The duties of our destroyers, in these earliest days, were to hunt for submarines, to escort single ships, to pick up survivors in boats, and to go to the rescue of ships that were being attacked. For the purpose of patrol the sea was divided into areas thirty miles square; and to each of these one destroyer, sloop, or other vessel was assigned. The ship was required to keep within its allotted area, unless the pursuit of a submarine should lead it into a neighbouring one. This patrol, as I have described, was not a satisfactory way of fighting submarines. A vessel would occasionally get a distant glimpse of the enemy, but that was all; as soon as the U-boat saw the ship, it simply dived to security beneath the waves. Our destroyers had many chances to fire at the enemy but usually at very long ranges; some of them had lively scraps, which perhaps involved the destruction of U-boats, though this was always a difficult thing to prove. Yet the mere fact that submarines were seldom sunk by destroyers on patrol, either by ourselves or by the Allies, did not mean that the latter accomplished nothing. The work chiefly expected of destroyers on patrol was that they should keep the U-boats under the surface as much as possible and protect commerce. Normally the submarine sails on top of the water, looking for its prey. As long as it is beyond the merchantmen's range of vision, it uses its high surface speed of about 14 knots to attain a position ahead of the advancing vessel; before the surface vessel reaches a point where its lookout can see the submarine, the U-boat dives and awaits the favourable moment for firing its torpedo. It cannot take these preliminary steps if there is a destroyer anywhere in the neighbourhood; the mere presence of such a warship therefore constitutes a considerable protection to any merchant ship that is within sight. The submarine normally prefers to use its guns on merchant ships, for the torpedoes are expensive and comparatively few in number. Destroyers constantly interfered with these gunning operations. A long distance shot usually was sufficient to make the under-water vessel submerge and thus lose its power for doing harm. The early experiences of our destroyers with submarines were of this kind; but the work of chasing U-boats under the water, escorting a small proportion of the many cargo ships, and picking up survivors, important as it was, did not really constitute effective anti-submarine warfare. It gave our men splendid training, it saved many a merchant ship, it rescued many victims from the extreme dangers of German ruthlessness, it sank a small number of submarines, but it could never have won the war.
This patrol by destroyers and light surface vessels has been criticized as affording an altogether ineffective method of protecting shipping, especially when compared with the convoy system. This criticism is, of course, justified; still we must understand that it was the only possible method until we had enough anti-submarine craft to make the convoy practicable. Nor must we forget that this Queenstown patrol was organized systematically and operated with admirable skill and tireless energy. Most of this duty fell at this time upon the British destroyers, sloops, and other patrol vessels, which were under the command of Admiral Bayly, and these operations were greatly aided by the gallant actions of the British Q-ships, or "mystery ships." Though some of the admirable exploits of these vessels will be recorded in due time, it may be said here that the record which these ships made was not only in all respects worthy of the traditions of their great service, but also that they exhibited an endurance, a gallantry, and seamanlike skill that has few parallels in the history of naval warfare.
II
The headquarters of the convoy system was a room in the British Admiralty; herein was the mainspring of the elaborate mechanism by which ten thousand ships were conducted over the seven oceans. Here every morning those who had been charged with the security of the Allies' lines of communication reviewed the entire submarine situation. Vice-Admiral Sir Alexander L. Duff, R.N., bore this heavy responsibility, ably assisted by a number of British officers. Captain Byron A. Long, U.S.N., a member of my staff, was associated with Admiral Duff in this important work. It was Captain Long's duty to co-ordinate the movements of our convoys with the much more numerous convoys of the Allies; he performed this task so efficiently that, once the convoy organization was in successful operation, I eliminated the whole subject from my anxieties and requested Captain Long not to inform me when troop convoys sailed from the United States or when they were due to arrive in France or England. There seemed to be no reason why both of us should lose sleep over the same cause.
The most conspicuous feature of the convoy room was a huge chart, entirely covering the wall on one side of the office; access to this chart was obtained by ladders not unlike those which are used in shoe stores. It gave a comprehensive view of the North and South American coast, the Atlantic Ocean, the British Isles, and a considerable part of Europe and Africa. The ports which it especially emphasized were Sydney (Cape Breton), Halifax, New York, Hampton Roads, Gibraltar, and Sierra Leone and Dakar, ports on the west coast of Africa. Thin threads were stretched from each one of these seven points to certain positions in the ocean just outside the British Isles, and on these threads were little paper boats, each one of which represented a convoy. When a particular convoy started from New York, one of these paper boats was placed at that point; as it made its way across the ocean, the boat was moved from day to day in accordance with the convoy's progress. At any moment, therefore, a mere glance at this chart, with its multitude of paper boats, gave the spectator the precise location of all the commerce which was then en route to the scene of war.
But there were other exhibits on the chart which were even more conspicuous than these minute representations of convoys. Little circles were marked off in the waters surrounding the British Isles, each one of which was intended to show the location of a German submarine. From day to day each one of these circles was moved in accordance with the ascertained positions of the submarine which it represented, a straight line indicating its course on the chart. Perhaps the most remarkable fact about the Allied convoy service was the minute information which it possessed about the movements of German submarines. A kind of separate intelligence bureau devoted its entire attention to this subject. Readers of detective stories are familiar with the phenomenon known as "shadowing." It is a common practice in the detective's fascinating profession to assign a man, known as a "shadow," to the duty of keeping a particular person under constant observation. With admirable patience and skill an experienced "shadow" keeps in view this object of his attention for twenty-four hours; he dogs him through crowded streets, tracks him up and down high office buildings, accompanies him to restaurants, trolley cars, theatres, and hotels, and unobtrusively chases him through dense thoroughfares in cabs and automobiles. "We get him up in the morning and we put him to bed at night" is the way the "shadow" describes the assiduous care which he bestows upon his unsuspecting victim. In much the same fashion did the Allied secret service "shadow" German submarines; it got each submarine "up in the morning and put it to bed at night." That is to say, the intelligence department took charge of Fritz and his crew as they emerged from their base, and kept an unwearied eye upon them until they sailed back home. The great chart in the convoy room of the Admiralty showed, within the reasonable limits of human fallibility, where each submarine was operating at a particular moment, and it also kept minute track of its performances.
Yet it was not so difficult to gather this information as may at first be supposed. I have already said that there were comparatively few submarines, perhaps not more than an average of eight or nine, which were operating at the same time in the waters south and west of Ireland, the region with which we Americans were most concerned. These boats betrayed their locations in a multitude of ways. Their commanders were particularly careless in the use of wireless. The Germanic passion for conversation could not be suppressed even on the U-boats, even though this national habit might lead to the most serious consequences. Possibly also the solitary submarine felt lonely; at any rate, as soon as it reached the Channel or the North Sea, it started an almost uninterrupted flow of talk. The U-boats communicated principally with each other, and also with the Admiralty at home; and, in doing this, they gave away their positions to the assiduously listening Allies. The radio-direction finder, an apparatus by which we can instantaneously locate the position from which a wireless message is sent, was the mechanism which furnished us much of this information. Of course, the Germans knew that their messages revealed their locations, for they had direction finders as well as we, but the fear of discovery did not act as a curb upon a naturally loquacious nature. And we had other ways of following their movements. The submarine spends much the larger part of its time on the surface. Sailing thus conspicuously, it was constantly being sighted by merchant or military ships, which had explicit instructions to report immediately the elusive vessel, and to give its exact location. Again it is obvious that a submarine could not fire at a merchantman or torpedo one, or even attempt to torpedo one, without revealing its presence. The wireless operators of all merchant vessels were supplied at all times with the longitude and latitude of their ships; their instructions required them immediately to send out this information whenever they sighted a submarine or were attacked by one. In these several ways we had little difficulty in "shadowing" the U-boats. For example, we would hear that the U-53 was talking just outside of Heligoland; this submarine would be immediately plotted on the chart. As the submarine made only about ten knots on the surface, in order to save fuel oil, and much less under the surface, we could draw a circle around this point, and rest assured that the boat must be somewhere within this circle at a given time. But in a few hours or a day we would hear from this same boat again; perhaps it was using its wireless or attacking a merchantman; or perhaps one of our vessels had spotted it on the surface. The news of this new location would justify the convoy officers in moving this submarine on our chart to this new position. Within a short time the convoy officers acquired an astonishingly intimate knowledge of these boats and the habits of their commanders. Indeed, the personalities of some of these German officers ultimately took shape with surprising clearness; for they betrayed their presence in the ocean by characteristics that often furnished a means of identifying them. Each submarine behaved in a different way from the others, the difference, of course, representing the human element in control. One would deliver his attacks in rapid succession, boldly and almost recklessly; another would approach his task with the utmost caution; certain ones would display the meanest traits in human nature; while others—let us be just—were capable of a certain display of generosity, and possibly even of chivalry. By studying the individual traits of each commander we could often tell just which one was operating at a given time; and this information was extremely valuable in the game in which we were engaged.
"Old Hans is out again," the officers in the convoy room would remark.
They were speaking of Hans Rose, the commander of the U-53; this was that same submarine officer who, in the fall of 1916, brought that boat to Newport, Rhode Island, and torpedoed five or six ships off Nantucket. Our men never saw Hans Rose face to face; they had not the faintest idea whether he was fat or lean, whether he was fair or dark; yet they knew his military characteristics intimately. He became such a familiar personality in the convoy room and his methods of operation were so individual, that we came to have almost a certain liking for the old chap. Other U-boat commanders would appear off the hunting grounds and attack ships in more or less easy-going fashion. Then another boat would suddenly appear, and—bang! bang! bang! Torpedo after torpedo would fly, four or five ships would sink, and then this disturbing person would vanish as unexpectedly as he had arrived. Such an experience informed the convoy officers that Hans Rose was once more at large. We acquired a certain respect for Hans because he was a brave man who would take chances which most of his compatriots would avoid; and, above all, because he played his desperate game with a certain decency. Sometimes, when he torpedoed a ship, Rose would wait around until all the lifeboats were filled; he would then throw out a tow line, give the victims food, and keep all the survivors together until the rescuing destroyer appeared on the horizon, when he would let go and submerge. This humanity involved considerable risk to Captain Rose, for a destroyer anywhere in his neighbourhood, as he well knew, was a serious matter. It was he who torpedoed our destroyer, the Jacob Jones. He took a shot at her from a distance of two miles—a distance from which a hit is a pure chance; and the torpedo struck and sank the vessel within a few minutes. On this occasion Rose acted with his usual decency. The survivors of the Jacob Jones naturally had no means of communication, since the wireless had gone down with their ship; and now Rose, at considerable risk to himself, sent out an "S.O.S." call, giving the latitude and longitude, and informing Queenstown that the men were floating around in open boats. It is perhaps not surprising that Rose is one of the few German U-boat commanders with whom Allied naval officers would be willing to-day to shake hands. I have heard naval officers say that they would like to meet him after the war.
We were able to individualize other commanders; the business of acquiring this knowledge, learning the location of their submarines and the characteristics of their boats, and using this vital information in protecting convoys, was all part of the game which was being played in London. It was the greatest game of "chess" which history has known—a game that exacted not only the most faithful and studious care, but one in which it was necessary that all the activities should be centralized in one office. This small group of officers in the Admiralty convoy room, composed of representatives of all the nations concerned, exercised a control which extended throughout the entire convoy system. It regulated the dates when convoys sailed from America or other ports and when they arrived; if it had not taken charge of this whole system, congestion and confusion would inevitably have resulted. We had only a limited number of destroyers to escort all troops and other important convoys arriving in Europe; it was therefore necessary that they should arrive at regular and predetermined intervals. It was necessary also that one group of officers should control the routing of all convoys, otherwise there would have been serious danger of collisions between outward and inward bound ships, and no possibility of routing them clear of the known positions of submarines. The great centre of all this traffic was not New York or Hampton Roads, but London. It was inevitable, if the convoy system was to succeed, that it should have a great central headquarters, and it was just as inevitable that this headquarters should be London.