Since submarines must be hunted, there is something specially attractive in the idea of setting other submarines to hunt them; it seems peculiarly just that while the pirate is lying in wait under water for his victim, he should himself be ambushed by an avenger hiding under the same waters and possessed of the same deadly weapons of offence.

But this method, satisfactory as it is to the imagination, is involved in several practical difficulties. If we put ourselves in the position of a submarine commander with orders to go out and kill U-boats, we shall quickly come up against some of the more obvious of these. The sea is a large place; the submarine moves about it slowly, and therefore takes a long time to patrol a given area. Also the very worst point of view from which to survey that area is the eye-piece of a periscope raised only some two feet above the surface. The strain upon the eye is very severe, when hour after hour is spent in looking for ships of ordinary size, with freeboard, funnels and streamers of smoke. How much more severe, when the object to be looked for is a conning-tower at most, with waves tumbling about it, or possibly only a periscope 4 inches in diameter!

Let us suppose, however, that all the preliminary conditions are as good as they can be; that the commander is in the best of health, with sound nerves and good instruments, and that he is lucky enough to sight a chance near the beginning of his cruise, while his eye is unwearied and his judgment alert. He will still be hampered by two considerations—he must make sure that the boat he is about to attack is an enemy and not a friend, and he must take the not very remote risk of being rammed, bombed, or depth-charged by a British destroyer or a German seaplane, while his attention is fixed entirely on the chase.

Finally, there are the purely technical difficulties of the attack. Manoeuvring for position is not easy, even when the enemy is a large and visible ship of war; it is ten times harder when he is a submerged or nearly submerged vessel, and not steaming straight ahead, but cruising about with sudden and erratic changes of course, as he searches for or sights his intended victims. And here the nature and habits of the torpedo have also to be considered. A periscope, or even a conning-tower, is not a very good object for a distant shot. On the other hand if the range is too short, say less than 250 yards, the torpedo is very likely to miss. This is due to the fact that a torpedo requires a certain length of run before it can settle to its course evenly at the depth for which it is set. It begins by plunging, then rises, sometimes even breaks surface, and finally takes its proper depth, which may be set for anything from 6 to 22 feet. A torpedo fired at a periscope must be set deep, for the submerged part of the boat will be 15 feet or more below the surface. If it were fired at so short a distance as 100 or 120 yards it would reach the target while still on its upward bound, and might easily leap clean over the U-boat’s rounded back. At a still less range, it would probably dive under the enemy altogether. Moreover, up to a distance of 200 yards—or even more—the explosion of a torpedo is dangerous to the attacker as well as to the attacked. Water, being much less elastic than air, conveys the shock of a blow far more completely; and of course, in such a case, a submarine vessel, being entirely surrounded by water, would suffer much more from the concussion than a ship with only part of its hull below the surface.

If we take account of these obvious difficulties, and remember that there are others of which we know nothing, we shall realise that the destruction of a U-boat by one of our own submarines can only be accomplished by a combination of skill, courage, and good fortune. The examples which follow will make this clear.

Let us take first the case of E.54, Lieutenant-Commander Robert H.T. Raikes, which shows a record of two successes within less than four months—one obtained with comparative ease, the other with great difficulty. The first of the two needs no detailed account or comment. E.54, on passage to her patrol ground, had the good fortune to sight three U-boats in succession before she had gone far from her base. At two of these she fired without getting a hit; but the third she blew all to pieces, and picked up out of the oil and debris no less than seven prisoners. Her next adventure was a much more arduous one. She started in mid-August on a seven-day cruise, and in the first four days saw nothing more exciting than a neutral cruiser carrying out target practice. On the morning of the fifth day, a U-boat was sighted at last; and after twenty-five minutes’ manoeuvring, two torpedoes were fired at her, at a distance of 600 yards, with deflection for 11 knots. Her actual speed turned out to be more nearly 6 or 7 knots, and both shots must have missed ahead of her. She dived immediately, and a third torpedo failed to catch her as she went down.

An hour and twenty minutes afterwards she reappeared on the surface, and Lieut.-Commander Raikes tried to cut her off, by steering close in to the bank by which she was evidently intending to pass. E.54 grounded on the bank, and her commander got her off with feelings that can be easily imagined. Less than an hour after, a U-boat—the same or another—was sighted coming down the same deep. Again Lieut.-Commander Raikes tried to cut her off, and again he grounded in the attempt. He was forced to come to the surface when the enemy was still 2,000 yards away. To complete his ill-fortune, another U-boat was sighted within an hour and a quarter, but got away without a shot being possible.

Twenty-four hours later the luck turned, and all these disappointments were forgotten. At 2.6 P.M., Lieut.-Commander Raikes sighted yet another U-boat in open water, on the old practice ground of the neutral cruiser of three days before. He put E.54 to her full speed, and succeeded in overtaking the enemy. By 2.35 he had placed her in a winning position on the U-boat’s bow, and at right angles to her course. At 400 yards’ range he fired two torpedoes, and had the satisfaction to see one of them detonate in a fine cloud of smoke and spray. When the smoke cleared away, the U-boat had entirely disappeared; there were no survivors. Next day, after dark, E.54’s time being up, she returned to her base, having had a full taste of despair and triumph.

Earlier in the year, Lieutenant Bradshaw, in G.13, had had a somewhat similar experience. He went out to a distant patrol in cold March weather and had not been on the ground five hours when his adventures began. At 11.50 A.M. he was blinded by a snow squall; and when he emerged from it, he immediately sighted a large hostile submarine within shot. Unfortunately the U-boat sighted G.13 at the same moment, and the two dived simultaneously. This, as may easily be imagined, is one of the most trying of all positions in the submarine game, and so difficult as to be almost insoluble. The first of the two adversaries to move will very probably be the one to fall in the duel; yet a move must be made sooner or later, and the boldest will be the first to move. Lieutenant Bradshaw seems to have done the right thing both ways. For an hour and a half he lay quiet, listening for any sign of the U-boat’s intentions; then, at 1.30 P.M., he came to the surface, prepared for a lightning shot or an instantaneous manoeuvre. No more complete disappointment could be imagined. He could see no trace of the enemy—he had not even the excitement of being shot at. On the following day he was up early, and spent nearly eleven fruitless hours knocking about in a sea which grew heavier and heavier from the S.S.E. Then came another hour which made ample amends. At 3.55 P.M. a large U-boat came in sight, steering due west. Lieutenant Bradshaw carried out a rapid dive and brought his tubes to the ready; courses and speeds as requisite for attack. (These reports often omit superfluous details, while they bristle with intention.) The manoeuvring which followed took over half an hour, and must have seemed interminably long to everyone in G.13. At 4.30 the enemy made the tension still greater by altering course some 35°. It was not until 4.49 that Lieutenant Bradshaw found himself exactly where all commanders would wish to be, 8 points on the enemy’s bow. He estimated the U-boat’s speed at eight knots, allowed 18° deflection accordingly, and fired twice. It was a long shot in rough water, and he had nearly a minute to wait for the result. Then came the longed-for sound of a heavy explosion. A column of water leaped up, directly under the U-boat’s conning-tower, and she disappeared instantly. Ten minutes afterwards, G.13 was on the surface, and making her way through a vast lake of oil, which lay thickly upon the sea over an area of a mile. In such an oil lake a swimmer has no margin of buoyancy, and it was not surprising that there were no survivors to pick up. The only relics of the U-boat were some pieces of board from her interior fittings. G.13 completed her patrol of twenty-eight days, and returned to her base without sighting another enemy—she had cleared that area for a month.

A successful hunt by Lieutenant North, in command of H.4, resembles G.13’s exploit in many respects, but has this picturesque difference, that it took place in southern waters and in a bright May midnight. It was more than forty-eight hours since H.4 had cast off from the pens before she sighted the quarry she was looking for, 3 points on her port bow. The hour was 11.10 P.M. and the moon was nearly full. Lieutenant North at once turned towards the enemy and went to night action stations. The distance between the two boats was about 1,000 yards, and it was desirable to reduce this to a minimum—say to 250 yards—in order to make sure of a hit in the circumstances. The enemy was a large U-boat and was going about 8 knots, in a course which would bring her across H.4 almost too directly. But she had not advanced more than 300 yards when she altered course 8 points to starboard. Lieutenant North instantly saw his opportunity, turned first to port to cut her off; and then, when his superior speed had made this a certainty, 8 points to starboard to close her. Within four minutes after sighting her, he had placed himself on her port beam at the desired range of 250 yards. He fired two torpedoes. Both hit and detonated, one under the conning-tower, and one in the engine-room. The enemy sank immediately—in fifteen seconds she had gone completely. Then came the usual search for survivors, and two were eventually rescued; they were the captain of the boat and his quartermaster. H.4 combed out the surrounding area thoroughly; but no more could be found; and in view of the presence of prisoners, Lieutenant North at once returned to his base.

It is not to our purpose to enumerate successful shots of the simple and easy kind; one or two examples will stand for a number of these. C.15, for instance, sighted an enemy submarine at 2.43 on a November afternoon, dived and flooded tubes; sighted the U-boat again in the periscope at 3.12; at 3.15 fired at 400 yards. The noise of the explosion was slight, but the enemy—U.C. 65—sank immediately, and C.15 picked up five survivors. D.7, Commander C.G. Brodie, sank U.45 only twenty-two minutes after sighting her, at a range of 1,200 yards. Lieutenant A.W. Forbes, in C.7, sighted a large U-boat on his port quarter, at 3.32 A.M. of a dark and misty April night. He immediately attacked on the surface, and sank her with a single shot at 400 yards. These prompt and successful shots deserve full credit; but every now and then some exceptional circumstance will add a special reason for satisfaction. For example, it is always good to catch a pirate red-handed. Lieut.-Commander G.R.S. Watkins, in E.45, was beginning his day’s patrol at 6.15, on a dim October morning, when he observed flashes on his starboard bow. He altered course in that direction, and after five minutes sighted an unhappy merchantman under fire from a U-boat. He dived at once and approached. At 6.37, he was near enough to see through his periscope that the vessel was a steamer with Dutch colours painted on her side. She was a neutral, and of course unarmed, but such considerations meant nothing to the U-boat pirate, who had ceased fire and was coolly waiting for his victim to sink. He was a large submarine, partially submerged, and by way of further caution he was steering about in figures of 8, with his gun still manned. But, for all his caution, just retribution was upon him. Lieut.-Commander Watkins fired his first shot at 400 yards, and missed—altered course instantly, and in little more than three minutes fired again, from a new angle, two shots in rapid succession. Thirty seconds afterwards, justice was done in full; a loud explosion was heard and there was a tremendous convulsion in the water. For the moment, E.45 was blinded—her periscope was submerged. With a rebound she came to the surface, saw in one quick glance that her enemy was destroyed, and sank again to 60 feet. When she had reloaded, and returned finally to the surface, both pirate and Dutchman had disappeared into the depths.

Lieut.-Commander Vincent M. Cooper, in E.43, also had the satisfaction of surprising an enemy at work. This was a U.C. boat, engaged not in actually firing on merchantmen, but in the still more deadly and murderous business of laying mines for them. When sighted by E.43, she had evidently just come to the surface, as men were observed on the bridge engaged in spreading the bridge screen. Lieut.-Commander Cooper went straight for her at full speed. But as it was 9.30 A.M., and broad daylight, he was forced to remain submerged, and being in shallow water he soon had to slow down. Again and again he bumped heavily on shoals, but fortunately was never quite forced to the surface. After an hour of this he got into deeper water, and was able to go faster. At 11.0 he rose to 24 feet, and took a sight through the periscope. There was the enemy, about 400 yards away on his port beam. He dived, and five minutes later came up for another sight. This time the U-boat was on his port quarter. He turned towards her, but at the moment of attack, when the sights were just coming on, E.43 dipped under a big wave and the chance was spoiled.

Her commander was not to be thrown off; he immediately increased to full speed, altered course, and planned a fresh attack. By 11.17—nearly two hours after beginning the chase—he was in position, 2 points abaft the enemy’s beam at 550 yards’ distance. This time he took every precaution to ensure a kill. On firing he dipped his periscope, so that in case the boat rose suddenly nothing should be visible; and at the same time he yawed to starboard, so as to be ready with another tube if the first shot was a miss. Then came a trying period of suspense and disappointment; he listened in vain for the sound of an explosion, and after forty-five seconds raised his periscope to see what had happened. It was only later, on communicating with his officers and men in the forward and after compartments, that he found, as others have found, how differently sound may affect the different parts of a submarine when submerged. The central compartment may be completely deafened, either by reason of its position, when a detonation occurs directly ahead or astern, or by the much slighter continuous noises of the various electrical machines which are situated there. In this case, the dull report of the under-water explosion, which was not audible to Lieut.-Commander Cooper, was heard in both the other compartments about twenty seconds after he had fired the torpedo.

At the moment when the periscope was raised, the U-boat had disappeared, and there was a great commotion in the water where she had been. E.43 hurried to the spot and found the surface covered with a black oily substance which stuck to the glass of the periscope and put it out of action. Lieut.-Commander Cooper rose to 20 feet and put up his second periscope, but the U-boat was gone and had left no survivors.

E.35 has a chase to her credit, in some respects very similar to this one; but the story is worth adding, because of the masterly precision with which the Commander, Lieutenant D’Oyly Hughes, conducted the manoeuvre and reported it afterwards. At 4 o’clock, on a May afternoon, he sighted in the periscope a low-lying object two to three miles distant on the port beam. His own boat was at 26 feet, and the object was only visible intermittently, when on top of a wave—it was impossible to be certain about it. He turned at once and went straight for it, speeding up as he did so. But this led to immediate difficulties. There was a long breaking swell across his course and a strong wind. Depth keeping was almost impossible, and there was a constant risk of E.35 breaking surface and throwing away her chance. It was necessary to go down to quieter levels, and for some time she travelled at 40 feet with full speed on.

At 4.18, Lieutenant D’Oyly Hughes reduced speed and brought her up again to 26 feet. His first observation, on looking into the periscope, was that the bearing had changed; and secondly, that the floating object was without doubt a large enemy submarine. He headed at once to cut her off—she was making slowly off northwards—and dived to 40 feet in order to increase to full speed himself.

After a twenty-four minutes’ run he slowed down again for periscope observation, ordering the boat to be brought to 23 feet. This was a very anxious moment, for the sea once more all but gave him away. The swell rolled E.35 up till she was actually for an instant breaking surface, within 1,800 yards of the enemy. She was got down again to 26 feet without having been seen, and her commander then very skilfully placed her in the trough of the sea, where he could pursue the chase on a slightly converging course instead of following right astern. On this course, which soon became absolutely parallel to that of the enemy, he remained at periscope depth for another half hour; then at 5.20, observing that he was not gaining fast enough, he dived again to 40 feet and speeded up, at the same time bringing a torpedo-tube to the ‘ready.’ At 5.35 he slowed once more for observation, and found the range had decreased to 1,100 yards. Down he went again for another spurt. At 5.53, he was within 900 yards; but as the parallel courses of the two boats were only a little more than 100 yards apart, he was ‘still very fine on enemy’s port quarter’—the shot was almost a bow-chaser shot and practically hopeless. He dived again, and for twenty-four more minutes patiently continued to observe and spurt alternately.

At 6.17, a dramatic change occurred in the situation. On rising to observe, he found that the enemy, for some irrelevant reason of her own, had turned 16 points to starboard, and was now actually coming back on a course which would bring her down the starboard side of E.35 at a distance of scarcely more than 200 yards. This was much too close for a desirable shot—setting aside the dangers of the explosion, it was not certain that the torpedo would have picked up its depth correctly in so short a run, and a miss might put the U-boat on guard. Still, to manoeuvre for a fresh position would take time and the chance was quite a possible one; the torpedo, at the end of 200 yards, would be at any rate near picking up its depth, and might well make a detonating hit on its upward track—it could not miss for deflection at that range; the enemy’s length was taking up almost the whole width of the periscope. Even if it were a miss underneath, it would probably escape notice, especially in so heavy a sea.

Lieutenant D’Oyly Hughes took exactly one minute to perceive the change of course and the wholly altered situation, to weigh all the above considerations, and to make his decision. At 6.18 he fired, lowered his periscope, put his helm hard a-starboard, and increased his speed. The hydrophone operator heard the torpedo running on her track, but the sound grew fainter and fainter and died away without a detonation. The shot was a miss beneath the target; after more than two long hours, the chase had failed.

The failure was brilliantly redeemed, and with astonishing swiftness. To realise the swiftness and the brilliancy of the manoeuvre which followed, it is necessary to bring it vividly before the mind’s eye. The two boats must be seen at the moment of the first shot, passing one another at 200 yards on opposite courses, E.35 going N.E., and the U-boat S.W. on her starboard beam. At 6.19 the enemy turned a little more towards E.35, and began to steer due west under her stern, happily still without sighting her periscope. E.35 was on her old course, running farther and farther away to the N.E., and there was already some 500 yards between them. But when the U-boat took up her westerly course, Lieutenant D’Oyly Hughes in an instant sent his boat on a swift curve to port, turning in quick succession N., N.W., W., and S.W., till in less than seven minutes after missing his first shot he was bearing down S.S.W. on the enemy, and therefore only 30 degrees abaft her starboard beam and hardly more than 500 yards distant. By pure luck, the unconscious U-boat had at the first critical moment done precisely the right thing to save herself; by sheer skill, the E-boat had been brought back to a winning position. At 6.25 Lieutenant D’Oyly Hughes—coolly estimating speed, distance, and deflection—fired one torpedo at his huge enemy’s fore-turret and another at her after-turret. Both hit where they were aimed to hit. The first made very little noise, but threw up a large column of water and debris. The second did not appear to the eye to produce quite so good a burst; but the noise was louder, and the concussion felt in E.35 was very powerful indeed, the whole boat shaking and a few lights going out momentarily. When the smoke and water column had cleared away, there was nothing to be seen but a quickly expanding calm area, like a wide lake of oil with wreckage floating in it, and three or four survivors clinging to some woodwork. E.35, with her sub-lieutenant, her coxswain, and one able seaman on deck, and life-lines ready, went at once to their rescue; but a second U-boat made her appearance at that moment, and Lieutenant D’Oyly Hughes was obliged to dive at once. Three minutes afterwards, a torpedo passed him on the starboard side; but the new enemy was over two miles away, and though he reloaded his tubes and patrolled submerged on various courses, he never succeeded in picking her up in the periscope. She, also, had no doubt dived, and the two boats had scarcely more chance of coming to action than two men miles apart upon the Downs at midnight.

In such a case, only a lucky chance could bring the duellists together; and even then successful shooting would be difficult. But a bold submarine commander, having once closed, would improvise a new form of attack rather than let a pirate go his way. E.50 was commanded by an officer of this temper when she sighted an enemy submarine, during a patrol off the east coast. Both boats were submerged at the time; but they recognised each other’s nationality by the different appearance of their periscopes. The German had two—thin ones of a light-grey colour, and with an arched window at the top, peculiar to their Service. The British commander drove straight at the enemy at full speed, and reached her before she had time to get down to a depth of complete invisibility. E.50 struck fair between the periscopes; her stem cut through the plates of the U-boat’s shell and remained embedded in her back. Then came a terrific fight, like the death grapple of two primeval monsters. The German’s only chance, in his wounded condition, was to come to the surface before he was drowned by leakage; he blew his ballast tanks and struggled almost to the surface, bringing E.50 up with him. The English boat countered by flooding her main ballast tanks, and weighing her enemy down into the deep. This put the U-boat to the desperate necessity of freeing herself, leak or no leak. For a minute and a half she drew slowly aft, bumping E.50’s sides as she did so; then her effort seemed to cease, and her periscopes and conning-towers showed on E.50’s quarter. She was evidently filling fast; she had a list to starboard and was heavily down by the bows. As she sank, E.50 took breath and looked to her own condition. She was apparently uninjured, but she had negative buoyancy and her forward hydroplanes were jammed, so that it was a matter of great difficulty to get her to rise. After four strenuous minutes she was brought to the surface, and traversed the position, searching for any further sign of the U-boat or her crew. But nothing was seen beyond the inevitable lake of oil, pouring up like the thick rank life-blood of the dead sea-monster.