Then came scouting and patrolling, directed by wireless from the shore and intended to cover certain areas of water most commonly used by merchant ships. In this the United States Navy in the last year of the war played a very active and distinguished part. But it was necessary to do a good deal more than merely to get the merchant ships through. The submarines themselves must be destroyed. The sinking of one such craft might prevent the loss of twenty ships. Vulnerable to destroyers and cruisers on the surface, the submarine had only to submerge and rest for a while on the bottom to elude all pursuit. To meet this method of defense, the depth bomb was invented. A destroyer steered at full speed straight to the spot where the submarine had submerged and as she passed it, rolled over the side or stern something not unlike a large tin ash can which sank rapidly and was timed to explode at a depth of from twenty to two hundred feet below the surface. The explosion was effective throughout a wide area, and, unless the submarine was extremely fortunate, the crew of the destroyer, circling back to review results, would be almost sure to see a dark oily smudge appearing, with fragments of clothes and wood.

Then came the "Q" boats, meaning Queer boats. Their purpose was to lure the submarine to the surface, where it could be destroyed by concealed guns. The "Q" boat pretended to be a helpless merchant craft. Here would come puffing along an old rusty tramp steamer with the crew loafing around on deck and all serene. Suddenly, up pops a submarine which signals with gun fire that the ship is to be abandoned. The crew tear around in a panic. The submarine comes closer and becomes impatient. Suddenly a white flag shoots to the masthead; there is a rattle of chains and a clattering down of steel bulkheads; out pops a great rifle, and in fewer seconds than it takes to tell it the submarine is going down, riddled with shot and swept by machine guns.

Such a drama could not be enacted more than a few times. The submarines became exceedingly wary of all innocent-looking craft. In February, 1917, the Q 5 was chugging along when suddenly her commander saw a torpedo coming toward her. With iron nerve he deflected the course of the ship a trifle and allowed the torpedo to hit aft, blowing a hole forty feet wide in her side. The gun crews were already concealed inside; panic stations were ordered; the camouflage crew were rushing around outside in a well-acted confusion; and the boats were lowered and shoved off. Apparently the ship was abandoned, but inside were the commander and the gun crews waiting for the submarine to come up and show herself.

The chief engineer reported that the ship was sinking fast. The commander ordered him to keep the pumps going until the water put the engine fires out. Meanwhile the submarine was watching the ship through its periscope. Slowly it came to within five yards of the boats, not ten yards from the ship itself, observing, watching, well aware that it was difficult to be hit under the water at that angle, and knowing that it could submerge immediately. Despite the fact that his ship was going down the British commander was forced to wait. It was no use to fire until the submarine came up, but apparently the submarine had no intention of coming up until the ship went down.

At last after many anxious minutes, the submarine rose to the surface, and came slowly toward the ship. Patiently the British officer waited until it was near enough for every gun to bear. Then up went the white flag, down clattered the bulkheads, and a terrific gun fire poured upon the doomed vessel. The German commander was complacently climbing out of the conning tower; the first shot neatly beheaded him. The crew of the submarine came pouring out of the hatchways and were swept off by the fire of the machine guns as the submarine sank for the last time. Some hours later, assistance summoned by wireless rescued the men in the small boats, and as the Q 5 was still afloat she was successfully towed back for repairs.

In June, 1917, another "Q" boat went through very much the same sort of stage play to get the submarine to appear. The panic party abandoned the ship and for thirty-five minutes the men on board waited and waited, with the water getting higher every minute. Then a long distance off the periscope of the submarine broke the surface and came toward the ship. As it approached, the submarine submerged, passed under the ship, and came up on the other side out of range. Night was coming on; unless the submarine came up presently there would not be enough light to hit her, and the British boat was going down rapidly.

The men in the boats here tried a new game which completely fooled the German commander. They started pulling for the ship again as if to take possession. This convinced him that the ship had really been abandoned and up came the submarine in a hurry. Open came hatches and the angry Germans began pouring from them with machine guns to shoot the "treacherous Englishmen." It began to look as if the British in the small boats were going to be shot by the submarine and by their own men as well, but they pulled like mad through the range of their own fire.

Then suddenly down clattered the steel screens and a broadside of yellow flame leaped over their heads. Half out of the water, the submarine listed as the oil spouted from the rents in her hull. The crew scrambled out of her hatches, held up their hands, and shouted "Kamerad." The British ceased fire and the submarine rushed off at top speed, attempting to escape, and sweeping into the water to die the poor fellows on her deck. Grimly the British guns broke out again and continued fire until not one remnant was left. They rescued a few of the hapless Germans and were themselves presently rescued by destroyers, waiting around over the horizon for the "Q" boat to finish its task.