In the early days of the submarine it was believed that she might be sunk by using spar torpedoes fixed in swift boats, which would bear down upon the submarine as she submerged and explode the charge against her hull. But it soon occurred to seamen that if a swift vessel, destroyer or other, could run down a submarine she might more easily sink her by the impact of her sharp stem or a special keel. This method has been practised in the war, and by this means a number of enemy submarines have been dispatched to Davy Jones’s locker. There was an early case in which a certain destroyer, going at high speed, actually impaled a German submarine on her stem, and carried her onward, so injured that she sank. Another early case was that of the German submarine rammed and sent to the bottom off Beachy Head on March 28th, 1915, by the _Thordis_, commanded by that plucky skipper, Captain Bell, who set an example to many.
Another plan was to use suitable vessels in pairs, each pair dragging a cable connecting them, from which hung, on short lines, small mines to be electrically exploded when a submerged obstruction, probably a periscope or conning-tower, put a tension upon the connecting cable. The disadvantage of this system was that the entrapping vessels could not travel swiftly without bringing the cable near to the surface, and the chance of a submarine fouling the cable was remote. Yet it may be conjectured that the features of this system may have furnished the germ of procedures now in use. Capture or sinking by the use of nets was also an early idea, probably suggested by the nets used by big ships at anchor for protection against torpedoes, and Admiral Sir Arthur Wilson devised a large steel net for the purpose. Possibly this method, too, has developed into the nets employed in dealing with enemy submarines at the present time. But submarines were continually increasing in strength of structure, speed, and handiness, so that new systems were necessary and have developed with the requirements.
What the actual methods employed by the Navy are cannot be explained. When Mr. Frederick Palmer, the American writer, visited the Grand Fleet he asked how the thing was done, and officers said: “Sometimes by ramming; sometimes by gunfire; sometimes by explosives; and in many other ways which we do not tell.” M. Joseph Reinach also visited the Fleet, and said in the _Figaro_ that the submarine was pursued “by net, gun, explosive bomb, and other means.” Squadron-Commander Bigsworth on August 26th, 1915, destroyed a submarine off Ostend by dropping bombs upon her from his aeroplane, and there have been several other episodes of the same kind. When the first American transports were attacked in the Atlantic, bombs fitted with a short-time fuse were employed which burst at a determined depth below the surface of the sea.