microphones all over the ship, advice will be issued to the engine-room, the holds, the deck machinery operators and the cable-laying controller at the bow. With so much gear on the ship, there seems little room for the 100 members of the

crew to carry out a job that will demand the utmost concentration. Forty seamen run the ship, 35 of the contractors’ men and engineers have been joined by 20 cable hands of the New Zealand Post Office. “It is not a dangerous job,” said Mr J. N. Gobson, installation manager for 8.1.C.C., “providing everyone can give it their undivided attention.” It will take three runs across the strait to lay the cables. Two will provide the electrical circuit; the third will be a spare. Steaming at three to four knots each run should last less than 24 hours. Favourable sea and wind will be chosen but the highsensitivity. automatic track plotter will determine the shin’s position within inches. The bow propeller will help adjust the course. A 12ft by sft tunnel was built through the bow to accommodate it for this job. In one hold lies 100 yards of cable for the familiarisation trials preceding the main laying runs. The Photinia also carries five miles of spare cable. Laying will begin at the northern terminal, Oteranga

Bay, where the shelter is least along the course. Thus, even if the weather deteriorates, the job can continue on a progressively more favourable course. Three fixed transmitting stations ashore at Oteranga Bay, Fighting Bay and Cloudy Bay, will work with the track plotter in the wheel house. A chart on the plotter has the course marked upon it and the helmsman will keep the stylus of the plotter on this route. The landing of one shore end at Oteranga Bay will take an estimated six hours. The trin across the strait will take about six hours. Another six hours, say the engineers, will be needed to land the finishing end. Then the whole operation will be repeated with the second and third cables. They will lie 1000 yards apart except at the terminals. As soon as the ends have been landed they will be jointed to the shore ends already laid. When the cables have been tested for gas pressure (6001 b for four days), and with a 30-minute 520,000 volt electrical charge, they will be ready for service.