THE SMALL FIGHTING CRAFT

Dominion, Volume 8, Issue 2305, 12 November 1914, Page 6

THE SMALL FIGHTING CRAFT

THE TORPEDO-BOAT AND ITS KIND

VESSELS THAT TAKE RISKS

There is a good deal of popular misconception ana contusion on tlie subject of torpedo-boats, torpedo-gunboats, and "destroyers." It is not unnatural, for it would puzzle the greatest expert to give a concise definition of each which would justify its distinctive name. A torpedo-boat is simply a small vessel — say 280 to 300 tons displacement—whose function is to carry a supply of torpedoes and the necessary apparatus for launching them against tne. enemy's battleships and cruisers when she can get near enough to do so. To tho torpedo-boat is given a very high speed, say 26 knots, and is kept of small dimonsions. These requirements preclude the carrying of heavy guns or armour. Consequently .the torpedoboat's work is tremendously dangerous. Of course, a cruiser's armour would not stand up against the onslaught of a battleship's heavy guns, but a cruiser is not asked to engage a battleship, and a torpedo-boat is. :

The torpedo-gunboat as a distinct type is obsolete. Those of 1894 were vessels of over 1000 tons, with a speed of 10 knots. Their-guns were two 4.7inch and four 6-pounders; but their chief weapons were five tubes for discharging torpedoes. Their supposed "superiority to torpedo-boats proper lay in their greater sea-keeping capacity and their comparatively large guns. The "Destroyer." The popularly so-called "destroyer" is properly called torpedo-boat destroyer, and when given its proper name its functions are less likely to be misunderstood. It was originally intended to overtake and destroy an enemy's torpedoboats without at the same time being so large or so costly that its own loss would be of great importance. It first came into existence in our navy some twenty or more years ago, when Franco, whose naval policy and ours were at that time mutually .. responsive, was piling up a .formidable flotilla of excellent sea-going torpedo-boatst—"torpil-leurs de haute mer"—and our own Admiralty had somewhat extreme views of the future'of torpedo warfare. History has.merely repeated itself liere, for tho imminent passing of. the battleship type in face of the torpedo was then discussed as* seriously as it was the other day in face of the I'submarine," which is ■ simply the handy name for. a submarine or submersilo torpedo-boat. The "destroyer,", therefore, came'into existenca to destroy ordinary torpedo-boats by gunfire and battleships by torpedoes. 'Originally a boat of 180 tons or so and of 22 knots speed, it-rose to 280 tons and 30 knots speed. Then the disaster to the Cobra, which broke her back when driving into a North Sea gale, caused a reaction, and the next destroyers were boats of about 500 tons.and 25 knots. No such change was made by other Powers, and the Admiralty very scon began tp put the speed-up again, but without sacrificing' seaworthiness. There probably is no real reason why .all'small vessels mainly intended for the carrying and launching of torpedoes should not simply bo called torpedoboats, except, perhaps, that it is politic to please the taxpayer by giving novel and suggestive names to the vessels : which he has to pay for. At present the two classes of torpedo craft recognised are "torpedo-boat destroyers" and "first-class torpedo-boats."

The Tornedo. ( . The _ torpedo itself has been the object of ,more invention and improvement than almost any singlo fighting instrument, except perhaps tho submarine. It may he described as an automobile mine, put into the water from a _ ship of some kind and left to propel itself against an enemy's ship, where the mere act of touching causes it to explode. As first invented by Whitehead, about 1868, its speed was not more than 9 or 10 knots, and sometimes less, its extreme range only some 200 yards, and its charge, about 301b. explosive. The immediate need, as shown when the torpedo was firstused in war—that between Chile and Peru in 1877 was speed, and this had risen by 1899 to something over '20 knots. That meant a very much better chance of hitting a moving target from a position which is itself moving. The next type of torpedo, brought out in about 1892, had'a-speed of about 25 knots, carried a charge of over 2001b. explosive, and had a range of over 2000 yards. This, gave a calibre of nearly 18in., as against the originalcalibre of only 13in., and the total weight of tho torpedo was beginning to Be a limiting factor to further progress. A torpedo must be capablo of easy and safe handling in a rolling vessel.

The present-day torpedo has a speed of nearly 50 knots, a range. of 6000 yards, a calibre of 21in., weighs some 20001b., and costs about £500. This very large price to be paid for one shot —and in a running action between torpedo-boats and battleships not more' .than one-third of the torpedoes' fired' are expected to hit—is a sure indication of the torpedo's deadliness when it does hit its mark, and of the amount of precise mechanism that is crowded into' it to this end. Correctly aimed, it is sure to be effective', except in very unfavourable circumstances. Wheu it does reach the skin of a ship the destruction, great as it is, is very largely of an indirect kind. The breach made' directly by

tho explosion is usually small, compared with tho final hydraulic damage done by the return of the water displaced by the explosion. In the RussoJapanese War some of the breaches made by torpedoes affected an area of twenty square yards. Tprnedo Mechanism. The special /jiechanism peculiar to torpedoes, -apart from the gyrbstatio control of the vertical, rudders with which most people are familiar, are the submersion regulator, the speed regulator, and the air-heater. Otherwiso the torpedo is simply a tiny submarine boat driven by ud air engine. The submersion regulator is generally set so that the torpedo travels at a depth of about 10 feet below the surface, the control being hydrq-static pressure acting through an elastic membrane • in contact with the sea and connected through suitable multiplying devices to tho horizontal rudders. In order to aim correctly to hit a moving vessel the speed of the torpedo must be known, and therefore must, he constant, which calls for a speed regulator to keep the air pressure constant at the engine though diminishing in the reservoir. The air also is heated by the burning of alcohol, petrol, or thermite, initiated by tho automatio deflagration of a cartridge when the torpedo begins its journey, to a temperature of 300 degrees; and it is the consequent expansion which accounts for. the presentday high speeds and long ranges.