OUR ANTI-TORPEDO DEFENCES.

Oamaru Mail, Volume XLVII, Issue 13084, 21 February 1917, Page 2

OUR ANTI-TORPEDO DEFENCES.

.NEW ASPECT OF THE BOOMACKOSS THE TIDEWAY.

One lesson of the war afloat is' the importance, of anti-torpedo defence of anchorages. The open sea-way commanded! by batteries is no longer safe for "resting" ships, and the expert contention against our east coast- harbors —that they were not torpedo proofseemed at "one time to hint, of a great national danger. The ingenious devilry of the- minefield' is a great defensive power, yet the ancient "method of placing a boom across th'e! tide-way has come into renown. In the days of theGreeks, the.entrance to any important harbor was closed at night by a chain drawn across the piers. This prevented both mutiny and piracy, evils to which the old-time shipping trade, was peculiarly exposed. Since then the. boom has been in and out of vogue, but never entirely discredited. In our own naval history there have been many exciting incidents concerning the boom as a defence. When cannon came into use, heavier pieces could be mounted ashore than oh decks, and the well-fortified port could' almost defy liiid'ers. But hy-aml-by new ships were planned to carry heavy metal and so powerful that they could scarcely besunk by direct battery. fire. The: redoubtable Blake, indeed, thought so little of the shore forts of his day that he. could order a. ship to engage and silence one by muzzle-to-muzzle cannonade. IN THE MEDWAY.

In 16G7, during the disastrous war witli the Dutch, the Medway'had to lip defended! by sunken shipping and a heavy ehaiii across the'only--" channel. Do Ruyter was baffled, but £. frigate of his 'command boarded l a guard-ship and landed a party.which either cast off or broke the chain, and allowed the Dutch to come up on the next tide to burn Chatham Dockyard. Twenty-two years later the Franco-Irish troops put •i boom across the Foyle. to prevent assistance coming to besieged Londonderry. This boom was made of "large pieces of firwood! strongly bound together, more than a quarter of a mile in length and firmly fastened 1 to both =hores by a cable a foot thick." The bursting"of this obstruction by the food ship Mountjoy, under cover of the. guns of the Dartmouth, was dramatic in the. extreme. , In 1702, Sir George Rooke attacked Vigo Bay. and found, it defended- -by a verv strong boom, mad© up of masts, viirds, cables, top-chains, and casks, about three: yards in circumference and kept steadv'by anchors at both ends. This obstruction was three-quarters of a mile long, and was raked by- seventy gun ships "moored at each end. besides the batteries on the hill above. Sir George's squadron advanced, before the wind and und«r a press of canvas, and the leading ship, . the Torbay. eighty guns, broke through with a tremendous' crash. In what -manner the no\r British booms are built, manned, and armed it would be unwise to specify. One knows ihev are quite different from the floats ing' defence swung across Portsmouth Harbor some years ago, and charged bv a destrover at full speed. Though the hour fixed for the experiment was early, a good many spectators witnessed the destroyer's swift, rac? inward, saw ship and boom quiver, and in a genera] wav noted the result. A similar experiment ivas tried at Bantry Bay, One wonders what- thickness of chain and timber would be needed to fit-op a Tiger if Sir David Beatty decided that she should open out her full thirtyone knots and hurl herself at some obstruction floating in the channel behind Heligoland. "HARD-LIVING" MONEY.

The men in charge of our harbor boom and torpedo defences are, according to n. recent Admiralty memorandum, to qualify for "hard - living money," a grant ranging from 6d per day, 'which has always been allowed' to destroyer crews in consideration of the hard living and exposure •which came their way in doing difficult service. Like that of the destroyer men. the money will he more than well earned. One can "imagine- many .a winter evening -when such guardianship, even atextra. pay, will be quite unattractive. The outside edge of a great naval harbor is usually t-hoi haunt of vicious tidal rips and cross-currents, and the tiny craft to which the service is likely to be given may have strenuous times, indeed'. Navigation in such places may lie a serious difficulty. A discovery anywhere, near the. bar of a. naval port means for the enemy a concentration of powerful searchliglits and a Well-directed' hurricane of flying steel. A hundred attackers could not escape their doom in such a fusillade.

Thirty years ago one saw the boom towed out on solemn occasions, but the practice of the new obstructions is constant, and not at the whim of the adimiral or any influential' visitor. The new iv;gulations as to mercantile and other shipping entering port at statedl periods have made the -working of a boom or floating barricade much different from what it was in time of peace. W. T. P.