The Listeners. Roy R. Manstan

      Commander C. P. Ryan was promoted to Acting Captain, October 1, 1916, shown here on one of the vessels used to support his antisubmarine research in the Firth of Forth. (Wilson, 1920)

      Commander Ryan was at his station when U-21 quietly entered the Firth of Forth on September 4, 1914, passing Inchkeith and venturing nearly as far as the Rosyth naval base. Having been spotted and fired on from shore batteries, U-21 made its escape from the Forth at night. The following day, the scout cruiser HMS Pathfinder was seen through U-21’s periscope southeast of the Isle of May, just beyond the entrance to the Forth; by four o’clock that afternoon, a single torpedo sent the British cruiser to the bottom. By the end of September, the loss of Pathfinder, Aboukir, Cressy, and Hogue would dispel any doubts about the efficacy of the U-boat. Asymmetric warfare in the twentieth century had arrived in the form of what war correspondent Lowell Thomas referred to as Raiders of the Deep (1928), which “came within an ace of bringing the combined forces of twenty nations to their knees with their new form of warfare—warfare under the sea.”³ To stop these raiders of the deep, an entirely new concept of antisubmarine warfare would be needed, and that would require another new technology—the hydrophone.

      In 1914, a device that could convert sound energy, in particular a human voice, into electrical energy was relatively new; the microphone had been developed independently during the 1870s in England by David E. Hughes and in America by Emile Berliner and Thomas Edison. At the beginning of the war, any device that could be submerged and generate an electrical signal from underwater sounds was referred to as a hydrophone, consisting of one of a variety of microphone-like devices available at the time, held within a watertight housing. The term “hydrophone” became a generic term for these devices; their efficiencies as submarine detectors, however, varied considerably.

      Some contemporary authors preferred to refer to these devices as “sound receivers,” as did Dr. Harvey C. Hayes (see also chapter 12), writing for the American Philosophical Society in 1920. He distinguished a difference between resonant and non-resonant receivers, important here because, as Hayes pointed out, the “Germans have made use of [resonant receivers] in the listening gear installed on U-boats as have the British in much of their earlier work.”⁴ The resonant receivers were very sensitive to sounds which were of the frequency at which the receiver vibrated most efficiently, but were not sensitive to sounds at other frequencies, making it difficult for a listener to distinguish a submarine from other underwater sounds. According to Hayes, the only advantage of a resonant receiver was that it could detect that specific sound at a much further range than a non-resonant receiver, “providing the submarine gives out sound of the same frequency to which the receiver is tuned …” Hayes then added: “An analysis of the sound emitted by a submarine shows a continuous sound spectrum throughout the range of the audible. No characteristic frequency is emitted.”⁵ Soon, microphone-based non-resonant receivers, including those Commander Ryan began using as he continued his work in the Firth of Forth, became the preferred device, improving as hydrophone development continued. Eventually, as more was learned about the sounds generated by a U-boat, electronic filtering was added “to allow all sounds above a certain definite frequency to pass but eliminate almost entirely the lower frequencies [not associated with a submarine].”⁶

      In spite of the loss of Pathfinder and other naval vessels in 1914, the Admiralty was slow to initiate a serious effort into the detection of a submerged U-boat. The early work by Ryan had not yet received official recognition. He initially relied on any hydrophones available in 1914, which were built similar to those produced by the Submarine Signal Company⁷ for ship to ship (or submarine) communications. Others were cobbled together by Ryan with whatever he could find, including microphones that he installed in housings of his own design. With at least some success that fall, the Admiralty finally recognized the potential of Ryan’s work, and in February, 1915, authorized him to begin formal experiments with his latest device.⁸ Ryan was encouraged to move forward with his ideas, but it was a slow process, while U-boats continued to strike mercantile targets with impunity

      UK SCIENCE AND THE BOARD OF INVENTION AND RESEARCH

      We have produced no counter stroke at all to the enemy’s submarine and no efficient protection against his improved torpedo … we have not produced any novelty at all except in the field of recruiting posters.⁹

      It was June, 1915, when popular science fiction writer H. G. Wells echoed the nation’s concern with the new forms of warfare brought onto the battlefields of Europe and under the seas. The Times enabled Wells’ voice to be heard by individuals within the Government and the Admiralty. Throughout Britain, it had become painfully obvious that Germany had prepared for war, not just through its decades-long development of a strong military, but had engaged that country’s scientific minds in expanding her war-fighting technology. Wells understood the urgent need to match the technological superiority of the enemy. In a letter to The Times, published June 11 and titled “Mobilisation of Invention,” he called for the Government to organize the “scientifically and technically competent men for this highly specialized task.”¹⁰

      Wells was not the only voice that appeared in The Times that June. British scientist Professor J. A. Fleming, referring in particular to the navy, emphasized to The Times readers that there “is no want of ability, but there is an entire absence of external directing power … [and that] … steps have been taken to inhibit scientific activity in directions which might assist the Navy,” lamenting the fact that he had not received “one word of request to serve any committee, co-operate in any experimental work, nor place expert knowledge at the disposal of the Crown.” Sir Phillip Magnus, an educator and Member of Parliament during the war, was insistent, proclaiming that “our scientific men are in no way inferior to those of Germany,” and recommended the creation of a committee of scientists who could provide a critical look at German weaponry, which the allies were facing.¹¹ Parliament would soon take the advice of the scientist and the science fiction writer.

      At the beginning of 1915, when Germany declared the waters around Britain a war zone, U-boats expanded their predatory attacks on commercial shipping. Public outcries against this deadly aggression were heard loud and clear throughout the government. Submarine warfare dominated the suggestions submitted by well-intentioned citizens, who continued to flood the Admiralty with ideas throughout the war. But good intentions were not enough—technology would have to be based on science. The Admiralty staff, however, was preoccupied with strategic planning and day to day decision-making. There was simply no organization tasked to separate ideas with potential from a vast collection of well-meaning but fanciful inventions. Yet, by the spring of 1915, Parliament, as well as the Admiralty, was acutely aware that matching what Germany’s scientific minds had devised required an appropriate response … and quickly.

      The solution came from Arthur James Balfour who was named First Lord of the Admiralty on May 25, 1915, a member of Prime Minister Asquith’s Cabinet, replacing Winston Churchill. On July 5, through Lord Balfour’s urging, two scientific boards were created, one attached directly to the War Office. The other would focus specifically on naval technology—the Board of Invention and Research (BIR). Oversight of the BIR was assigned to Balfour, who fully understood the Admiralty’s urgent need to enlist scientific minds from both industry and academia. His insistence that the Board be free of administrative control by the Admiralty enabled the civilian scientists the flexibility to operate independently.¹²

      Although the BIR would exist outside of direct naval control, the Board’s chairmanship would be best served by a man with extensive naval experience. Balfour then offered former First Sea Lord, Admiral Sir John Fisher, that position. The now retired Fisher, who eagerly