NAVY’S USEFUL WORK

Dominion, Volume 30, Issue 46, 18 November 1936, Page 15

NAVY’S USEFUL WORK

Cook Strait Cable Survey The New Zealand Division of tho Royal Navy is rendering a valuable service to the engineering branch of rtie post office in connection with its preparations for laying a new singlecore high-frequency telephone cable across Cook Strait. The route from Lyall Bay in the North Island to the mouth of Blind River, Marlborough, is •10 sea miles long, and it is of the greatest importance that the department should be in possession of detailed information regarding the nature of the bottom so as to secure the best possible bed for the cable. The post office engineers have collected a good deal of data from time to time while laying other cables and during repairing operations, and this has enabled them to select what appears to be a very suitable route along which the greatest depth is 1200 feet, this being found approximately half-way across Cook Strait. There are two “deeps” on the route,

and it is important to ascertain the exact conditions in their vicinity so as to avoid abrupt angles and unsupported lengths in the cable. The nature of the bottom is generally sandy, except for 10 miles out from Lyall Bay where patches of rock render it necessary to exercise great care in selecting a safe bed for the cable. Marine surveys and the taking of soundings constitute an important part of naval training, and the Wakakura’s personnel is thoroughly experienced in this work, the ship being fitted with a special sounding boom and sounding machines. The Wakakura is now engaged taking a line of soundings at half-mile intervals along the proposed cable route and will also sound similarly on two parallel lines half a mile north and south, as well as closely investigating the conditions 10 miles out from Lyall Bay. Samples of the bottom will be obtained at each sounding. The work is extensive, for over 200 soundings and samples have to be secured, and it is expected that at least 14 working days will be needed before the Wakakura’s useful task is completed.