I
Who would ever have thought that a little wooden vessel, displacing only sixty tons, measuring only 110 feet from bow to stern, and manned by officers and crew very few of whom had ever made an ocean voyage, could have crossed more than three thousand miles of wintry sea, even with the help of the efficient naval officers and men who, after training there, convoyed and guided them across, and could have done excellent work in hunting the submarines? We built nearly 400 of these little vessels in eighteen months; and we sent 170 to such widely scattered places as Plymouth, Queenstown, Brest, Gibraltar, and Corfu. Several enemy submarines now lie at the bottom of the sea as trophies of their offensive power; and on the day that hostilities ceased, the Allies generally recognized that this tiny vessel, with the "listening devices" which made it so efficient, represented one of the most satisfactory direct "answers" to the submarine which had been developed by the war. Had it not been that the war ended before enough destroyers could be spared from convoy duty to assist, with their greater speed and offensive power, hunting groups of these tiny craft, it is certain that they would soon have become a still more important factor in destroying submarines and interfering with their operations.
The convoy system, as I have already explained, was essentially an offensive measure; it compelled the submarine to encounter its most formidable antagonist, the destroyer, and to risk destruction every time that it attacked merchant vessels. This system, however, was an indirect offensive, or, to use the technical phrase, it was a defensive-offensive. Its great success in protecting merchant shipping, and the indispensable service which it performed to the cause of civilization, I have already described. But the fact remained that there could be no final solution of the submarine problem, barring breaking down the enemy moral, until a definite, direct method of attacking these boats had been found. A depth charge, fired from the deck of a destroyer, was a serious matter for the submarine; still the submarine could avoid this deadly weapon at any time by simply concealing its whereabouts when in danger of attack. The destroyer could usually sink the submarine whenever it could get near enough; it was for the under-water boat, however, to decide whether an engagement should take place. That great advantage in warfare, the option of fighting or of running away, always lay with the submarine. Until it was possible for our naval forces to set out to sea, find the enemy that was constantly assailing our commerce, and destroy him, it was useless to maintain that we had discovered the anti-submarine tactics which would drive this pest from the ocean for all time. Though the convoy, the mine-fields, the mystery ships, the airplane, and several other methods of fighting the under-water boat had been developed, the submarine could still utilize that one great quality of invisibility which made any final method of attacking it such a difficult problem.
Thus, despite the wonderful work which had been accomplished by the convoy, the Allied effort to destroy the submarine was still largely a game of blind man's buff. In our struggle against the German campaign we were deprived of one of the senses which for ages had been absolutely necessary to military operations—that of sight. We were constantly attempting to destroy an enemy whom we could not see. So far as this offensive on the water was concerned, the Allies found themselves in the position of a man who has suddenly gone blind. I make this comparison advisedly, for it at once suggests that our situation was not entirely hopeless. The man who loses the use of his eyes suffers a terrible affliction; yet this calamity does not completely destroy his usefulness. Such a person, if normally intelligent, gradually learns how to find his way around in darkness; first he slowly discovers how to move about his room; then about his house, then about his immediate neighbourhood; and ultimately he becomes so expert that he can be trusted to walk alone in crowded streets, to pilot himself up and down strange buildings, and even to go on long journeys. In time he learns to read, to play cards and chess, and not infrequently even to resume his old profession or occupation; indeed his existence, despite the deprivation of what many regard as the most indispensable of the senses, becomes again practically a normal process. His whole experience, of course, is one of the most beautiful demonstrations we have of the exquisite economy of Nature. What has happened in the case of this stricken man is that his other senses have come to fill the place of the one which he has lost. Deprived of sight, he is forced to form his contacts with the external world by using his other senses, especially those of touch and hearing. So long as he could see clearly these senses had lain half developed; he had never used them to any extent that remotely approached their full powers; but now that they are called into constant action they gradually increase in strength to a degree that seems abnormal, precisely as a disused muscle, when regularly exercised, acquires a hitherto unsuspected vigour.
This illustration applies to the predicament in which the Allied navies now found themselves. When they attempted to fight the submarine they discovered that they had gone hopelessly blind. Like the sightless man, however, they still had other senses left; and it remained for them to develop these to take the place of the one of which they had been deprived. The faculty which it seemed most likely that they could increase by stimulation was that of hearing. Our men could not detect the presence of the submarine with their eyes; could they not do so with their ears? Their enemy could make himself unseen at will, but he could not make himself unheard, except by stopping his motors. In fact, when the submarine was under water the vibrations, due to the peculiar shape of its propellers and hull, and to its electric motors, produced sound waves that resembled nothing else in art or nature. It now clearly became the business of naval science to take advantage of this phenomenon to track the submarine after it had submerged. Once this feat had been accomplished, the only advantage which the under-water boat possessed over other warcraft, that of invisibility, would be overcome; and, inasmuch as the submarine, except for this quality of invisibility, was a far weaker vessel than any other afloat, the complete elimination of this advantage would dispose of it as a formidable enemy in war.
A fact that held forth hopes of success was that water is an excellent conductor of sound—far better than the atmosphere itself. In the air there are many crosscurrents and areas of varying temperature which make sound waves frequently behave in most puzzling fashion, sometimes travelling in circles, sometimes moving capriciously up or down or even turning sharp corners. The mariner has learned how deceptive is a foghorn; when it is blowing he knows that a ship is somewhere in the general region, but usually he has no definite idea where. The water, however, is uniform in density and practically uniform in temperature, and therefore sound in this medium always travels in straight lines. It also travels more rapidly in water than in the air, it travels farther, and the sound waves are more distinct. American inventors have been the pioneers in making practical use of this well-known principle. Before the war its most valuable applications were the submarine bell and the vibrator. On many Atlantic and Pacific points these instruments had been placed under the water, provided with mechanisms which caused them to sound at regular intervals; an ingenious invention, installed aboard ships, made it possible for trained listeners to pick up these noises, and so fix positions, long before lighthouses or lightships came into view in any but entirely clear weather. For several years the great trans-Atlantic liners have frequently made Nantucket Lightship by listening for its submarine bell. From the United States this system was rapidly extending all over the world.
American inventors were therefore well qualified to deal with this problem of communicating by sound under the water. A listening device placed on board ship, which would reveal to practised ears the noise of a submarine at a reasonable distance, and which would at the same time give its direction, would come near to solving the most serious problem presented by the German tactics. Even before the United States entered the war, American specialists had started work on their own initiative. In particular the General Electric Company, the Western Electric Company, and the Submarine Signal Company had taken up the matter at their own expense; each had a research department and an experimental station where a large amount of preliminary work had been done. Soon a special board was created at Washington to study detection devices, to which each of these companies was invited to send a representative; the board eventually took up its headquarters at New London, and was assisted in this work by some of the leading physicists of our universities. All through the summer and autumn of 1917 these men kept industriously at their task; to such good purpose did they labour that by October of that year several devices had been invented which seemed to promise satisfactory results. In beginning their labours they had one great advantage: European scientists had already made considerable progress in this work, and the results of their studies were at once placed at our disposal by the Allied Admiralties. Moreover, these Admiralties sent over several of their experts to co-operate with us. About that time Captain Richard H. Leigh, U.S.N., who had been assigned to command the subchaser detachments abroad, was sent to Europe to confer with the Allied Admiralties, and to test, in actual operations against submarines, the detection devices which had been developed at the New London station. Captain Leigh, who after the armistice became my chief-of-staff at London, was not only one of our ablest officers, but he had long been interested in detection devices, and was a great believer in their possibilities.
The British, of course, received Captain Leigh cordially and gave him the necessary facilities for experimenting with his devices, but it was quite apparent that they did not anticipate any very satisfactory results. The trouble was that so many inventors had presented new ideas which had proved useless that we were all more or less doubtful. They had been attempting to solve this problem ever since the beginning of the war; British inventors had developed several promising hydrophones, but these instruments had not proved efficient in locating a submarine with sufficient accuracy to enable us to destroy it with depth charges. These disappointments quite naturally created an atmosphere of scepticism which, however, did not diminish the energy which was devoted to the solution of this important problem. Accordingly, three British trawlers and a "P"[6] boat were assigned to Captain Leigh, and with these vessels he spent ten days in the Channel, testing impartially both the British and American devices. No detailed tactics for groups of vessels had yet been elaborated for hunting by sound. Though the ships used were not particularly suitable for the work in hand, these few days at sea demonstrated that the American contrivances were superior to anything in the possession of the Allies. They were by no means perfect; but the ease with which they picked up all kinds of noises, particularly those made by submarines, astonished everybody who was let into the secret; the conviction that such a method of tracking the hidden enemy might ultimately be used with the desired success now became more or less general. In particular the American "K-tubes" and the "C-tubes" proved superior to the "Nash-fish" and the "Shark-fin," the two devices which up to that time had been the favourites in the British navy. The "K-tubes" easily detected the sound of large vessels at a distance of twenty miles, while the "C-tubes" were more useful at a shorter distance. But the greatest advantage which these new listening machines had over those of other navies was that they could more efficiently determine not only the sound but also the direction from which it came. Captain Leigh, after this demonstration, visited several British naval stations, consulting with the British officers, explaining our sound-detection devices, and testing the new appliances in all kinds of conditions. The net result of his trip was a general reversal of opinion on the value of this method of hunting submarines. The British Admiralty ordered from the United States large quantities of the American mechanisms, and also began manufacturing them in England.
About the time that it was shown that these listening devices would probably have great practical value, the first "subchasers" were delivered at New London, Conn. The design of the subchaser type was based upon what proved to be a misconception as to the cruising possibilities of the submarine. Just before the beginning of the Great War most naval officers believed that the limitations of the submarine were such that it could not operate far from coastal waters. Hardly any one, except a few experienced submarine officers, had regarded it as possible that these small boats could successfully attack vessels upon the high seas or remain for any extended period away from their base. High authorities condemned them. This is hard to realize, now that we know so well the offensive possibilities of submarines, but we have ample evidence as to what former opinions were. For example, a distinguished naval writer says that at that time "The view of the majority of admirals and captains probably was that submersible craft were 'just marvellous toys, good for circus performances in carefully selected places in fine weather.'" He adds that certain very prominent naval men of great experience declared that the submarine "could operate only by day in fair weather; that it was practically useless in misty weather"; that it had to come to the surface to fire its torpedo; that its "crowning defect lay in its want of habitability"; that "a week's peace manœuvres got to the bottom of the health of officers and men"; and that "on the high seas the chances [of successful attack] will be few, and submarines will require for their existence parent ships." The first triumph of Otto Weddingen, that of sinking the Cressy, the Hogue, and the Aboukir, did not change this conviction, for these three warships had been sunk in comparatively restricted waters under conditions which were very favourable to the submarine. It was not until the Audacious went to the bottom off the north-west coast of Ireland, many hundreds of miles from any German submarine base, that the possibilities of this new weapon were partially understood; for it was clear that the Audacious had been sunk by a mine, and that that mine must have been laid by a submarine. Even then many doubted the ability of the U-boats to operate successfully in the open sea westward of the British Isles. Therefore the subchaser was designed to fight the submarine in restricted waters; Great Britain and France ordered more than 500 smaller (80-foot) vessels of this type, or of approximately this type, built in the United States; and just before our declaration of war the United States had designed and contracted for several hundred of a somewhat larger size (the 110-foot chasers) with the original idea of using them as patrol boats near the harbours and coastal waters of our own country. Long before these vessels were finished, however, it became apparent that Germany could not engage in any serious, extensive campaign on this side; it was also evident that any vessel as small as the subchaser had little value in convoy work, notwithstanding the excellence of its sea-keeping qualities; and we were all rather doubtful as to just what use we could make of these new additions to our navy.
The work of pushing the design and construction of these boats reflects great credit upon those who were chiefly responsible. The designs were drawn and the first contracts were placed before the United States had declared war. The credit for this admirable work belongs chiefly to Commander Julius A. Furer (Construction Corps) U.S. Navy, and to Mr. A. Loring Swasey, a yacht architect of Boston, who was enrolled as a lieutenant-commander in the reserves, and who served throughout the war as an adviser and assistant to Commander Furer in his specialty as a small vessel designer, particularly in wood. It speaks well for the ability of these officers that the small subchasers exhibited such remarkable sea-keeping qualities; this fact was a pleasant surprise to all sea-going men, particularly to naval officers who had had little experience with that type of craft. The listening devices had not been perfected when they were designed, and this innovation opened up possibilities for their employment which had not been anticipated; for these reasons it inevitably took a large amount of time, after the subchasers had been delivered, to provide the hydrophones and all the several appliances which were necessary for hunting submarines. Apparently those who were responsible for constructing these boats had a rocky road to travel; with the great demand for material and labour for building destroyers, merchant ships, and for a multitude of war supplies, it was natural that the demands for the subchasers in the early days were viewed as a nuisance; the responsible officers, therefore, deserve credit for delivering these boats in such an efficient condition and in such a remarkably short time. That winter, as everyone will recall, was the coldest in the memory of the present generation. Day after day the poor subchasers, coated with ice almost a foot thick, many with their engines wrecked, their planking torn and their propellers crumpled, were towed into the harbour and left at the first convenient mooring, where the ice immediately began to freeze them in. As was inevitable under such conditions, the crews, for the most part, suffered acutely in this terrible weather; they had had absolutely no training in ordinary seamanship, to say nothing of the detailed tactics demanded by the difficult work in which they were to engage.