CHAPTER VIII

SUBMARINE AGAINST SUBMARINE

I

It is not improbable that I have given a false impression concerning the relative merits of the several methods which were developed for fighting the submarine. Destroyers, patrol boats, subchasers, and mystery ships all accomplished great things in solving the most baffling problem presented by the war. The belief is general that the most successful hunter of the submarine was the destroyer, and, so far as absolute figures are concerned, this is true. Destroyers, with their depth charges and their gunfire, sank more U-boats than any other agency. One type of craft, however, proved a more destructive enemy of the submarine than even the destroyer. That was a warship of whose achievements in this direction little has so far been heard. The activities of the German submarine have completely occupied public attention; and this is perhaps the reason why few newspaper readers have suspected that there were other than German and Austrian submarines constantly operating at sea. Everyone has heard of the U-boats, yet how many have heard anything of the H-boats, the E-boats, the K-boats, and the L-boats? The H-, E-, and K-boats were British submarines, and the L-boats were American submarines. In the destruction of the German under-water craft these Allied submarines proved more successful than any kind of surface ship.

The Allied destroyers, about 500 in number, sank 34 German submarines with gunfire and depth charges; auxiliary patrol craft, such as trawlers, yachts, and the like, about 3,000 in number, sank 31; while the Allied submarines, which were only about 100 in number, sank 20.

Since, therefore, the Allies had about five times as many destroyers as submarines at work, it is evident that the record of the latter vessels surpa.s.ses that of the most formidable surface anti-submarine craft.

Thus the war developed the fact that the most deadly enemy of the submarine is the submarine itself. Underwater warfare is evidently a disease in which like cures like. In a way this is the most astonishing lesson of the naval operations. It is particularly interesting, because it so completely demolishes all the ideas on this subject with which we entered the war. From that day in history when the submarine made its first appearance, the one quality which seemed to distinguish it from all other kinds of warship was that it could not be used to fight itself. Writers were fond of pointing out that battleship could fight battleship, that cruiser could fight cruiser, that destroyer could fight destroyer, but that submarine could not fight submarine. This supposed quality, which was constantly emphasized, was what seemed to make the introduction of this strange vessel such a dangerous thing for the British Empire. For more than a hundred years the under-water boat was a weapon which was regarded as valuable almost exclusively to the weaker sea powers. In the course of the nineteenth century this engine of sea fighting made many spectacular appearances; and significantly it was always heralded as the one effective way of destroying British domination at sea.

The inventor of the modern submarine was an undergraduate of Yale named David Bushnell; his famous _Turtle_, according to the great British authority, Sir William White, formerly Chief Naval Constructor of the British navy, contained every fundamental principle of "buoyancy, stability, and control of depth" which are found in the modern submarine; "it cannot be claimed," he said in 1905, "that any new principle of design has been discovered or applied since Bushnell.... He showed the way to all his successors.... Although alternative methods of fulfilling essentials have been introduced and practically tested, in the end Bushnell's plans in substance have been found the best." The chief inspiration of Bushnell's work was a natural hostility to Great Britain, which was at that time engaged in war with his own country; his submarine, invented in 1777, was intended to sink the British warships which were then anch.o.r.ed off the American coast, break the communications of Great Britain with her revolting colonies, and in this way win our liberty. Bushnell did not succeed in this ambitious enterprise for reasons which it is hardly necessary to set forth in this place; the fact which I wish to emphasize is that he regarded his submarine as an agency which would make it possible for the young United States, a weak naval power, to deprive Great Britain, the dominant sea power, of its supremacy. His successor, Robert Fulton, was inspired by a similar ambition. In 1801 Fulton took his _Nautilus_ into the harbour of Brest, and blew a merchant vessel into a thousand pieces; this dramatic experiment was intended to convince Napoleon that there was one way in which he could destroy the British fleet and thus deprive England of her sea control. Dramatic as this demonstration was, it did not convince Napoleon of the value of the submarine; Fulton therefore took his ship to England and exhibited it to William Pitt, who was then Prime Minister. The great statesman was much impressed, but he did not regard the submarine as an innovation that should arouse much enthusiasm in England. "If we adopt this kind of fighting," he said, "it will be the end of all navies."

Despite his own forebodings, Pitt sent Fulton to St. Vincent, who was then the First Lord of the Admiralty.

"Pitt is the biggest fool in the world," remarked the head of the victorious British navy. "Why does he encourage a kind of warfare which is useless to those who are the masters of the sea, and which, if it succeeds, will deprive them of this supremacy?"

The reason for St. Vincent's opposition is apparent. He formed the conception of the submarine which has prevailed almost up to the present time. In his opinion, a submarine was a vessel which could constantly remain under the surface, approach great warships unseen and blow them to pieces at will. This being the case, a nation which possessed two or three successfully working engines of this kind could apparently wipe out the entire British fleet. It therefore needed no argument to show that this was a weapon which was hardly likely to prove useful to the British navy. If the submarine could fulfil its appointed mission, it would give the control of the sea to that nation which used it successfully; but since Great Britain already controlled the sea, the new type of war craft was superfluous to her. In the hands of a weak naval power, however, which had everything to gain and nothing to lose, it might supply the means of overthrowing the British Empire. Could one submarine destroy another, it would present no particular menace, for then, in order to control the sea, it would merely be necessary to build a larger under-water fleet than that of any prospective enemy: but how could vessels which spent all their time under the water, in the dark, ever get a chance to come to blows? From these considerations it seemed apparent to St. Vincent and other British experts of his time that the best interests of the British Empire would be served, not by developing the submarine, but by suppressing it. Fulton's biographer intimates that the British Government offered Fulton a considerable amount of money to take his submarine back to America and forget about it; and there is a letter of Fulton's to Lord Granville, saying that "not for 20,000 a year would I do what you suggest." But there seemed to be no market for his invention, and Fulton therefore returned to America and subsequently gave all his time to exploiting the steamboat. On the defensive powers of the under-water vessel he also expressed the prevailing idea.

"Submarine," he said, "cannot fight submarine."

The man who designed the type of submarine which has become the standard in all modern navies, John P. Holland, similarly advocated it as the only means of destroying the British navy. Holland was an American of Irish origin; he was a member of the Fenian brotherhood, and it was his idea that his vessel could be used to destroy the British navy, blockade the British coast, and, as an inevitable consequence, secure freedom for Ireland. This is the reason why his first successful boat was known as the _Fenian Ram_, despite the fact that it was not a "ram" at all. And the point on which Holland always insisted was that the submarine vessel was a unique vessel in naval warfare, because there was no "answer" to it. "There is nothing that you can send against it," he gleefully exclaimed, "not even itself."

Parliamentary debates in the late nineties indicated that British naval leaders entertained this same idea. In 1900, Viscount Goschen, who was then the First Lord of the Admiralty, dismissed the submarine as unworthy of consideration. "The idea of submarine navigation," he said, "is a morbid one. We need pay no attention to the submarine in naval warfare. The submarine is the arm of weaker powers." But Mr.

Arnold-Forster, who was himself soon to become a member of the Admiralty, took exception to these remarks. "If the First Lord," he said, "had suggested that we should not build submarines because the problems which control them are not yet solved, I should have hesitated to combat his argument. But the First Lord has not said so: he has said that the Admiralty did not care to undertake any project for submarines because this type of boat could never be anything but the arm of the feeble. However, if this boat is made practical, the nation which possesses it will cease to be feeble and become in reality powerful.

More than any other nation do we have reason to fear the submarine. It is, therefore, not wise to wait with indifference while other nations work at the solution of this problem without trying to solve it ourselves." "The question of the best way of meeting submarine attack,"

said Viscount Goschen at another time, "is receiving much consideration.

It is in this direction that practical suggestions would be valuable. It seems certain that the reply to this weapon must be looked for in other directions than in building submarine boats ourselves, for it is clear that one submarine cannot fight another."

This prepossession dominated all professional naval minds in all countries, until the outbreak of the Great War. Yet the war had lasted only a few months when the idea was shown to be absurd. Practical hostilities soon demonstrated, as already said, that not only was the submarine able to fight another boat of the same type, but that it was the most effective anti-submarine agency which we possessed--so effective that the British Admiralty at once began the design of a special type of hunting submarine having a high under-water speed.

The fact is that the popular mind, in its att.i.tude toward this new type of craft, is still too much under the spell of Jules Verne. There is still the disposition to look upon the submarine as an insidious vessel which spends practically all of its time under the water, stealthily slinks along, never once betraying its presence, creeps up at will to its enemy and discharges its torpedo. Yet the description which these pages have already given of its operations shows the falsity of this idea. It is important that we should keep constantly in mind the fact that the submarine is only occasionally a submarine; and that for the greater part of its career it is a surface boat. In the long journeys which the German U-boats made from the Heligoland Bight around Scotland and Ireland to those great hunting grounds which lay in the Atlantic trade routes, they travelled practically all the time on the surface of the water. The weary weeks during which they cruised around, looking for their victims, they also spent almost entirely on the surface. There were virtually only two circ.u.mstances which compelled them to disappear beneath the waves. The first of these was the occasion on which the submarine detected a merchant ship; in this case it submerged, for the success of its attempt to torpedo depended entirely upon its operating unseen. The second occasion which made it necessary to submerge was when it spied a destroyer or other dangerous patrolling craft; the submarine, as has been said, could not fight a vessel of this type with much chance of success. Thus the ability to submerge was merely a quality that was utilized only in those crises when the submarine either had to escape a vessel which was stronger than itself or planned to attack one which was weaker.

The time taken up by these disappearances amounted to only a fraction of the total period consumed in a cruise. Yet the fact that the submarine had to keep itself momentarily ready to make these disappearances is precisely the reason why it was obliged to spend the larger part of its time on the surface. The submarine has two sets of engines, one for surface travel and the other for subsurface travel. An oil-engine propels it on the top of the water, but this consumes a large amount of air, and, for this reason, it cannot be used when travelling under the surface. As soon as the vessel dives, therefore, it changes its motive power to an electric motor, which makes no inroads on the oxygen needed for sustaining the life of its crew. But the physical limitation of size prevents the submarine from carrying large storage batteries, which is only another way of saying that its cruising radius under the water is extremely small, not more than fifty or sixty miles. In order to recharge these batteries and gain motive power for subsurface travel, the submarine has to come to the surface. Yet the simple fact that the submarine can accomplish its destructive work only when submerged, and that it can avoid its enemy only by diving, makes it plain that it must always hold itself in readiness to submerge on a moment's notice and remain under water the longest possible time. That is, its storage batteries must always be kept at their highest efficiency; they must not be wasted by unnecessary travelling under the water; the submarine, in other words, must spend all its time on the surface, except those brief periods when it is attempting to attack a merchant ship or escape an enemy. Almost the greatest tragedy in the life of a submarine is to meet a surface enemy, such as a destroyer, when its electric batteries are exhausted. It cannot submerge, for it can stay submerged only when it is in motion, unless it is in water shallow enough to permit it to rest on the bottom. Even though it may have a little electricity, and succeed in getting under water, it cannot stay there long, for its electric power will soon be used up, and therefore it is soon faced with the alternative of coming to the surface and surrendering, or of being destroyed. The success of the submarine, indeed its very existence, depends upon the vessel spending the largest possible part of its time upon the surface, keeping its full supply of electric power constantly in reserve, so that it may be able to dive at a moment's notice and to remain under the water for the maximum period.

This purely mechanical limitation explains why the German submarine was not a submarine in the popularly accepted meaning of that term. Yet the fact that this vessel remained for the greater part of its existence on the surface was no particular disadvantage, so long as it was called upon to contend only with surface vessels. Even with the larger part of its decks exposed the U-boat was a comparatively small object on the vast expanse of the sea. I have already made clear the great disadvantage under which destroyers and other patrolling vessels laboured in their attempts to "hunt" this type of enemy. A destroyer, small as it is, was an immensely larger object than the under-water boat, and the consequence was that the lookout on a submarine, proceeding along on the surface, could detect the patrolling vessel long before it could be observed itself. All the submarine had to do, therefore, whenever the destroyer appeared on the horizon, was to seek safety under water, remain there until its pursuer had pa.s.sed out of sight, and then rise again and resume its operations. Before the adoption of the convoy system, when the Allied navies were depending chiefly upon the patrol--that is, sending destroyers and other surface craft out upon the high seas to hunt for the enemy--the enemy submarines frequently operated in the same areas as the patrol vessels, and were only occasionally inconvenienced by having to keep under the water to conceal their presence. But let us imagine that the destroyer, in addition to its depth charges, its torpedoes, its guns, and its ability to ram, had still another quality. Suppose, for a moment, that, like the submarine, it could steam submerged, put up a periscope which would reveal everything within the radius of a wide horizon, and that, when it had picked up an enemy submarine, it could approach rapidly under the water, and discharge a torpedo. It is evident that such a manoeuvre as this would have deprived the German of the only advantage which it possessed over all other war craft--its ability to make itself unseen.

No destroyer can accomplish any such magical feat as this: indeed, there is only one kind of vessel that can do so, and that is another submarine. This ill.u.s.tration immediately makes it clear why the Allied submarine itself was the most destructive enemy of the German submarine.

When Robert Fulton, John P. Holland, and other authorities declared that the under-water vessel could not fight its own kind, it is evident that they had not themselves foreseen the ways in which their inventions were to be used. They regarded their craft as ships that would sail the larger part of the time under the waves, coming up only occasionally to get their bearings and to take in a fresh supply of air. It was plain to these pioneers that vessels which spent practically all their time submerged could not fight each other, for the sufficient reason that they could not see each other; a combat under these conditions would resemble a prize-fight between two blindfolded pugilists. Neither would such vessels fight upon the surface, for, even though they were supplied with guns--things which did not figure in the early designs of submarines--one boat could decline the combat simply by submerging. In the minds of Fulton and Holland an engagement between such craft would reduce itself to mutual attempts to ram each other under the water, and many fanciful pictures of the early days portrayed exciting deep-sea battles of this kind, in which submarines, looking like mighty sea monsters, provided with huge glaring headlights, made terrific lunges at each other. None of the inventors foresaw that, in such battles as would actually take place, the torpedo would be used, and that the submarine which was defeated would succ.u.mb to one of those same stealthy attacks which it was constantly meditating against surface craft.

Another point of the highest importance is that in a conflict of submarine against submarine the Allied boats had one great advantage over the German. Hans Rose and Valentiner and Moraht and other U-boat commanders, as already explained, had to spend most of their time on the surface in order to keep their batteries fully supplied with electricity, in readiness for the dives that would be necessary when the Allied destroyers approached. But the Allied submarine commander did not have to maintain this constant readiness; the reason, it is hardly necessary to say, is that the Allied submarine had no surface enemies, for there were no German surface craft operating on the high seas; the Grand Fleet at Scapa Flow was carefully attending to that very essential detail. Occasionally, indeed, our submarines were attacked by our own destroyers, but accidents of this kind, though uncomfortably frequent, were not numerous enough to interfere with the operation I have in mind.

The statement seems almost like a contradiction in terms, yet it is entirely true, that, simply because the Allied submarines did not have to hold themselves constantly ready to submerge, they could in fact spend a considerable part of their time under the water, for they were not compelled to economize electric power so strictly. This gave them a great advantage in hunting the U-boats. British and American submarines could fully charge their batteries, drop under water and cruise around with enough speed to maintain a horizontal position at "periscope depth," that is, a depth just sufficient to enable them to project the periscope above the water whenever desired. This speed was so very slow--about one mile an hour--that it could be kept up an entire day without exhausting the electric batteries.

The net result was this: The German submarine necessarily sailed most of the time on the surface with its conning-tower and deck exposed, whereas the Allied submarine when on its hunting grounds, spent all of the daylight hours under water, with only the periscope visible from time to time for a few seconds. Just as the German U-boat could "spot" an Allied destroyer at a great distance without being itself seen, so could the periscope invariably see the German submarine on the surface long before this tiny object came within the view of a U-boat conning-tower. Our submarine commander could remain submerged, sweep the ocean with his periscope until he had picked up the German enemy; then, still under water, and almost invariably unseen, he could steal up to a position within range, and discharge a torpedo into its fragile side. The German submarine received that same treatment which it was itself administering to harmless merchantmen; it was torpedoed without warning; inasmuch, however, as it was itself a belligerent vessel, the proceeding violated no principle of international law.

II

The Allied submarines, like many other patrol craft, spent much of their time in those restricted waters which formed the entrances to the British Isles. Their favourite places were the English Channel, St.

George's Channel, which forms the southern entrance to the Irish Sea, and the northern pa.s.sage-way between Scotland and Ireland. At these points, it may be remembered, the cargo ships could usually be found sailing singly, either entirely unescorted, or escorted inadequately, while on their way to join a convoy or to their destinations after the dispersal of a convoy; these areas were thus almost the only places where the German submarines had much chance of attacking single vessels.

The territory was divided into squares, each one of which was indicated by a letter: and the section a.s.signed to each submarine was known as its "billet." Under ordinary circ.u.mstances, the Allied submarine spent all its time, while patrolling, on its own particular "billet"; only in case the pursuit of an enemy led it outside the "square" was it permissible to leave. Allied submarines also hunted the U-boats in the North Sea on the routes which the latter had to take in coming out or returning through the pa.s.sages in the German mine-fields of the Heligoland Bight, or through the Skager Rack.

As previously explained, in the daytime the Allied submarine remained under the water, its periscope exposed for a short time every fifteen minutes or so, sweeping the sea for a distance of many miles. As soon as darkness set in, the boat usually emerged, began taking in new air and recharging its batteries, the crew seizing the opportunity to stretch their legs and catch a welcome glimpse of the external world. The simple fact that the Allied submarines spent the larger part of their time under water, while the German spent the larger part of their time on the surface, gave our boats a great military advantage over the foe, but it likewise made existence in our submarine service more arduous. Even on the coldest winter days there could be no artificial heat, for the precious electricity could not be spared for that purpose, and the temperature inside the submarine was the temperature of the water in which it sailed. The close atmosphere, heavily laden also with the smell of oil from the engines and the odours of cooking, and the necessity of going for days at a time without a bath or even a wash, added to the discomfort. The stability of a submerged submarine is by no means perfect; the vessel is constantly rolling, and a certain number of the crew, even the experienced men, are frequently seasick. This movement sometimes made it almost impossible to stay in a bunk and sleep for any reasonable period; the poor seaman would perhaps doze off, but a lurch of the vessel would send him sprawling on the deck. One could hardly write, for it was too cold, or read, for there was little light; and because of the motion of the vessel, it was difficult to focus one's eyes on the page. A limited amount of smoking was permitted, but the air was sometimes so vitiated that only the most vigorous and incessant puffing could keep a cigarette alight. One of the most annoying things about the submarine existence is the fact that the air condenses on the sides as the coldness increases, so that practically everything becomes wet; as the sailor lies in his bunk this moisture is precipitated upon him like raindrops. This combination of discomforts usually produced, after spending a few hours under the surface, that mental state commonly known as "dopey."

The usual duration of a "cruise" was eight days, and by the end of that time many of the crew were nearly "all in," and some of them entirely so. But the physical sufferings were the least discomfiting. Any moment the boat was likely to hit one of the mines the Germans were always planting. A danger which was particularly vexatious was that a British or an American submarine was just about as likely to be attacked by Allied surface craft as the Germans themselves. At the beginning, recognition signals were arranged by which it was expected that an Allied under-water craft, coming to the surface, could make its ident.i.ty known to a friendly warship; sometimes these signals succeeded, but more frequently they failed, and the attacks which British and American destroyers made upon their own submarines demonstrated that there was no certainty that such signals would offer any protection. A rather grim order directed all destroyers and other patrol craft to sink any submarine on sight, unless there was positive information that a friendly submarine was operating in the neighbourhood. To a large extent, therefore, the life of our submarine sailors was the same as that of the Germans. Our men know how it feels to have a dozen depth charges explode around them, for not infrequently they have had to endure this sort of thing from their own comrades. Mistakes of this sort, even though not very numerous, were so likely to happen at any time that whenever an Allied submarine saw an Allied destroyer at a distance, it usually behaved just as a German would have behaved under the same conditions: it dived precipitately to the safety of deep water.

Our men, that is, did not care to take the risk of a discussion with the surface craft; it was more prudent to play the part of an enemy. One day one of the American submarines, lying on the surface, saw an American destroyer, and, cheered in their loneliness by the sight of such a friendly vessel, waited for it to approach, making all the identification signals carefully set down in the books. Instead of a cordial greeting, however, about twenty rounds of projectiles began falling about the L-boat, which as hastily as possible dropped to sixty feet under the surface. In a few minutes depth charges began exploding around him in profusion, the plates of the vessel shook violently, the lights went out, and the end seemed near. Making a last effort, the American submarine rose to the surface, sent up all the recognition signals the officers could think of, and this time with success. The destroyer approached, the commander shouting from the bridge:

"Who are you?"

"American submarine _A L-10_."

"Good luck, old man," came a now familiar voice from the bridge. "This is Bill."

The commander of the destroyer and the commander of the submarine had been room-mates at Annapolis!

In other ways our submarine force pa.s.sed through the same experiences as the Germans. Its adventures shed the utmost light upon this campaign against merchantmen which the Germans had depended upon to win the war.

The observer at the periscope was constantly spotting huge Allied merchantmen making their way into port. The great ships sailed on, entirely oblivious of the periscope and the eye of the British or American watcher fixed upon them.

"How easy to sink her!" the observer would say to himself. This game in which the Germans were engaged was a dangerous one, because of Allied anti-submarine craft; but, when it came to attacking merchant ships, it was the easiest thing in the world. After a few weeks in a submarine, it grew upon our men that the wonder was not that the Germans had sunk so many merchant ships, but that they had sunk so few. Such an experience emphasized the conviction, which was prevalent in both the British and American navies, that the Germans were not particularly skilful at the occupation which seemed to be so congenial to them. Indeed, there are few things in the world that appear so absolutely helpless as a great merchant ship when observed through the periscope of an under-water boat.

Whenever an Allied submarine met its enemy the contest was usually a short one. The issue, one way or the other, was determined in a few minutes. On rare occasions there were attempts to ram; almost invariably, however, it was the torpedo which settled the conflict. If our boat happened to be on the surface when it sighted the German, which, however, was very seldom the case, the first manoeuvre was to dive as quickly and as unostentatiously as possible. If it succeeded in getting under before the U-boat discovered its presence, it then crept up, guided only by the periscope, until it had reached a spot that was within range. The combat, as was the case so frequently in this war, was one-sided. The enemy submarine seldom knew its a.s.sailant was anywhere in the neighbourhood; a merchant ship, from its relatively high bridge, could sometimes see the torpedo approach and turn out of its way; but it was almost impossible to see a wake from the low conning-tower or periscope of a submarine, and no one except the observer had a glimpse of the surface. The small size of the submarine was in itself a great protection; we launched many torpedoes, but only occasionally scored a hit. The missile would usually pa.s.s a few feet ahead or astern, or would glide over or under the submerged hulk, perhaps a few inches only saving it from destruction. Once an American torpedo hit its enemy squarely on the side but failed to explode! If the torpedo once struck and functioned, however, it was all over in a few seconds. A huge geyser of water would leap into the air; and the submarine would sometimes rise at the same time, or parts of it would fly in a dozen directions; then the waters would gradually subside, leaving a mammoth oil patch, in which two or three members of the crew might be discovered struggling in the waves. Most of the men in the doomed vessel never knew what had struck them.

Thus, early one evening in May, 1918, the _E-35_, a British submarine, was patrolling its billet in the Atlantic, about two hundred miles west of Gibraltar. About two or three miles on the port beam a long, low-lying object was distinguished on the surface; the appearance was nondescript, but, to the practised eye at the periscope, it quickly took shape as an enemy submarine. As the sea was rather rough, the _E-35_ dived to forty feet; after a little while it ascended to twenty-six, put up the periscope, and immediately saw, not far away, a huge enemy submarine proceeding north at a leisurely pace, never once suspecting that one of its own kind was on its trail. In order to get within range and cut the German off, the Britisher dived again to forty feet, went ahead for twenty minutes with all the speed it could muster, and again came near enough to the surface to put up its periscope. Now it was directly astern; still the British submarine was not near enough for a sure shot, so again it plunged beyond periscope depth, coming up at intervals during the next hour, each time observing with satisfaction that it was lessening the distance between itself and its prey. When the range had been decreased to two hundred and fifty yards, and when the _E-35_ had succeeded in getting in such a position that it could fire its torpedo, the missile was launched in the direction of the foe. But this was only another of the numerous occasions when the shot missed.

Had the German submarine been a surface ship, it would have seen the wake and probably escaped by flight; but still it sailed nonchalantly on its way, never suspecting for a moment that a torpedo had missed its vitals by only a few feet. Soon the _E-35_ crept still closer, and fired two torpedoes simultaneously from its bow tubes. Both hit at the same time. Not a glimpse of the German submarine was seen from that moment. A terrific explosion was heard, a mountain of water rose in the air, then in a few seconds everything was still. A small patch of oil appeared on the surface; this gradually expanded in size until it covered a great area; and then a few German sailors came up and started swimming toward the British vessel.

We Americans had seven submarines based on Berehaven, Ireland, whose "billets" were located in the approaches to the Irish Sea. The most spectacular achievement of any one of our boats was a curious mix-up with a German submarine, the details of which have never been accurately ascertained, but the practical outcome of which was indisputably the sinking of the German boat. After a week's hard work on patrol, the _A L-2_ was running back to her base on the surface when the lookout sighted a periscope. The _A L-2_ at once changed her course, the torpedo was made ready to fire, when the quiet of the summer afternoon was rent by a terrific roar and explosion. It was quite apparent that something exceedingly distressing had happened to the German submarine; the American turned, and made a steep dive, in an attempt to ram the enemy, but failed. Listening with the hydrophone, the _A L-2_ could hear now the whirring of propellers, which indicated that the submarine was attempting to gain surface and having difficulty in doing so, and now and then the call letters of the German under-water signal set, which seemed to show that the vessel was in distress and was sending appeals for aid. According to the Admiralty records, a German submarine operating in that area never returned to port; so it seems clear enough that this German was lost. Commander R. C. Grady, who commanded the American submarine division, believes that the German spotted the American boat before it was itself seen, that it launched a torpedo, that this torpedo made an erratic course (a not infrequent trick of a torpedo) around our ship, returned and hit the vessel from which it started. There are others who think that there were two German submarines in the neighbourhood, that one fired at our boat, missed it, and that its torpedo sped on and struck its mate. Probably the real facts about the happening will never be explained.

Besides the actual sinkings to their credit, the Allied submarines accomplished strategic results of the utmost importance. We had reason to believe that the Germans feared them almost more than any other agency, unless it was the mine. "We got used to your depth charges,"

said the commander of a captured submarine, "and did not fear them; but we lived in constant dread of your submarines. We never knew what moment a torpedo was going to hit us." So greatly did the Germans fear this attack that they carefully avoided the areas in which the Allied under-water boats were operating. We soon learned that we could keep any section free of the Germans which we were able to patrol with our own submarines. It also soon appeared that the German U-boats would not fight our subsurface vessels. At first this may seem rather strange; certainly a combat between two ships of the same kind, size, and armament would seem to be an equal one; the disinclination of the German to give battle under such conditions would probably strike the layman as sheer cowardice. But in this att.i.tude the Germans were undoubtedly right.

The business of their submarines was not to fight warships; it was exclusively to destroy merchantmen. The demand made upon the U-boat commanders was to get "tonnage! tonnage!" Germany could win the war in only one way: that was by destroying Allied shipping to such an extent that the Allied sea communications would be cut, and the supplies of men and munitions and food from the United States shut off. For this tremendous task Germany had an inadequate number of submarines and torpedoes. Only by economizing to the utmost extent on these vessels and these weapons could she entertain any hope of success. Had Germany possessed an unlimited quant.i.ty of submarines and torpedoes, she might perhaps have profitably expended some of them in warfare on British "H-boats" and American "L-boats"; or, had there been a certainty of "getting" an Allied submarine with each torpedo fired, it would have been justifiable to use these weapons, small as was the supply. The fact was, however, that the Allies expended many torpedoes for every submarine sunk; and this was clearly a game which Germany could not afford to play. Evidently the U-boats had orders to slip under the water whenever an Allied submarine was seen; at least this was the almost invariable procedure. Thus the Allied submarines compelled their German enemies to do the one thing which worked most to their disadvantage: that is, to keep submerged when in the same area with our submarines; this not only prevented them from attacking merchantmen, but forced them to consume their electric power, which, as I have already explained, greatly diminished their efficiency as attacking ships.

The operations of Allied submarines also greatly diminished the value of the "cruiser" submarines which Germany began to construct in 1917. These great subsurface vessels were introduced as an "answer" to the convoy system. The adoption of the convoy, as I have already explained, made it ineffective for the Germans to hunt far out at sea. Until the Allies had put this plan into operation, the relatively small German U-boats could go two or three hundred miles into the Atlantic and pick off almost at will the merchant ships, which were then proceeding alone and unescorted. But now the destroyers went out to a point two or three hundred miles from the British coast, formed a protecting screen around the convoy, and escorted the grouped ships into restricted waters. The result of this was to drive the submarines into these coastal waters; here again, however, they had their difficulties with destroyers, subchasers, submarines, and other patrol craft. It will be recalled that no destroyer escort was provided for the merchant convoys on their way across the Atlantic; the Allies simply did not have the destroyers for this purpose. The Germans could not send surface raiders to attack these convoys in mid-ocean, first, because their surface warships could not escape from their ports in sufficient numbers to accomplish any decisive results, and, secondly, because Allied surface warships accompanied every convoy to protect them against any such attack. There was only one way in which the Germans could attack the convoys in mid-ocean. A fleet of great ocean-going submarines, which could keep the sea for two or three months, might conceivably destroy the whole convoy system at a blow. The scheme was so obvious that Germany in the summer of 1917 began building ships of this type. They were about 300 feet long, displaced about 3,000 tons, carried fuel and supplies enough to maintain themselves for three or four months from their base, and, besides torpedoes, had six-inch guns that could outrange a destroyer. By the time the armistice was signed Germany had built about twenty of these ships. But they possessed little offensive value against merchantmen.

The Allied submarines and destroyers kept them from operating in the submarine zone. They are so difficult to manoeuvre that not only could they not afford to remain in the neighbourhood of our anti-submarine craft, but they were not successful in attacking merchant vessels. They never risked torpedoing a convoy, and rarely even a single vessel, but captured a number by means of their superior gunfire. These huge "cruiser submarines," which aroused such fear in the civilian mind when the news of their existence first found its way into print, proved to be the least harmful of any of the German types.

The Allied submarines accomplished another result of the utmost importance. They prevented the German U-boats from hunting in groups or flotillas. All during 1917 and 1918 the popular mind conjured up frightful pictures of U-boat squadrons, ten or fifteen together, lying in wait for our merchantmen or troopships. Hardly a pa.s.senger crossed the ocean without seeing a dozen German submarines constantly pursuing his ship. In a speech which I made to a group of American editors who visited England in September, 1918, I touched upon this point. "I do not know," I told these journalists, "how many submarines you gentlemen saw on the way over here, but if you had the usual experience, you saw a great many. I have seen many accounts in our papers on this subject. If you were to believe these accounts, you could only conclude that many vessels have crossed the ocean with difficulty because submarines were so thick that they sc.r.a.ped all the paint off the vessels' sides. All of these accounts are, of course, unofficial. They get into the American papers in various ways. It is to be regretted that they should be published and thereby give a false impression. Some time ago I saw a letter from one of our men who came over here on a ship bound into the English Channel. This letter was written to his girl. He said that he intended to take the letter on sh.o.r.e and slip it into a post box so that the censor should not see it. The censor did see it and it eventually came to me. This man was evidently intent on impressing on his girl the dangers through which he had pa.s.sed. It related that the vessel on which he had made the voyage had met two or three submarines a day; that two spies were found on board and hanged; and it said, 'When we arrived off our port there were no less than eighteen submarines waiting for us. Can you beat it?'"

Perhaps in the early days of the war the German U-boats did hunt in flotillas; if so, however, they were compelled to abandon the practice as soon as the Allied submarines began to operate effectively. I have already indicated the circ.u.mstances which reduced their submarine operations to a lonely enterprise. In the open sea it was impossible to tell whether a submarine was a friend or an enemy. We never knew whether a submarine on the surface was one of our own or a German; as a result, as already said, we gave orders to attack any under-water boat, unless we had absolute knowledge that it was a friend. Unquestionably the Germans had the same instructions. It would therefore be dangerous for them to attempt to operate in groups, for they would have no way of knowing that their supposed a.s.sociate was not an Allied or an American submarine. Possibly, even after our submarines had become exceedingly active, the Germans may have attempted to cruise in pairs; one explanation of the strange adventure of the _A L-2_, as said above, was that there were two U-boats in the neighbourhood; yet the fact remains that there is no well-established case on record in which they did so.

This circ.u.mstance that they had to operate singly was a strategic point greatly to our advantage, especially, as I shall describe, when we began transporting American troops.

CHAPTER IX

THE AMERICAN MINE BARRAGE IN THE NORTH SEA