“The course of the torpedo from the time it is released in the tube by the lever trip is interesting,” said Captain Lake. “These torpedoes are made at a cost of $5,000 each, much of which is spent in testing. With their high charge of explosive placed well forward and a little plunger on the nose, connecting with a percussion cap, their interior presents the same view as that of a large steamship. The officer is a little gyroscope, impelled by compressed air. This in turn may be set from the outside to travel straight forward or on a curve, and by a timing device to change its course after a certain distance. Usually it is set to travel straight beneath the water at a depth of about fifteen feet.
“To insure accuracy the torpedo without explosive charge must be fired many times from a fixed torpedo tube. It is finally inspected and passed. As it leaves the torpedo tube on its last journey the trip releases the compressed air which turns its turbine engine. That in turn revolves the propeller. The rudder, speed and depth of passage are actuated by the gyroscope.
“A torpedo has been fired accurately at a distance of five miles. The distance for accuracy is between fifty yards and one thousand. Owing to the concussion on the ear-drums of those in a submarine the greatest distance compatible with accuracy is sought. As the plunger on the torpedo strikes the vessel it explodes the charge almost directly against the side of the vessel.”
The British naval authorities took measures to guard British shipping in the English Channel by stretching nets over as much of the water, particularly in the narrows, as possible. The nets are made of links of steel. These links are about six or eight inches in diameter and made of one-half inch steel. The nets are similar to those formerly used to guard battleships and large cruisers, but which have now been discarded because a torpedo will puncture the net and the second torpedo, which is fired only a second or two after the first, will go through the hole made by the first and reach the hull of the vessel.
These chain nets are moored very securely and have buoys at the upper edges to hold them in position. Often they are set just as a fisherman sets his nets. When the submarine, like a fish, gets in the pound it cannot get out, and those in the vessel must either die there or take chances on reaching the surface and swimming to shore.