In November, Admiral John Rushworth Jellicoe was appointed Britain’s First Sea Lord; a month later, in response to the growing U-boat threat, he created the Admiralty’s Anti-Submarine Division (ASD). The effect was to re-emphasize the importance of attacking the submarine problem with both research and development, stressing the immediate tactical needs at sea.
One impact was the transfer of the Hawkcraig scientists to the Admiralty Experimental Station at Parkeston Quay, Harwich, where there was access to test ships and laboratory facilities. Ryan would be left to his resourcefulness and his own staff at Hawkcraig. The year 1916 had come to an end, and the United States would soon enter the war. When Rutherford joined other colleagues from Britain and France during a scientific mission to America at the end of May, 1917, the submarine problem was a principal topic (chapter 12). Among the technical discussions, however, it was likely that the friction between British scientists and the military, which had seriously hampered the rapid development of submarine detection devices, was included. To avoid a similar lack of cooperation, U.S. Secretary of the Navy Josephus Daniels, who was aware of British technological developments, created the Special Board on Antisubmarine Devices (chapter 11), which was instrumental in the rapid integration of science and technology into wartime naval requirements.
A FISH, AN EEL, AND A PORPOISE
All such praise the Nash’s fish
Are frankly forced to own,
It’s nothing near as swish
As the porpoise hydrophone19
British P-class vessels were designed primarily for antisubmarine warfare. P-33 is shown here supporting U-boat hunting operations along the northeast shore of Scotland. (Wilson, 1920)
These lines are from a song sung on board a British submarine hunting vessel, P-33, operating off the northern coast of Scotland. By 1918, in addition to destroyers, British antisubmarine work was carried on by motor launches, trawlers, and drifters, as well as larger P-class vessels used in convoy work and capable of twenty-five knots. Hundreds of these various vessels patrolled the waters around the British Isles and into the North Sea, each carrying one or more of the many hydrophone designs available, including those provided by American designers. Lieutenant Wilson, in addition to his work at Hawkcraig with Ryan, also served on P-33. Wilson described the friendly competition between the listeners on his ship and those on the destroyer HMS Dee:
The Nash fish was the rival form, fitted on the Peterhead trawlers, with which Dee and P.33 hunted. When we were ashore, the Club was often the scene of fierce arguments as to the rival merits of Nash’s fish and the porpoise.20
Spring of 1917 had brought about the development of new directional listening devices, but the most important improvement in their capability was providing a streamlined housing, which could be towed behind the hunting vessel. Prior to this, hunting groups had to stop and then deploy their hydrophones for a listening period. When in pursuit, continuous listening while underway was the goal. With the BIR scientists working from the Parkeston experimental station, the Admiralty also encouraged universities and industries to tackle the submarine detection problem. A very promising device was that created by George H. Nash, chief engineer of Western Electric Company’s British subsidiary. Nash began his work with hydrophones early in 1917. His first trials occurred in June, with final acceptance by the Admiralty four months later. His device was comprised of a free-flooding, one-foot diameter cylinder approximately five feet long with conical ends (several versions were built, see top image above). The fish held two hydrophones—one bi-directional, which provided a measure of the direction to the source; and one uni-directional, which the operator could rotate with an electric motor to provide a more precise bearing. All of this was accomplished while the ship was underway.21
A variety of Nash Fish towed listening devices.
A British assembly and test facility. (Courtesy George Malcolmson)
When the BIR scientists moved from Hawkcraig, Commander Ryan continued his hydrophone development unencumbered by the civilian scientists. His inventive mind, however, was also able to tackle the underway pursuit problem. Ryan had designed two systems that could be towed aft of a ship; one referred to as the “porpoise”, the other his “rubber eel.”
Porpoise towed listening devices developed by Captain Ryan at the Hawkcraig Experimental Station. (Wilson, 1920)
We now reach the era of the rubber ‘eel’ and ‘porpoise’ hydrophones…. Both these instruments spelt a new departure. They could be towed from the stern of a vessel under way—a marked advance—and furthermore the latter instrument was a direction finder.22
The rubber eel was available by 1918, with 463 being issued to a variety of vessels, including trawlers and P-class ships. The device was a free-flooding, three-inch diameter rubber cylinder, eighteen inches long—the sensor consisting of a two-inch diameter button microphone with a phosphor-bronze diaphragm. When towed at speeds up to eight knots, the listener could detect a submarine at ranges up to four miles. Because the microphone was non-directional, two eels were often towed and the operator relied on binaural listening to obtain a target bearing.23
Ryan’s most effective device, the porpoise, was not available until September, 1918. The porpoise was similar to the Nash fish, but only carried a single, improved uni-directional hydrophone, also rotated by an electric motor. In comparison trials with the Nash fish, the porpoise had a longer range to detection, performing well at speeds up to six knots. By Armistice, only thirty-one of the one hundred units ordered by Admiral Jellicoe’s Anti-Submarine Division were in operation.24 Nonetheless, the British hydrophone service was glad to have them.
A new school of porpoise instruction was started at Elie for training personnel in its use; and hunting flotillas, using the porpoise, commenced operations in the summer, and carried on until Armistice …”25
Whether hunting at sea or from shore, it was hoped that with all the new technology available, including American listening devices being installed on destroyers and other British submarine hunting vessels, neither a U-boat nor a lovesick mermaid could avoid detection.
CHAPTER 4 HUNTING SUBMARINES FROM SHORE
For the detection of submarines at certain congested lanes near the coast, and at entrances of harbors and bays, the British rather early in the war developed a tripod, with a microphone mounted upon it, which was lowered to the bottom and a listening station established on shore with connection by cable to the tripod.
—Admiral Robert S. Griffin, History of the Bureau of Engineering, 19221
Admiral Griffin, Chief of the U.S. Navy’s Bureau of Engineering, recognized the work of the British early in the war to use shore-based listening stations. During the spring of 1915, Commander Ryan, initially at his station on Inchkeith Island and then at Edinburgh’s Granton Pier, had demonstrated to an anxious Admiralty the application of hydrophones for submarine detection and, in particular,
