MARVELS OF THE DEEP SEA CABLE

Auckland Star, Volume LXX, Issue 177, 29 July 1939, Page 5 (Supplement)

MARVELS OF THE DEEP SEA CABLE

Fwmamrs mam being ploughed in the ocean bed Cor cables to rest in. With moot of us still the marvel remains of the deep-sea cables sunk in the darkness, along with night and day "the words of men flicker and flutter and beat." They are precious things, strong as banded steel yet fragile in the delicacy of their working, and consequently needing the utmost care for their protection. Whore these mighty links between Britain and America cross the fishing grounds they are being protected by being sunk into trenches. For the greater part of the 3000 miles which they reach across they lie on the deep-eef ooze, unknown and unseen, theft** only visitants the tiny shells which endlessly fall about them and encrust them. There, more than a mile below the waves, they are secure against any damage except that of a marine earthquake. It is otherwise in the shallower waters of the fishing grounds, where the depth varies between 500 feet and 2700 feet. There the cable is not immune from injury. The trawling gear of the fishing fleets may entangle it, and in an hour may inflict damage which it takes days or weeks and much expense to repair. The romance of the deep-sea cables begins with these trenches. One of the cable ships (which can itself carry 700 irtiles of cable) is the ploughman. It does not speed the plough from behind, but draps it after it as it slowly steams along. From the ship a steel-linked chain, which may be paid out to 4200 feet, stretches to the plough, which is like

no plough ever seen on land, but ia 20 feet long, weighs nine tons, and ha« a cutting edge of stellite, harder than the toughest steel. The ship move* forward with cable and with plough and steel-1 inked chain. The depth and smoothness of the bottom are signalled to the captain on the bridge, along another communicating thin cable, and the same tell-tale cable informs him what progress the plough ia making, and whether and how the cable attached is being well and truly laid in the furrow the plough ia digging. None can aee. No diver could reach the plough as it cut* its way inexorably on; but the captain of the cable ship knows. One furrow has been cut a hundred miles off the Irish coast, and another off the west coast of Cornwall. The ocean bed plough makes iU lonely furrow for the use of men and to protect their handiwork. It is the outcome of long continued experiment. It wae necessary to construct a plough capable not merely of making a deep furrow, but of feeding the cable (which was being handled at the same time) into the trench. For this work the chain draprginfr the plough had to be both strong and flexible. It had to stand a pull equal to 43,000 pounds, or nearly 20 tone. The chain is made up of 12.800 link*, each weighing three pounds, and its manufacture was a difficult problem, because its whole length of 4200 feet had to be forged in one piece. Engineers will marvel at the ingenuity of thus invention, which will make the deep-sea cables safe at their weakest point. But the marvel beyond it ie of the silent plough pushing forward in the depth* of the sea ! at man's command.