The automobile torpedo first came into use in the early seventies. It was the outcome of a series of experiments commenced in 1864 by Robert Whitehead, then superintendent of iron works at Fiume, Austria. This torpedo, known as the Whitehead or fish torpedo, claimed the following capabilities: (1) It could be adjusted to run at any depth from 5 to 15 feet when fired from either a submerged or surface tube, or from a surface detaching apparatus; (2) upon firing, it would make a straight run, pro vided a proper allowance was made for the deflection due to transverse currents; (3) it could be adjusted to stop at any distance up to its extreme range and after stopping to sink or float; (4) it could make a run of 1,000 yards at a speed of 15 or 16 knots, while 300 yards could be covered at a speed of 19 to 20 knots; (5) it could carry a warhead holding a charge of 33 pounds of guncotton, to explode upon contact. This torpedo whs propelled by a three-cylinder Brotherhood engine weighing 35 pounds, driving two propellers and developing 40 horse power. Eventually the Whitehead torpedo came to be used in the United States service, and later the Bliss-Leavitt torpedo was adopted. As heavier armor was added against torpedo attack a large gap developed which the Whitehead torpedo and its various lcindred rivals could not fill, and here it was that the genius of an American naval officer, Com mander Cleland Davis, placed the torpedo upon a new and more formidable footing. He aban doned the guncotton warhead, which was the accepted instrument of destruction since the inception of the Whitehead, and substituted a gun in its stead. If one will study carefully the photographs of either bursting submerged mines or exploding automobile torpedoes, the most impressive visual sign of the violence ex erted will be found in the great volumes of water blown upward. The water has yielded more than the steel structure attacked, and the major part of the energy designed to wredc has spent itself uselessly in blowing hundreds of tons of water into the air. Conunander Davis sought so to concentrate the powers of assault in his torpedo that but little of its force shcuild be dissipated in disturbing the surrounding water while the bulk of the energy of his weapon .should remain unimpaired and centred in piercing the enemy's defenses and penetrat ing to the very vitals of the object of attack. He did not discount in the slightest the truly remarkable developments which had taken place in the other departments of the automobile tor pedo. Increased range, higher speed' and more precise functioning all helped him toward his objective; but it is his invention which made this underwater projectile a graver menace to the largest of fighting craft. This torpedo car ries an eight-inch gun capable of expelling an eight-inch projectile with a muzzle velocity of 1,000 feet per second, which is quite enough to carry the projectile through a single plate of Krupp armor, something like four or five inches thick, where virtually in contact with the muz zle of the g.un — as would be the case with this torpedo. Ships are not protected under water with plating of these dimensions, and it would be a much easier task for the projectile to pass successively through a number of thinner plates even if their combined thickness were more than the limit set The projectile fired from this torpedo carries a bursting charge of high explosive of between 35 and 40 pounds. This charge is detonated by a delayed action fuse, which is designed to meet the maximum re quirements imposed by the best protected dread naughts built. When this weapon is launched upon its sinister errand the little propeller at the upper side of the torpedo's nose revolves and releases the tripping rod, so that the tor pedo can be discharged upon contact with its target. When the rod hits the obstruction it is driven backward and engages the trigger which first compresses a spring attached to the firing pin and then releases it so that the pin can strilce the gun primer, thus setting off the pro pelling charge of powder which drives the shell out of the gun. As soon as the projectile hits the outside plating of a ship's bottom the fuse in the base of the shell begins to function, being set to explode the charge in the shell so many hundredths of a second after impact.
The modern submarine torpedo varies in size according to the service for which it is intended and ranges from 14 inches in diameter and 15 feet in length to 21 inches in diameter and 21 feet in length, weighing from 1,000 to 2,600 pounds, the smaller type being used to sink tmprotected freight and passenger ships at short range. It is .capable of a speed of more than 30 miles per hour and when travel ing at normal speed possesses the great mo mentum of about 65,000 foot second pounds. Generally spealcing, the torpedo consists of the following parts: (1) The warhead, which con tains the high explosive charge, fired by an exploder upon striking the target, the charge ranging from 200 to 500 pounds, depending upon the type of torpedo; (2) The air flask, a specially constructed shell of steel, very strongly built to withstand a test pressure of 5,000 pounds to the square inch. This flask carries air at an initial pressure of 2,250 pounds per square inch, the air being used to operate all the mechanism of the torpedo in addition to the motive power; (3) The depth control mechanism, which permits the torpedo to be run at any desired depth under water, and which consists principally of a pendulum and a hydrostatic piston actuating horizontal rudders; (4) The gyroscopic steering gear. The gyro
static compass through the vertical rudders maintains the torpedo on a course parallel to that in which the torpedo began its run; (5) The engines. The air at the high pressure of 2,250 pounds per square inch first passes through a reducing valve which decreases its pressure to that required for use by the engine. This air is then heated by an alcohol flame, which also acts to produce steam of the water in the combustion flask, the air and steam mixing and passing to the engine. The engines are gen erally reciprocating, but in the Bliss-Leavitt and some other torpedoes are turbines driving two propellers.
Torpedoes are projected by means of special forms of tubes or guns. The tube is usually built into the hull of the submarine, in which case it is aimed by manoeuvring the boat. In the case of destroyers and battleships, the tor pedo may be projected from submerged tubes or from deck tubes. In general, torpedoes are projected from submerged tubes by compressed air and from deck tubes by a small charge of gunpowder. Submerged tubes on battleships, however, may be designed to use either powder or compressed air. When the torpedo is fired from a submerged tube the compressed air or the gas from the powder follows the torpedo out of the tube with a rush and causes an eruption on the surface of the sea, which is visible for a considerable distance. As a re sult of the warning given by this eruption, vessels have sometimes been able to escape the torpedoes by a quick manoeuvre. The modern torpedo is self-propelled, being driven through the water by its own compressed air motor, the air being supplied from a strongly-built reservoir within the body of the torpedo itself. Torpedoes directly operated by internal com bustion engines as motive power are not trust worthy. The range of a torpedo is approxi mately a mile, those designed for use on battle ships and destroyers being longer ranged than those for use on submarines. The great diffi culty in getting proper direction and sufficient motive power to give the required speed for a long duration of time renders the long range torpedo impracticable. The latest German tor pedo had a range of about 2,000 yards, as the compressed air storage reservoir was reduced in size in order to increase the charge of high explosive in the warhead. The charge was from 300 to 400 pounds. The depth at which a torpedo travels may be regulated to hit the Most vital part of the vessel, and that is usually about 10 feet below the surface. In case of torpedo attack against an armored ship the torpedo, to be dangerous, should strike be neath the armor belt, which usually extends about 10 feet below the water line. Torpedoes are usually provided with means to cut, more or less effectively, through nets placed in their paths. The detonation of the torpedo is ac complished through a mechanism placed within its warhead; and if the torpedo is checked in its forward motion the firing mechanism in stantly ignites the heavy charge of explosive contained within the warhead. It is not neces sary to strike a firing pin on the end of a tor pedo to detonate the charge. Many sugges tions have been submitted for a torpedo to be electrically propelled from a ship by means of a flexible cable connecting it with the ship. This was the first type of torpedo built, but was discarded for the present dirigible type, as the weight of cable difficulties in insulation, etc., render it of little practical value. The effectiveness of the Hammond radio-controlled torpedo ispromising. The Board of Ordnance and Fortifications recommended favorably to the Secretary of War as to the merits of this invention, and the Secretary recommended to Congress that this new type of weapon be in stalled in a few of the more important coast defenses.
When firing a torpedo at a moving target there are several important factors which the torpedoist must consider. These are the speed of the target, the course of the target and the speed of the torpedo itself, all of which factors must be known within limits in order to make effective hits. The various nations have their preference for torpedoes. The British use the Whitehead; the Germans, Schwartzkopf ; the French, Whitehead and Schneider; the Japan ese and Italians, the Whitehead. In the 'United States the Whitehead and Bliss-Leavitt tor Redoes are in general use. See NAVAL. MINES; SUBMARINE MINES; SUBMARINES.
Bibliography.— Fitzgerald, C. C. P.. (Sub marine Warfare' (London 1919) ; Talbot, F. A. A., (Submarines, their Mechanism and Oper ation) (London 1915) ; Donville-Fife, Charles W., 'Submarine (London 1914) ; Naval Annual, (British and Foreign Torpedo Boat Flotillas) (London 1912) ; Fulton, Robert, pedo, War and Submarine Explosions) (re print, New York 1914) ; Currey, E. H., The Menace of the Torpedo' (New York 1914) ; Bradford, R. B., (History of Torpedo Warfare' (Newport, R. I., 1882).