Attacking a Vessel at Anchor by coming up from Astern on either Side.—In this case the torpedo is launched when on the quarter of the vessel attacked, as at A, the tow rope left slack. After steaming ahead some distance, hold fast the tow rope, when, by continuing to steam on, the torpedo will diverge into contact with the bottom of the vessel attacked, as shown at [Fig. 112]. When skilfully performed, the total destruction of the enemy is certain, since the torpedo is springing from a depth to the surface, and will, in consequence, strike near her keel. The torpedo vessel can pass at her greatest speed, and, if thought necessary, near enough to clear away any of the ordinary obstructions, such as booms, nets, &c.
Passing Down between Two Lines of Vessels at Anchor.—In this case it would be impossible to fire at the torpedo vessel, for fear of injury to their friends. Two or more torpedo vessels following each other with preconcerted signals would cause great destruction. See [Fig. 113].
Attacking a Vessel in Motion from Right Ahead.—In this case two torpedoes are launched, port and starboard, each diverging to its full extent; when passing the vessel attacked, one or the other of the tow ropes is brought across the cut-water, and by the simultaneous motion of the two vessels in opposite directions, the torpedo is brought alongside of or under the bottom of the vessel attacked, as shown at [Fig. 114]. The torpedo vessel should keep the masts of her enemy in one until close to, when either torpedo will be used, according to the movement of the enemy. At the time of the tow rope taking the cut-water, the brake is suddenly eased up; the tow rope will then pass under the bottom, when by checking the tow rope the torpedo will be hauled under the bottom.
To execute this attack, judgment, skill, and nerve of the highest order will be required, as the risk of being run down will be imminent.
The Attack from Astern.—In this case two torpedoes are launched, and diverged as in the previous case; it is assumed in this instance that the torpedo vessel can outspeed the vessel attacked, which will enable her to bring a torpedo under the run of the attacked vessel, as shown at [Fig. 115].
SYSTEMS OF ATTACK WITH HARVEY'S TOWING TORPEDO.