Submarine mines are divided into separate classes, viz.:—
- 1. Mechanical Mines.
- 2. Electrical Mines.
Mechanical Mines.—By this description of submarine mines, is meant those whose charges are fired by mechanical means alone.
Mechanical Mines in the American Civil War.—During the civil war of America (1861-5), the Confederates depended almost entirely on mechanical submarine mines for the protection of their harbours, rivers, etc., and to this extensive use of such mines may be traced nearly the whole of the Federal disasters afloat.
In the principal wars that have subsequently occurred, though this form of submarine mine has been to a certain extent used, it has generally been only as an auxiliary to the more effective electrical torpedo, and owing to the deterrent effect produced by the numerous torpedo successes that characterised the American Civil War, on Naval Commanders, etc., few vessels have been destroyed by their means, the effect of the employment of defensive torpedoes having been almost wholly a moral one.
Mechanical Mines for Coast Defence.—The experience hitherto gained, with regard to the employment of mechanical mines for coast defence in actual war, proves that they will be found exceedingly valuable in the following positions:—
1.—In combination with booms or other obstructions placed in defence of narrow channels, etc., which are intended to be completely blocked up.
2.—In shallow water on the flanks of electrical mines.
3.—In protecting unfrequented bays, channels, etc., and a long line of seacoast, which may otherwise be entirely undefended.