The Submarine Torpedo Boat
Its Characteristics And Modern Development

SUBMARINE MINES 197 that any concentrated fleet action was prevented. The contingent result of this strategy was practically the annihilation of the Russian fleet. The plan of attack was to have a mine-layer follow in the wake of the formation of the battle fleet, dropping mines over the stern as she proceeded. The battle fleet would then make a turn and maneuver so as to bring the opposing fleet onto the mine field and to destruction. The Russians were not slow in learning their lesson, how- ever, and soon adopted the same kind of tactics, succeeding in destroying ten of the Japanese ships in this way. There are three types of mines in use at the present time: first, ground mines, which are usually of large dimensions and very heavy. These are laid directly upon the bottom and are used in such places where strong currents would prohibit the use of the ordinary anchored mines; second, anchored mines, which are attached by a cable to a weight on the bottom and held to float at a depth where they will be struck and exploded by passing ships; third, floating mines, which are dropped overboard and float upon the surface until they are run upon by some ship and exploded. The simplest form of mine is the contact mine. It consists of an iron casing which is connected by cable to an anchor weight, the latter being sufficiently heavy to hold it in place. The casing in which the explosive charge is carried is provided with one or more projecting arms or levers which act as triggers. If one of these triggers is struck by a passing vessel, it is driven in against the per- cussion cap causing it to explode and fire the bursting charge. Mines having only one firing pin are designed to roll when struck by a passing ship until the projecting