FIG. 61. THE SUBMARINE AS A DEFENSIVE WEAPON.
Now, as soon as the pursuing ships come within range, the submarines let go their torpedoes at them and these either blow them up, cripple them, or scare them off. In a maneuver of this kind the commander of the fleet executes his retreat in such a way that the heavier-armed pursuing fleet must pass near his submarines, which are usually submerged and are therefore invisible.
The Submarine Flotilla as a Means of Offense.—If, now, the attacking fleet is stronger than the defensive fleet, then the submarines of the attacking fleet will also take an offensive part. In this case the submarines will take up a position to the rear of the defensive fleet.
The commander of the attacking fleet will then use such force on the enemy fleet that it will retreat along the path where the submarines lay, when they will, of course, torpedo them, as shown in [Fig. 62].
Both these methods of attack have been used with signal success in the war that is now going on.
FIG. 62. THE SUBMARINE AS AN OFFENSIVE WEAPON.
The Submarine as a Scout.—Although the submarine is useless as a scout for a swiftly moving fleet still it can render great service as a scout on its own hook.
By way of illustration let us suppose that the enemy has a harbor that is well protected by forts and guns, that her fleet is laying to in it, that we want to know how many ships the fleet is made up of, and, finally, what class of ships they belong to.
It is the duty then of a submarine to get into the harbor and take a general survey of the situation. You may wonder how the craft is to do this, since the harbor is mined; but by skilful handling, the captain will usually get through safely, find out all that he wants to know and run out again.