WATCHING FOR SUBMARINES.

Oamaru Mail, Volume XL, Issue 12541, 12 May 1915, Page 3

WATCHING FOR SUBMARINES.

(Melbourne "Age" Correspondent.)

LONDON, March 19.

Numerous suggestions- for dealing with German submarines have reached the British Admiralty from patriotic persons who are anxious to help their country, but as most, of those who offer suggestions have never Men even the outside of a submarine, and know nothing- about naval matters, their ideas on the best way of destroying German submarines are not likeIv to prove of much use. For some years past the question of coping with enemy submarines has been receiving attention at the Admiralty. but before the outbreak of war the question was hampered bv the absence of exact knowledge of the nature of the. operations in which enemy submarines would engage. Since the outbreak of the war the question of destroying German submarines has occupied the best brains in the British navy, but up to the present no satisfactory solution of the problem has been found. But a considerable advance has been made in evolving methods of evading submarine attack by torpedo. In this direction the British navy has done much since I September 22. when three British cruisi, crs of 12,000 tons, Aboukir, Cressy, and ' Hogue, were torpedoed by a- single German submarine in an hour. The passage of British troopships across the Channel day after day, and the transport of army stores without an accident, is a testimony to the fact that the, ships of the British navv which protect the troopships and transports, have learnt, not only how to evade submarine attack, but how to keep the submarines off from attacking the ships under their protection. After the conclusion of the war, naval architects will doubtless give attention to designing a special type of vessel for operation against submarines, but up to the present it would seem that the ancient manoeuvre of ramming is the most effective way of dealing How many 'submarines G«pMy has lost since the outbreak of warns not known. That, is a matter oil which the German Admiralty gives no information. It may be assumed - .' since disaster to. submarines Was not an unusual feature.of navy manoeuvres in times of peace, that accidental-1 disaster has overtaken some of. the German submarines while operating in Bri : ' tish waters far from their bases. But of I the four German submarines known to have been sunk by British war ships all were, rammed. The hull of the submarine is 'thin in order to give the" vessel buoyancy; and therefore. she- is " particularly vulnerable to impact. ■ . The circumstances- in "liioli German submarines have been rammed by British destroyers have not -been disclosed, because "the information might prove of value to the .enemy, but in -connection with the submarine' "blockade" of GreatBritain, Count Reventlow, well known in Germany as a naval critic, explains in the •'Deutsche Tageszeitung" how British destrovers lie in wait for German ■ submarines.. Masses of light vessels, especially - destroyers, have-been gathered by the- - British Admiralty in the Irish Sea and the Channel," he states, "but the torpedo boat, is recognised ...as the. submarine's worst- enemy. They' can be used .in all waters. There are large numbers of them available; they are-"exceedingly mobile, and can rise from passivity to. maximum speed at a moment's notice. They carry guns with very rapid fire, and capable of mortally injuring at a considerable distance any submarine showing itself on the surface. " We have to picture a submarine hunt by destroyers somewhat thus: These light craft either cruise-at a definite distance from one another, or they lie stiil, preserving the same distances. Each of ■ them, however, exercises all the time an extremely careful control of that section of the surface of the sea appointed for it. The moment that the periscope of a I submarine, or perhaps even the conning I tower, appears above the surface it is I fired at, or else a torpedo boat- or destroy- ' er which happens to' be favourably placed for. the manoeuvre leaps at top speed towards'the point where the submarine has appeared, its object being to ram the submarine before the adversary has seen it or has had time to dive deep enough to enabl-e the enemy's vessel to glide over' it. Even if the attempt to ram is? a failure the enemy's destroyers only increase their watchfulness, on the ground that.the. subI marine must- sooner or later come some- ! where to the surface and get its bearings, j That is particularly the case 'in waters I where theie is a great deal of merchant shipping.'?

Count Reventlow declares that owing to , the narrow range of vision of the sub- | marine through its periscope, or even from the conning tower, compared to the range of its own' visibility from the bridge of a destroyer, it is quite possible for a destroyer to perceive it and reach the spot travelling at full speed before the submarine hi turn can sight the destroyer and dive to safety. The submarine- is propelled on the surface by oil engines, and under water by electric engines, the electric batteries being stored by the operation of the oil engines. She has therefore to run on the surface in order to enable her to fill her electric, batteries, so as to be able to continue her voyage in a submerged condition. The "average range of a submarine (decided by the- amount of' oil fuel she can carry) is about 2000 miles on the- surface, and in covering that 2000 miles she stores up enough electric power to take her about 200 miles in a submerged condition. The submarine is in realitv only a submersible, and has to spend a great deal of her time on the surface. There is no doubt that, the German submarines while operating in British waters fill their electric accumulators by running on the surface at night. But the fact that the submarine must spend a great deal of time on the surface and that after being submerged she has to come to the surface for air for her crew and to get her hearings, make the vessel far more vulnerable to attack than' is generally "supposed. The comparative immunity from destruction by torpedo attack which the torpedo boat and the torpedo boat destroyer enjoy is due to the small size, light draught and great speed of these craft. Even the large British destroyers are of little more than 1000 tons displacement, and they have a speed of 34 knots. The slowest destroyers in the British navv have a designed speed of 29 knots, which was exceeded when their speed Was officially tested. 'The torpedo is. not a reliable weapon except at close range, and therefore submarines have little % or no prospect of Jutting a small fast vessel of light draught like a torpedo boat or a torpedo boat destroyer.