The great strides that have been made in antisubmarine warfare have tended to obscure its humble beginnings in World War I, and nothing much has ever been written on this subject. The German Navy was the first to use submarines aggressively and in vast numbers. By this means, they hoped to cripple seriously one of their principal opponents, England, Queen of the Seas. And by these actions the Allies suffered great losses, especially of their merchant vessels. These ships were particularly vulnerable, because they were practically unarmed and usually unescorted. The first year or two of the war the British did not consider convoys feasible. It appeared to them beyond reasonable expectation that vessels of different sizes, speeds, types, and nationalities could be assembled and, on short notice, sail in formation, keeping station, and maneuvering together as necessary. When the convoy system was finally adopted by the Allies, the percentage of ship losses was greatly reduced although they were still enormous, mainly because the escorting men-of-war had no effective weapon against enemy submarines.
The U. S. Navy had started working on the problem of an antisubmarine weapon quite some time before the United States entered the war, and the National Electric Signaling Company of Boston had been assigned to this task. Its scientific genius in those days was Professor Reginald A. Fessenden (“Old Fessy” we called him—a charming old man). To guide and guard him and to keep him from absent-mindedly giving away the Navy’s scientific developments, he was constantly accompanied by “Pye” Blake, whose mind was never in the clouds. Assigned as an experimental ship was the USS Aylwin (DD-47), Lieutenant Commander David LeBreton in command. I was the executive officer at that time, and subsequently I would inherit the command.
“Fessy’s” system was very simple. It consisted of a diaphragm for each quadrant of the horizon which would pick up all underwater sound waves, those from its own particular 90 degrees being more pronounced. These sound waves were carried to a “listener” perched in a soundproof cabinet. The diaphragms were placed in the bow of the vessel below water level, and the mode of operation was as follows: when the maximum sound was received in one quadrant, the ship was maneuvered so that this would be one of the bow quadrants (rather than the stern) and then maneuvered so that the maximum sound would be in the adjacent quadrant. When the sounds became equal in each of the bow quadrants the ship obviously was headed directly toward the sound. As you can guess, this took quite a bit of maneuvering plus close co-operation and understanding between the bridge and the “listener.” In addition, the listener had to be trained to distinguish characteristic submarine sounds from all others. All this required the complete co-operation of the entire ship’s company in maintaining silence. It meant shutting down blowers, generators, pumps, and machinery, to stop all noise. To acquire this training, we spent several months at sea operating with “tame subs” which would simulate the wartime tactics of German submarines. After some experimenting, we adopted a “15-minute cycle,” patrolling for 12 minutes and then heaving to with everything shut down for three minutes in order to listen. After a few weeks of practice, we became quite proficient in “pinpointing” the enemy.
Simultaneously with these developments came the introduction of another idea— the “depth charge.” These tins of TNT were about the size of an ordinary ash can and could be dropped over the side or heaved out by “throwers.” They could be set to explode at any desired depth and were found to be effective up to 70 feet; within that radius, they would rupture a submarine’s hull. In order to increase our range, we had four “throwers,” two on each side of the stern, one of which was able to throw about 20 yards and the other about 40. These four, plus the one dropped over the stern, meant five all together. When attacking at full speed, which we expected to do, this meant the firing of our pattern of five charges as rapidly as we could load the throwers. This was facilitated by having the depth charges on racks with rollers. We carried 135 charges which was considered to be quite an arsenal in those days. The Aylwin' s crew had become so good in these simulated “attacks” that we fully expected to be most effective in the war operations; hence we attracted a ship’s company of unusually high-grade volunteers.
Eventually the Aylwin was sent to the war zone. After basing briefly at Queenstown, Ireland, it became apparent that we should base on the English Channel near the area of our operations, first at Portsmouth and later Plymouth. In effect, we were turned over to the British authorities, and they received us with overwhelming cordiality as potential saviors. They co-operated in every way, and kept us informed of all German submarines that were reported. We would immediately proceed to that area to patrol and “listen.” This became almost a daily occurrence and we led very exciting and busy lives. But we soon learned that there was a great difference between operating against a “tame sub” and operating against an enemy submariner who was risking his life. Furthermore, we were handicapped by the comparative shallowness of the English Channel—20 to 40 fathoms. At these depths an enemy submarine on seeing or becoming aware of our presence would “crash dive” to the bottom and maintain absolute silence. The Germans were fully informed about us and we, of course, were very conspicuous. The mere fact that we would repeatedly heave to for three minutes in a dangerous area made the Germans extremely suspicious. Their reasoning was that we were playing a decoy game and simply inviting their attack. Our conspicuousness was aggravated by the fact that we were painted differently from any other ship in the world. Camouflage was then the vogue, and an artist friend of ours had conceived the idea of painting the Aylwin with diagonal and zig-zag stripes in order to obscure her lines, hoping that she would not even be recognizable as a ship. This was, of course, mere wishful thinking.
Having been on independent duty, so to speak, and not having any fleet assignment after the Armistice, the authorities presumably postponed making any ultimate decision about us, and we were assigned to visit all the important European ports. This was, of course, very exciting and led to some interesting adventures. One of our first ports was Hamburg, Germany, and we moored alongside a wharf in the heart of the city. Naturally we attracted the curiosity of many Germans. One of our visitors was a lieutenant in the German Navy who asked us if we had attacked a submarine in St. Georges Channel on 1 September. We had, indeed. He turned out to be one of the submarine’s officers, and accused us of dropping 95 depth charges on them. My reply was that he hadn’t counted them all because we had actually dropped 120. He told me that they had promptly crashed to the bottom and maintained complete silence. Fortunately for them, their hull was still intact. The Aylwin continued her patrolling in that immediate area, and we maintained our “listening,” but did not get a peep of sound. We were beginning to assume that we had been successful but, to play safe, we kept listening for about 36 hours longer when a large convoy came by making a great deal of underwater noise.
After the German submarine heard us depart, she surfaced but discovered that her diving rudders had become completely disabled; therefore, they could not risk any further diving. To avoid the English Channel, the submarine proceeded homeward via the North of Scotland and the North Sea, and with fog and good luck she managed to remain unobserved.
I asked him how he had recognized us, and he said it was because of our distinctive camouflage painting. His answer to the question of why we were never attacked was that the German Navy had issued a general order of caution about the Aylwin and her peculiar tactics including the fact that she was always unaccompanied.
What a long way ASW has come since!