A Confederate “Buoyant Torpedo” or Contact-mine.
At the siege of Port Arthur in 1904, the Japanese fleet planted mines outside the harbor to keep the Russians in, and the Russians came out and planted mines of their own to entrap the blockaders. While engaged in this work, the Russian mine-layer Yenisei had a mine which had just been lowered through her specially constructed sternports thrown by a wave against her rudder, and was blown to atoms by the consequent explosion of three hundred more in her hold. The flagship Petropavlosk, returning from a sortie on April 13, struck a Japanese contact-mine and went down with the loss of six hundred men, including Vereshchagin, the famous painter of war-scenes, and Admiral Makaroff, who was not only the commander but the heart and soul of the Russian fleet.[22] A month later, another mine cost the Japanese their finest battleship, the Hatsuse. Nor was the loss confined either to the belligerents or to the duration of the war. Nearly one hundred Chinese and other neutral merchant vessels were sunk by some of the many mines torn loose from their anchors by storms to drift, the least noticeable and most terrible of derelicts, over all the seas of the Far East, long after peace was declared.
The same thing on a larger scale will doubtless take place as a result of the present European War. From the Baltic to the Dardanelles, both sides have sown the waters thick with contact mines, hundreds of which have already broken loose and been cast up on the shores of Denmark, Holland, and other neutral lands. How many more have been picked up on the coasts of the different belligerent countries, the military censors have naturally kept a close secret; how many of these infernal machines are now drifting about the North Sea, the North Atlantic, and the Mediterranean it is impossible to compute. Scarcely a week passes without the publication of such news items as the following extracts from “Current events in Norway,” in the “American-Scandinavian Review” for July-August, 1915:
“One hundred and fifty mines had been brought into Bergen up to April 12. The steamer Caprivi of Bergen, which sank after being struck by a mine off the coast of Ireland, was on its way from Baltimore with a cargo of 4150 tons of grain, the property of the Norwegian government.... The German government has declared its willingness to comply with the demand of the Norwegian government for compensation for the Belridge, provided it be proved that the sinking of the steamer was the result of a German torpedo. The pieces of the shell found in the side of the vessel are to be sent to the German government, and in case there should be any disagreement about the facts they will be submitted to arbitration.”
Unfortunately in most cases where a neutral ship is so sunk, the exploding mine automatically destroys all evidence of its own origin, and each belligerent promptly and positively declares that it must have been planted, if not deliberately set adrift, by the other side. The neutral is left to get what satisfaction he can out of the ruling of the last Hague Conference that all contact mines must be so constructed as to become harmless after breaking loose from their moorings. There is nothing mechanically difficult about installing such a safety device, and all the great powers now at war with each other solemnly pledged themselves to do so. But the temptation of perhaps destroying a hostile battleship as the Hatsuse was destroyed, by a drifting mine, has apparently been too great.
Premature explosion of the mine during handling and planting, such as caused the destruction of the Yenisei is, of course, carefully guarded against. One of the simplest and most effective safety devices is that used in the British navy, where the external parts of the exploding apparatus are sealed with a thick layer of sugar, which is dissolved by the sea-water after being submerged for a few minutes. By then the mine-laying vessel has had time to get safely out of the neighborhood.
Modern mines are of various shapes and sizes but are as a rule either spherical or shaped like a pear with the stem down. The anchor is a hollow, flat-bottomed cylinder, containing its own anchor cable wound on a windlass, and making a convenient base or stand for the explosive chamber or mine proper, so that the whole apparatus can be stood or trundled about the deck of a mine-layer like a barrel. Once placed in the water either by being dropped through the overhanging stern-ports of a large sea-going mine-planter like the U.S.S. San Francisco, or lowered over the side of a smaller craft by a derrick boom, the weight of its anchor causes the mine to assume an upright position. This releases a small weight or plummet at the end of a short line attached to a spring that keeps the windlass inside the anchor from revolving. When the plummet has sunk to the end of its cord, its weight pulls down the spring, and the windlass begins to revolve and unreel the cable, the end of which is, of course, made fast to the bottom of the mine. This causes the anchor, which has been held up by the buoyancy of the mine, to sink, and follows the plummet till the latter touches the bottom. Freed of the plummet’s weight, the spring now flies up and stops the windlass. But the hollow anchor is now filled with water, whose additional weight drags the mine under. When the anchor rests on the bottom, the mine will be at the same distance beneath the surface of the water as the anchor had to sink after the windlass stopped, or the length of the plummet’s line. By regulating that, a mine can be made automatically to set itself at any desired depth.
(Redrawn from the London Sphere.)
Modern Contact-Mine.