If they could sink two battleships in three days, why didn’t the German undersea boats sink a dozen or so more and raise the siege of the Dardanelles? Enver Pasha, the Turkish minister of war, declared that “the presence of the submarines destroyed all hopes of Russia’s ever effectively landing troops on the coast north of Constantinople.” Then why did they permit the landing of British, Australian, New Zealand, and French troops on the Gallipoli Peninsula and the plains of ancient Troy? It was not until August, 1915, that the transport Royal Edward was sunk in the Mediterranean by an Austrian submarine. Perhaps before this war is over some British transport may be torpedoed in the North Sea or the English Channel, but for more than a year and a half since its outbreak, troop-ships and store-ships have been crossing to France as if there were not a hostile “U-boat” in the world. Equally mysterious has been the immunity of the light-draft monitors and obsolescent gunboats off the Flemish coast, where their heavy guns did so much to check the first German drive on Calais, and have harassed the invaders’ right flank ever since. Many of these are mere floating platforms for one or two modern guns, all are slow-steaming, and they are not always in water too shallow for an undersea boat to swim in, yet none have been sunk by a submarine since the loss of the Hermes, in the autumn of 1914. Zeebrugge, the Belgian port that has been made the headquarters for German submarines in the North Sea, has been several times bombarded by the British fleet and, according to reports from Amsterdam, half-built submarines on the shore there have been destroyed by shell-fire. Why did the completed undersea boats in the harbor fail to come out and torpedo or drive away the attacking fleet? We have been shown what modern submarines can do; what prevents them from doing much more?
Shortly after von Weddigen’s great exploit, a German submarine rose to the surface so near the British destroyer Badger that before the undersea boat could submerge again she was rammed, cut open and sunk. One of the most picturesque and least expected features of this war has been the revival of old ways; soldiers are again wearing breastplates and metal helmets and fighting with crossbows and catapults, while against the modern submarine, seamen are effectively using the most ancient of all naval weapons: the ram. It takes two minutes for the average undersea boat to submerge, during which time a thirty-knot destroyer can come charging up from a mile away, with a good chance of scoring a hit with her forward 3- or 4-inch gun, even if she gets there too late to ram. In the case of the U-12, the submarine dived deep enough to get her hull and superstructure out of harm’s way, only to have the top of her conning-tower crushed in by the destroyer as it passed over her. When the inrush of water forced the U-12 to rise to the surface and surrender, her crew discovered that the main hatch could not be opened because one of the periscopes had been bent down across it. Some of them succeeded in climbing out of the torpedo-hatch and jumping overboard before the U-12 went down for good. As she sank stern-foremost, it was observed that both of her bow-tubes were empty; evidence that she had vainly launched two torpedoes at the British flotilla that were hunting her down. Though several British destroyers and torpedo-boats have been sent to the bottom by German submarines, and the English E-9 has sunk the German destroyer S-126, yet the nimble surface torpedo-craft have usually proved too difficult for the undersea boats to hit with their fixed tubes that can only fire straight ahead or astern.
It has been pointed out that the Aboukir, Cressy and Hogue, the Formidable, and the Audacious were all moving slowly and unescorted by any destroyers when they were attacked and sunk. The same was true of the Leon Gambetta and the Giuseppe Garibaldi, when they were sent to the bottom of the Mediterranean by Austrian submarines. Under modern conditions, such isolated big ships are in much the same perilous position as would have been a lonely battery of Union artillery marching through a country swarming with Confederate cavalry. While an escort of destroyers is no sure guarantee against submarine attack, their presence certainly seems to act as a powerful deterrent.
Waters suspected of containing hostile submarines are swept, very much as they would be for mines, by pairs of destroyers or steam trawlers, dragging an arrangement of strong cables between them. Sometimes this is festooned with explosives to blow in the side of any undersea boat it may touch. Usually the vessels engaged in this work use a large net. When they feel the weight of a catch, it is said that they let go the ends and leave it to the submarine’s own twin propellers to entangle themselves thoroughly. An undersea boat so entrapped is helpless to do anything but either sink or else empty her tanks and try to rise and surrender. A submarine in trouble usually sends up notification in the form of large quantities of escaping oil and gas.
Inventors have been busy devising new kinds of traps, snares, and exaggerated lobster-pots to be placed in the waters about the British Isles. How many German submarines have poked their noses into these devices probably not even the British Admiralty could tell, if it was so minded, but the traps are said to have been put down very plentifully and most of the published designs are extremely ingenious.
Individual torpedo-nets for ships have rather gone out of fashion, but the most effective way of keeping submarines out of a harbor is to close its entrance with booms and nettings. The principal naval bases on both sides are undoubtedly so protected. It has been persistently reported that the immunity of British transports crossing the channel is due to a double line of booms, nets and mines stretching from one shore to the other, and enclosing a broad, safe channel outside which the “U-boats” roam hungrily. There would seem to be no great difficulty in building such a barrier, but it would be extremely difficult to keep intact in heavy weather and for that reason most of our naval officers are skeptical of its existence.
Microphones which have been placed under water off the coasts of France, Great Britain, and Ireland have succeeded in detecting the presence of submarines at a distance of fifty-five miles. This device has been perfected by the joint labors of an American electrical engineer, Mr. William Dubilier, and Professor Tissot of the French Academy of Science. These two gentlemen, experimenting with microphones and a submarine placed at their disposal by the French government, “discovered in the course of the tests that the underwater craft were sources of sound waves of exceedingly high frequency, quite distinctive from any other subaqueous sounds. While the cause of the high-pitched sound is known to the inventors, it cannot be divulged since it would then be possible for German submarine constructors to eliminate the source of the tell-tale sound waves, and thus render void the purpose of the detector installation.”[25]
These microphones, it is believed, are usually arranged in a semicircle. Each instrument records sound waves best when they come from one particular direction. The operator on shore, listening to a device that eliminates all other sounds coming in from under the sea, can tell by the way a passing submarine affects the different microphones in the semicircle how far off and in what direction it is moving, and so warns and summons the ever-watchful patrol boats.
Air craft are doubtless being much used in the hunt for submarines, for an aviator at a height of several hundred feet can distinctly see a submarine swimming beneath him in clear water with a good light reflected from the bottom. Early in the war, the pilot and observer of a “Taube” that was brought down in the North Sea were rescued by a British submarine. In the attack on Cuxhaven a combined force of submarines, sea-planes, and light cruisers was resisted by the German shore-batteries, destroyers, “U-boats”, aeroplanes and Zeppelins. As the British sea-planes returned from dropping bombs on the Cuxhaven navy yard or taking observations above the Kiel Canal, some of them were shot down by the Germans but the aviators were picked up, as had been arranged beforehand, by English submarines. In the spring of 1915 there was an engagement between a Zeppelin and a British submarine in which each side claimed the victory. On August 26 of the same year the secretary of the British Admiralty announced:
“Squadron Commander Arthur Bigsworth, R.N., destroyed single-handed a German submarine this morning by bombs dropped from an aeroplane. The submarine was observed to be completely wrecked, and sank off Ostend.