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 a.s.sailing 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 ill.u.s.tration 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 a.s.sisted 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 a.s.signed 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 antic.i.p.ate 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 a.s.signed 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 quant.i.ties 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 manoeuvres 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 a.s.sistant 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 antic.i.p.ated; 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 mult.i.tude 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.
I do not think that the whole lot contained 1 per cent. of graduates of Annapolis or 5 per cent. of experienced sailors; for the greater number that terrible trip in the icy ocean, with the thermometer several degrees below zero, and with very little artificial heat on board, was their first experience at sea. Yet there was not the slightest sign of whimpering or discouragement. Ignorant of salt water as these men at that time were, they really represented about the finest raw material in the nation for this service. Practically all, officers and men, were civilians; a small minority were amateur yachtsmen, but the great ma.s.s were American college undergraduates. Boys of Yale, Harvard, Princeton--indeed, of practically every college and university in the land--had dropped their books, left the comforts of their fraternity houses, and abandoned their athletic fields, eager for the great adventure against the Hun. If there is any man who still doubts what the American system of higher education is doing for our country, he should have spent a few days at sea with these young men. That they knew nothing at first about navigation and naval technique was not important; the really important fact was that their minds were alert, their hearts filled with a tremendous enthusiasm for the cause, their souls clean, and their bodies ready for the most exhausting tasks. Whenever I get to talking of the American college boys and other civilians in our navy, I find myself indulging in what may seem extravagant praise. I have even been inclined to suggest that it would be well, in the training of naval officers in future, to combine a college education with a shorter intensive technical course at the Naval Academy. For these college men have what technical academies do not usually succeed in giving--a general education and a general training, which develops the power of initiative, independent thought, an ability quickly to grasp intricate situations, and to master, in a short time, almost any practical problem. At least this proved to be the case with our subchaser forces.
So little experience did these boys have of seafaring that, as soon as they had completed their first voyage, we had to place a considerable portion in hospital to recover from seasickness. Yet, a few months afterward, we could leave these same men on the bridge at night in command of the ship. When they reached New London they knew no more of seamanship and navigation than so many babies, but so well were these boys instructed and trained within a few weeks by the regular officers in charge that they learned their business sufficiently well to cross the Atlantic safely in convoy. The early 80-foot subchasers which we built for Great Britain and France crossed the ocean on the decks of ocean liners; for it would have been a waste of time, even if international law had permitted it, to send them under their own power; but all of the 110-footers which these young men commanded crossed the ocean under their own power and many in the face of the fierce January and February gales, almost constantly tossed upon the waves like pieces of cork. As soon as they were sufficiently trained and prepared to make the trip, groups were despatched under escort of a naval vessel fitted to supply them with gasolene at sea. Such matters as gunnery these young men also learned with lightning speed. The most valuable were those who had specialized in mathematics, chemistry, and general science; but they were all a splendid lot, and to their spirit and energy are chiefly due their remarkable success in learning their various duties.
"Those boys can"t bring a ship across the ocean!" someone remarked to Captain Cotten, who commanded the first squadron of subchasers to arrive at Plymouth, after he had related the story of one of these voyages.
"Perhaps they can"t," replied Captain Cotten--himself an Annapolis man who admires these reservists as much as I do. "But they have."
And he pointed to thirty-six little vessels lying at anchor in Plymouth Harbour, just about a hundred yards from the monument which marks the spot from which the _Mayflower_ sailed for the new world--all of which were navigated across by youngsters of whom almost none, officers or men, had had any nautical training until the day the United States declared war on Germany.
Capable as they were, however, I am sure that these reservists would be the first to acknowledge their obligations to the loyal and devoted regular officers of the Navy, who laboured so diligently to train them for their work. One of the minor tragedies of the war is that many of our Annapolis men, whose highest ambition it was to cross the ocean and engage in the "game," had to stay on this side, in order to instruct these young men from civil life.
I wish that I had the s.p.a.ce adequately to acknowledge the work in organization done by Captain John T. Tompkins; in listening devices by Rear-Admiral S. S. Robison, Captains Frank H. Schofield, Joseph H.
Defrees, Commanders Clyde S. McDowell, and Miles A. Libbey, and the many scientists who gave us the benefit of their knowledge and experience. It is impossible to overpraise the work of such men as Captains Arthur J.
Hepburn, Lyman A. Cotten, and William P. Cronan, in "licking" the splendid raw material into shape. Great credit is also due to Rear-Admiral T. P. Magruder, Captains David F. Boyd, S. V. Graham, Arthur Crenshaw, E. P. Jessop, C. M. Tozer, H. G. Sparrow, and C. P.
Nelson, and many others who had the actual responsibility of convoying these vessels across the ocean.
I a.s.sume that they will receive full credit when the story of the work of the Navy at home is written; meanwhile, they may be a.s.sured of the appreciation of those of us on the other side who depended so much for success upon their thorough work of preparation.
II
The sea qualities which the subchaser displayed, and the development of listening devices which made it possible to detect all kinds of sounds under water at a considerable distance, immediately laid before us the possibility of direct offensive operations against the submarine. It became apparent that these listening devices could be used to the greatest advantage on these little craft. The tactics which were soon developed for their use made it necessary that we should have a large number of vessels; nearly all the destroyers were then engaged in convoy duty, and we could not entertain the idea of detailing many of them for this more or less experimental work. Happily the subchasers started coming off the ways just in time to fill the need; and the several Allied navies began competing for these new craft in lively fashion.
France demanded them in large numbers to work in co-operation with the air stations and also to patrol her coastal waters, and there were many requests from stations in England, Ireland, Gibraltar, Portugal, and Italy. The question of where we should place them was therefore referred to the Allied Naval War Council, which, at my suggestion, considered the matter, not from the standpoint of the individual nation, but from the standpoint of the Allied cause as a whole.
A general survey clearly showed that there were three places where the subchasers might render the most efficient service. The convoy system had by this time not only greatly reduced the losses, but it was changing the policy of the submarines. Until this system was adopted, sinkings on a great scale were taking place far out at sea, sometimes three or four hundred miles west of Ireland. The submarines had adopted the policy of meeting the unescorted ships in the Atlantic and of torpedoing them long before they could reach the zones where the destroyer patrol might possibly have protected them. But sailing great groups of merchantmen in convoys, surrounded by destroyers, made this an unprofitable adventure, and the submarines therefore had to change their programme. The important point is that the convoys, so long as they could keep formation, and so long as protecting screens could be maintained on their flanks, were virtually safe. Under these conditions sinkings, as already said, were less than one-half of 1 per cent. These convoys, it will be recalled, came home by way of two "trunk lines," a southern one extending through the English Channel and a northern one through the so-called "North Channel"--the latter being the pa.s.sage between Ireland and Scotland. As soon as the inward-bound southern "trunk-line" convoys reached the English Channel they broke up, certain ships going to Plymouth, Portsmouth, Southampton, and other Channel ports, and others sailing to Brest, Cherbourg, Havre, and other harbours in France. In the same fashion, convoys which came in by way of the North Channel split up as soon as they reached the Irish Sea. In other words, the convoys, as convoys, necessarily ceased to exist the moment that they entered these inland waters, and the ships, as individual ships, or small groups of ships, had to find their way to their destinations unescorted by destroyers, or escorted most inadequately.
This was the one weak spot in the convoy system, and the Germans were not slow to turn it to their advantage. They now proceeded to withdraw most of their submarines from the high seas and to concentrate them in these restricted waters. In April, 1917, the month which marked the high tide of German success, not far from a hundred merchant ships were sunk in an area that extended about 300 miles west of Ireland and about 300 miles south. A year afterward--in the month of April, 1918--not a single ship was sent to the bottom in this same section of the sea. That change measures the extent to which the convoy saved Allied shipping. But if we examine the situation in inclosed waters--the North Channel, the Irish Sea, St. George"s Channel, and the English Channel--we shall find a less favourable state of affairs. Practically all the sinkings of April, 1918, occurred in these latter areas. In April, 1917, the waters which lay between Ireland and England were practically free from depredations; in the spring of 1918, however, these waters had become a favourite hunting ground for submarines; while in the English Channel the sinkings were almost as numerous in April, 1918, as they had been in the same month the year before.
Thus we had to deal with an entirely new phase of the submarine campaign; the new conditions made it practicable to employ light vessels which existed in large numbers, and which could aggressively hunt out the submarines even though they were sailing submerged. The subchaser, when fitted with its listening devices, met these new requirements, though of course not to the desirable degree of precision we hoped soon to attain with still further improved hydrophones and larger vessels of the Eagle cla.s.s then being built.
The matter was presented to the Allied Naval Council and, in accordance with the unanimous opinion of all of the members, they recommended that of the subchasers then available, a squadron should be based on Plymouth, where it could be advantageously used against the German submarines which were still doing great damage in the English Channel, and that another squadron, based on Queenstown, should similarly be used against the submarines in the Irish Sea.
I was therefore requested to concentrate the boats at these two points, and at once acquiesced in this recommendation.
But another point, widely separated from British waters, also made a powerful plea for consideration. In the Mediterranean the submarine campaign was still a menace. The spring and early summer of 1918 witnessed large losses of shipping destined to southern France, to Italy, and to the armies at Salonika and in Palestine. Austrian and German submarines, operating from their bases at Pola and Cattaro in the Adriatic, were responsible for this destruction. If we could pen these pests in the Adriatic, the whole Mediterranean Sea would become an un.o.bstructed highway for the Allies. A glance at the map indicated the way in which such a desirable result might be accomplished. At its southern extremity the Adriatic narrows to a pa.s.sage only forty miles wide--the Strait of Otranto--and through this restricted area all the submarines were obliged to pa.s.s before they could reach the water where they could prey upon Allied commerce. For some time before the Allied Naval Council began to consider the use of the American subchasers, the British navy was doing its best to keep submarines from pa.s.sing this point. A defensive scheme known, not very accurately, as the "Otranto barrage" was in operation. The word "barrage" suggests an effective barrier, but this one at the base of the Adriatic consisted merely of a few British destroyers of ancient type and a large number of drifters, which kept up a continuous patrolling of the gateway through which the submarines made their way into the Mediterranean. It is no reflection upon the British to say that this barrage was unsatisfactory and inadequate, and that, for the first few months, it formed a not particularly formidable obstruction. So many demands were made upon the British navy in northern waters that it could not spare many vessels for this work; the Italian navy was holding the majority of its destroyers intact, momentarily prepared for a sortie by the Austrian battle fleet; the Otranto barrage, therefore, important as it was to the Allied cause, was necessarily insufficient. The Italian representatives at the Allied Council made a strong plea for a contingent of American subchasers to reinforce the British ships, and the British and French delegates seconded this request.
In the spring of 1918 I therefore sent Captain Leigh to southern Italy to locate and construct a subchaser base in this neighbourhood. After inspecting the territory in detail Captain Leigh decided that the Bay of Govino, in the island of Corfu, would best meet our requirements. The immediate connection which was thus established between New London and this ancient city of cla.s.sical Greece fairly ill.u.s.trates how widely the Great War had extended the horizon of the American people. There was a certain appropriateness in the fact that the American college boys who commanded these little ships--not much larger than the vessel in which Ulysses had sailed these same waters three thousand years before--should have made their base on the same island which had served as a naval station for Athens in the Peloponnesian War, and which, several centuries afterward, had been used for the same purpose by Augustus in the struggle with Antony. And probably the sight of the Ach.e.l.leion, the Kaiser"s palace, which was not far from this new American base, was not without its influence in constantly reminding our young men of the meaning of this unexpected a.s.sociation of Yankee-land with the ancient world.
III
By June 30, 1918, two squadrons of American chasers, comprising thirty-six boats, had a.s.sembled at Plymouth, England, under the command of Captain Lyman A. Cotten, U.S.N. The U.S. destroyer _Parker_, commanded by Commander Wilson Brown, had been a.s.signed to this detachment as a supporting ship. The area which now formed the new field of operations was one which was causing great anxiety at that time. It comprehended that section of the Channel which reached from Start Point to Lizard Head, and included such important shipping ports as Plymouth, Devonport, and Falmouth. This was the region in which the convoys, after having been escorted through the submarine zone, were broken up, and from which the individual ships were obliged to find their way to their destinations with greatly diminished protection. It was one of the most important sections in which the Germans, forced to abandon their submarine campaign on the high seas, were now actively concentrating their efforts. Until the arrival of the subchasers sinkings had been taking place in these waters on a considerable scale. In company with a number of British hunting units, Captain Cotten"s detachment kept steadily at work from June 30th until the middle of August, when it became necessary to send it elsewhere. The historical fact is that not a single merchant ship was sunk between Lizard Head and Start Point as long as these subchasers were a.s.sisting in the operations. The one sinking which at first seemed to have broken this splendid record was that of the _Stockforce_; this merchantman was destroyed off Dartmouth; but it was presently announced that the _Stockforce_ was in reality a "mystery" ship, sent out for the express purpose of being torpedoed, and that she "got" the submarine which had ended her own career. This happening therefore hardly detracted from our general satisfaction over the work done by our little vessels. Since many ships had been sunk in this area in the month before they arrived, and since the sinkings started in again after they had left, the immunity which this region enjoyed during July and August may properly be attributed largely to the American navy. Not only were no bona-fide merchant ships destroyed, but no mines were laid from Start Point to Lizard Head during the time that the American forces maintained their vigil there. That this again was probably not a mere coincidence was shown by the fact that, the very night after these chasers were withdrawn from Plymouth, five mines were laid in front of that harbour, in preparation for a large convoy scheduled to sail the next day.
By the time that Captain Cotten"s squadron began work the hunting tactics which had been developed during their training at New London had been considerably improved. Their procedure represented something entirely new in naval warfare. Since the chasers had to depend for the detection of the foe upon an agency so uncertain as the human ear, it was thought to be necessary, as a safeguard against error, and also to increase the chances of successful attack, that they should hunt in groups of at least three. The fight against the submarine, under this new system, was divided into three parts--the search, the pursuit, and the attack. The first chapter included those weary hours which the little group spent drifting on the ocean, the lookout in the crow"s nest scanning the surface for the possible glimpse of a periscope, while the trained listeners on deck, with strange little instruments which somewhat resembled telephone receivers glued to their ears, were kept constantly at tension for any noise which might manifest itself under water. It was impossible to use these listening devices while the boats were under way, for the sound of their own propellers and machinery would drown out any other disturbances. The three little vessels therefore drifted abreast--at a distance of a mile or two apart--their propellers hardly moving, and the decks as silent as the grave; they formed a new kind of fishing expedition, the officers and crews constantly held taut by the expectation of a "bite." And frequently their experience was that of the proverbial "fisherman"s luck." Hours pa.s.sed sometimes without even the encouragement of a "nibble"; then, suddenly, one of the listeners would hear something which his experienced ear had learned to identify as the propellers and motors of a submarine. The great advantage possessed by the American tubes, as already said, was that they gave not only the sound, but its direction.
The listener would inform his commanding officer that he had picked up a submarine. "Very faint," he would perhaps report, "direction 97"--the latter being the angle which it made with the north and south line.
Another appliance which now rendered great service was the wireless telephone. The commanding officer at once began talking with the other two boats, asking if they had picked up the noise. Unless all three vessels had heard the disturbance, nothing was done; but if all identified it nearly simultaneously, this unanimity was taken as evidence that something was really moving in the water. When all three vessels obtained the direction as well as the sound it was a comparatively simple matter to define pretty accurately its location.
The middle chaser of the three was the flagship and her most interesting feature was the so-called plotting-room. Here one officer received constant telephone reports from all three boats, giving the nature of the sounds, and, more important still, their directions. He transferred these records to a chart as soon as they came in, rapidly made calculations, and in a few seconds he was able to give the location of the submarine. This process was known as obtaining a "fix." The reports of our chaser commanders are filled constantly with reference to these "fixes"--the "fix" being that point on the surface of the ocean where three lines, each giving the direction of the detected sound, cross one another. The method can be most satisfactorily ill.u.s.trated by the following diagram:
[Ill.u.s.tration: HOW THE LISTENING DEVICES LOCATED A SUBMARINE.]
In this demonstration the letters A, B, and C, each represent a subchaser, the central one, B, being the flagship of the division. The listener on A has picked up a noise, the direction of which is indicated by the line _a a_. He telephones by wireless this information to the plotting-room aboard the flagship B. The listeners on this vessel have picked up the same sound, which comes from the direction indicated by the line _b b_. The point at which these two lines cross is the "fix"; it shows the spot in the ocean where the submarine was stationed when the sound was first detected. The reason for having a report from the third subchaser C is merely for the purpose of corroborating the work of the other two; if three observations, made independently, agree in locating the enemy at this point, the commanding officer may safely a.s.sume that he is not chasing a will o" the wisp.
But this "fix" is merely the location of the submarine at the time when it was first heard. In the great majority of cases, however, the submerged vessel is moving; so, rapidly as the men in the plotting-room may work, the German has advanced beyond this point by the time they have finished their calculations. The subchasers, which have been drifting while these observations were being made, now start their engines at full speed, and rush up to the neighbourhood of their first "fix." Arrived there, they stop again, put over their tubes, and begin listening once more. The chances are now that the noise of the submarine is louder; the chasers are getting "warmer." It is not unlikely, however, that the direction has changed, for the submarine, which has listening devices of its own--though the German hydrophones were decidedly inferior to the American--may have heard the subchasers and may be making frantic efforts to elude them. But changing the course will help it little, for the listeners easily get the new direction, and send the details to the plotting-room, where the new "fix" is obtained in a few moments. Thus the subchasers keep inching up to their prey; at each new "fix" the noise becomes louder, until the hunters are so near that they feel justified in attacking. Putting on full speed, all three rush up to the latest "fix," drop depth charges with a lavish hand, fire the "Y" howitzers, each one of which carries two depth charges, meanwhile manning their guns on the chance that the submarine may decide to rise to the surface and give battle. In many of these hunts a destroyer accompanies the subchasers, always keeping at a considerable distance, so that the noise of its propellers will not interfere with the game; once the chasers determine the accurate "fix," they wire the position to this larger ship, which puts on full steam and dashes with the speed of an express train to the indicated spot, and adds ten or a dozen depth charges to those deposited by the chasers.
Such were the subchaser tactics in their perfection; yet it was only after much experience that the procedure began to work with clock-like regularity. At first the new world under the water proved confusing to the listeners at the tubes. This watery domain was something entirely new in human experience. When Dr. Alexander Bell invented his first telephone an attempt was made to establish a complete circuit by using the earth itself; the result was that a conglomerate of noises--moanings, shriekings, howlings, and humming sounds--came over the wire, which seemed to have become the playground of a million devils. These were the noises, hitherto unknown, which are constantly being given out by Mother Earth herself. And now it was discovered that the under-ocean, which we usually think of as a silent place, is in reality extremely vocal. The listeners at the C- and K-tubes heard many sounds in addition to the ones which they were seeking. On the K-tubes a submarine running at full speed was audible from fifteen to twenty miles, but louder noises could be heard much farther away. The day might be bright, the water quiet, and there might not be a ship anywhere within the circle of the horizon, but suddenly the listener at the tube would hear a terrific explosion, and he would know that a torpedo, perhaps forty or fifty miles distant, had blown up a merchantman, or that some merchantman had struck a mine. Again he would catch the unmistakable "chug! chug! chug!" which he learned to identify as indicating the industrious and slow progress of a convoy of twenty or thirty ships. Then a rapid humming noise would come along the wire; that was the whirling propeller of a destroyer. A faint moan caused some bewilderment at first; but it was ultimately learned that this came from a wreck, lying at the bottom, and tossed from side to side by the current; it sounded like the sigh of a ghost, and the frequency with which it was heard told how densely the floor of the ocean was covered with victims of the submarines. The larger animal life of the sea also registered itself upon the tubes. Our listeners, after a little training, could identify a whale as soon as the peculiar noise it made in swimming reached the receivers. At first a school of porpoises increased their perplexities. The "swish! swish!" which marked their progress so closely resembled the noise of a submarine that it used to lead our men astray. But practice in this game was everything; after a few trips the listener easily distinguished between the porpoise and the submarine, though the distinction was so fine that he had difficulty in telling just how he made it. In fact, our men became so expert that, out of the miscellaneous noises which overwhelmed their ears whenever the tubes were dropped into the water, they were able almost invariably to select that of the U-boat.
In many ingenious ways the chasers supplemented the work of other anti-submarine craft. Destroyers and other patrol boats kept track of the foe pretty well so long as he remained on the surface; the business of the chaser, we must remember, was to find him after he had submerged.
The Commander-in-Chief on sh.o.r.e sometimes sent a radio that a German had appeared at an indicated spot, and disappeared beneath the waves; the chasers would then start for this location and begin hunting with their listeners. Aircraft which sighted submarines would send similar messages; convoys that had been attacked, individual ships that had been torpedoed, destroyers which had spotted their prey, only to lose track of it as soon as it submerged, would call upon the chasers to take up the battle where they had abandoned it.
As long as the chasers operated in the waters which I have indicated, those between Start Point and Lizard Head, they "got" no submarine; the explanation was simple, for as soon as the chasers and British hunting vessels became active here, the Germans abandoned this field of operations. This was the reason that the operative area of the Plymouth detachment was extended. Some of the chasers were now sent around Land"s End and up the north Cornish coast, where colliers bound from Wales to France were proving tempting bait for the U-boats; others operated farther out to sea, off the Scilly Islands and west of Brest. In these regions their contacts with the submarine were quite frequent.
There was no U-boat in the German navy which the Allied forces were so ambitious to "get" as the _U-53_. I have already referred to this celebrated vessel and its still more celebrated commander, Captain Hans Rose. It was this submarine, it will be recalled, which had suddenly paid a ceremonious visit to Newport, R.I., in the autumn of 1916, and which, on its way back to Germany, had paused long enough off Nantucket to sink half a dozen British cargo ships. It was the same submarine which sank our own destroyer, the _Jacob Jones_, by a chance shot with a torpedo. Thus Americans had a peculiar reason for wishing to see it driven from the seas. About the middle of August, 1918, we discovered that the _U-53_ was operating in the Atlantic about 250 miles west of Brest. At the same time we learned that two German submarines were coming down the west coast of Ireland. We picked up radio messages which these three boats were exchanging; this made it quite likely that they proposed to form a junction west of Brest, and attack American transports, which were then sailing to France in great numbers. Here was an opportunity for the subchasers. The distance--250 miles to sea--would be a severe strain upon their endurance, but we a.s.signed four hunting units, twelve boats in all, to the task, and also added to this contingent the destroyers _Wilkes_ and _Parker_. On the morning of September 2nd one of these subchaser units picked up a suspicious sound.
A little later the lookout on the _Parker_ detected on the surface an object that looked like a conning-tower, with an upright just forward which seemed to be a mast and sail; as it was the favourite trick of the _U-53_ to disguise itself in this way, it seemed certain that the chasers were now on the track of this esteemed vessel. When this mast and sail and conning-tower suddenly disappeared under the water, these suspicions became still stronger. The _Parker_ put on full speed, found an oilslick where the submarine had evidently been pumping its bilges, and dropped a barrage of sixteen depth charges. But had these injured the submarine? Under ordinary conditions there would have been no satisfactory answer to this question; but now three little wooden boats came up, advanced about 2,000 yards ahead of the _Parker_, stopped their engines, put over their tubes, and began to listen. In a few minutes they conveyed the disappointing news to the _Parker_ that the depth charges had gone rather wild, that the submarine was still steaming ahead, and that they had obtained a "fix" of its position. But the _U-53_, as always, was exceedingly crafty. It knew that the chasers were on the trail; its propellers were revolving so slowly that almost no noise was made; the U-boat was stealthily trying to throw its pursuers off the scent. For two and a half hours the chasers kept up the hunt, now losing the faint noise of the _U-53_, now again picking it up, now turning in one direction, then abruptly in another. Late in the afternoon, however, they obtained a "fix," which disclosed the welcome fact that the submarine was only about 300 yards north of them. In a few minutes four depth charges landed on this spot.
When the waters had quieted the little craft began listening. But nothing was heard. For several days afterward the radio operators could hear German submarines calling across the void to the _U-53_, but there was no answer to their call. Naturally, we believed that this long-sought enemy had been destroyed; about a week later, however, our radios caught a message off the extreme northern coast of Scotland, from the _U-53_, telling its friends in Germany that it was on its way home.
That this vessel had been seriously damaged was evident, for it had made no attacks after its experience with the subchasers; but it apparently had as many lives as a cat, for it was able, in its battered condition, to creep back to Germany around the coast of Scotland, a voyage of more than a thousand miles. The subchasers, however, at least had the satisfaction of having ended the active career of this boat. It was damaged two months before the armistice was signed, but it never recovered sufficiently from its injuries to make another voyage. Yet I must do justice to Captain Rose--he did not command the _U-53_ on this last voyage. It was its only trip during the whole course of the war when he had not commanded it!
The story of the _U-53_ ends with a touch which is characteristically German. It was one of the submarines which were surrendered to the Allies at the signing of the armistice. Its first visitors, on this occasion, were the Americans; they were eager to read its log-book, and to find out just what had happened on this final voyage. The book was on board, and it contained a record of the _U-53"s_ voyages from the day when it was commissioned up to the day when it was surrendered. Two or three pages only were missing; the Germans had ripped out that part which described the encounter with the American subchasers! They were evidently determined that we should never have the satisfaction of knowing to just what extent we had damaged the boat; this was the only revenge they could take on us.
IV
On the morning of September 6th three subchaser units, under the command of Ensign Ashley D. Adams, U.S.N.R.F., were listening at a point about 150 miles west of Land"s End. At about eleven-thirty two of these units detected what was unquestionably the sound of a submarine. Moreover, the usual "fixes" disclosed that the enemy was close at hand; so close that two of the units ran up and dropped their charges. This first attack produced no result on the submarine; the depth charge from one of the howitzers, however, unfortunately landed near one of the chasers, and, though it injured no one, it put that particular unit out of commission.