HOW WE DESTROY "U" BOATS.

Pukekohe & Waiuku Times, Volume 5, Issue 163, 7 April 1916, Page 2 (Supplement)

HOW WE DESTROY "U" BOATS.

SOME STARTLING REVELATION'S REGARDING THE METHODS ADOPTED BY THE BRITISH NAVY TO KEEP THE SEAS CLEAR OF GERMAN SUBMARINES. By REGINALD L. FOSTER (of the "New Y'ork World.") When the war began on August Ist, official figures were at hand as to the number of German submarines, ihey totalled just forty-five twenty-seven submarines built and' commissioned, and eighteen budding. To turn out a submarine in time of peace takes two years. Therefore, it might lie presumed, no more could be finished up to the present date. But more were finished. How? Because the intensive Germans began specialising on submarines and before long were finishing them in nine months' time, scores of them—perhaps two or three a week. This was achieved by working in three-hour shifts of fresh men, twentyfour hours a day . But there is something else needful liesides the submarine? to make this kind of naval warfare underseas successful, and that is a crew for her. The submarine crew is the highest type of specialised lighter that this war has developed. More work is required to contrive a crew for a submarine thai to build the submarine itself. And though Germany wont admit it, the loss of fifty odd submarines' crews is worse blow than the loss of the boatsAnd, if tlie truth must be told, tin surviving crews are in a panic. When they leave home waters they hardly expect to come back, iliess dreadful days. The crew of a German battleship or a cruiser sunk in a fair light gets all the iionousr of war, ani is rescued to the last man possible. Many are the methods of "getting the submarines of which the chief aro four. Nets, torpedo-obats, "chasers" and "fate" trawlers. Minor ways of submarine-getting are mines, "gumming-' the eye of the periscope with oil, aeroplanes and microphones, which are siid to detect a submarine seventy-five lirles away. NETS HUNG FROM GLASS GLOBES.

The netting most often used is mad** of stout galvanised wire, with a 15-fL mesh. This is cut in lengths of i7oft., with a depth of 45 ft. On top of this great net are lashed immense blocks of wood for buoys. Two oil-burning destroyers now take the netting and hang it between them, as deep down in tli? water as it will reach, and are resdy to go submarine-hunting. The range of a submarine's peris-ope is little over a mile in any sort oi i ea Vessels that are belching smoky and lie on the horizon may be picked i:p tor three or four miles, but no mo.*\ A periscope can be seen.as far as : : tees of watchful eyes are on the job. The twin net-bearing cost rovers spy a periscope. They chart the submarine's direction and speed (out of range) to a point directly ahead. Now the lashings are cut away and lie net left in the German's path, while tue destroyers sneak out of eye-shot. Three times out of four it is declared, the submarine gets tangled in the net. Her delicate machinery is disarranged and her balance upset. She may turn turtle. Now the rest Is easy. It has only taken one shot from the threeinch rapid-fire gun. Eight or ten submarines have escaped accidentally by changing tlu>ir courses after the nets have been let go. But never once has a periscope sighted l a destroyer, which lies low on the water and lets out no smudge of smoke from oil-burners.

Other nets are hung from huge hoilow glass balls—glass so that the periscope cannot pick them out against the surface of the sea. These nets nave regular tenders in the shape of torpedo boats, which go their rounds just as a fisherman goes his rounds, looking for fish caught by their gills. 'I best cover the English Channe 1 , and are floating m many places in the North Sea where there is any likelihood of a submarine being busy. \\ hen a glass ball disappears there is a torpedo boat on the job in a jiffy, waiting for the Mctim to come to the surface — - il ever she can. The king of our sailors' outdoor sports is "chasing" submarines. The crews of the chasers are now experts at the name. GUMMING A SUBMARINE'S EYE.' Now, every submarine makes what the experts call a "surface wave. ' Even at (30 feet deep she leaves a distinct path, and 61) feet is pretty deep tor any submarine to venture. Bes.des this plain track, there are also innumerable bubbles of air and globules of oil, continually escaping to the surface, plain indication, to the observant eye, of a submarine hovering below. All right—the "chaser" catches the " surface wave." This spells the end /or the submarine, unless a storm comes up or iog falls. For it is merely the business of the speedier motor-boat to keep above the wave, and the tinii lias got to come when the submarine must bob up to get her bearings or to see what she can see. it is all over m ten seconds.

Aeroplanes have a winning way witii them, too. it is their custom to fly a* slowly as possible over the shallow waters around the British coast and spy out (Jennan submarines resting 011 tne bottom, a regular tr.ck of theirs. And iicre the aeroplane has shown its great usefulness. Tec shallow water liiat surrounds the coastline* makes jt possible lor the aviator to spy out uie submarine as she lies, blind and immobile, on the bottom, even KJU teet d ep . lie notes the position and notifies the nearest patrol boat, which siiecds to the spot. Now it is only a case o! awiting lor the snbuiarme to rise. You know the rest if you have read tiiu> tar. .Mines are anchored from the bottom t about the cruising distance of a submarine from tiie Mirface. One hit is enough. .Nothing ever comes up to r-M the tale. Months alter, perhaps, in Oermany another submarine is listed as missing—yes. mi>sing until the sea shall give up its dead. " (Summing the eye" is another sport. A tanker merely steams around in c on--1 eiitric circles at a -pot on the sea fre-i|i;ent.-d by S'.ibuiarin'S, and the oil go's en the glass of the p< nscope end shuts out the view. Then the boat must open up and let a man out on do- k to dean the p- riseope. It' a "<-!ia»er" happens to be around the submarine doesn't Let a chanee to submerge o! !- own accord.