This boat is powered with steam engines and oil-burning boilers which drive the chaser at the very fast speed of 25 knots. The craft is armed with a battery of two 3-inch guns mounted on the fore and aft decks. The large size of this chaser makes it easy for it to cruise for long distances, while its speed is 8 knots faster than that of the fleetest submarine and this makes it a foe that is truly to be feared.
How the Chaser Chases a Submarine.—The way a submarine chaser chases a submarine is like this: each chaser is given a certain area of seaway to patrol. This she does, and if she is lucky she will soon see the periscope of an enemy submarine poking its hood above the water to take a peek around the horizon.
This is the signal for the chaser to bear down on that periscope at full speed, the gunners doing their level best to hit the periscope or any other part of the submarine which shows itself above water.
As it takes time for the submarine to dive or to get her own guns into action, the chaser stands a pretty good chance of either crippling or even sinking her. Further, the submarine cannot use her torpedoes on the chaser, for the latter craft is so short and has such a shallow draft that her hull does not offer much of a target for a torpedo, even though she were standing still, and much less when she is bearing down on the submarine at full speed.
Every once in a while a chaser is able to surprise a submarine when she has come to the surface for a breather and to recharge her storage batteries. When this happens it is simply another case of the cat eating the canary.
If the submarine is within two miles of the chaser she cannot get ready to dive and she must either get her own guns in action or else she must try to outrun the chaser, getting ready to dive as she runs and trusting to the Kaiser that she may not be hit in the meantime.
This last course proves disastrous to the submarine nine times out of ten, and so she usually gets her guns into action and a regular little sea battle is fought right then and there.
Shooting the Guns of the Chaser.—Having found, chased, and caught the submarine, the next thing to do is to put her out of commission. On the guns with which the chaser is armed, and on her gunners, depend to a large extent the success or the failure of the attack.
A gun which had a long range and a flat trajectory[38] was quick in action, and rapid-firing, was thought to be all that a gun should be for submarine execution; and it was all right for shooting at conning towers and similar targets which showed themselves above the water-line, but it was useless for a gun of this kind to try to hit anything that was even a few feet under water.
The reasons for this are somewhat deep and scientific but if you will read carefully, look at the diagrams shown in [Figs. 66] and [67], and do a little thinking as you go along you will be able to visualize the whole thing—that is, to see it.