HUFF DUFF
Many authorities have asserted that in World War II, land and shipboard high-frequency direction finding (HF/DF or Huff Duff) should rank right up with radar and codebreaking as an anti-U-boat weapon.
Until recently, little was known about Huff Duff and its evolution. Historian Kathleen Broome Williams admirably filled that gap in 1996 with the publication of her book Secret Weapon: U.S. High-Frequency Direction Finding in the Battle of the Atlantic. The following is condensed from her book.
In the 1930s, scientists and engineers in a number of countries secretly developed electronic devices for the specific purpose of taking a bearing on the transmissions of radio traffic in the high-frequency ranges. The military establishments were especially interested in a device capable of nearly instantaneous detection of the new, extremely brief transmissions of German U-boats that were manifest in their prewar exercises and operations.
In several nations, soon to become allies against the Axis, engineers produced Huff Duff devices, albeit slowly.
In Great Britain, the R&D on land and shipboard Huff Duff proceeded under the direction of Robert Watson-Watt, the so-called father of radar. The first British version for shipboard use, FH 1, was installed on the destroyer Hesperus on March 12, 1940, and later that year on a few other convoy escorts and rescue ships. Owing to topside stability problems and electronic interferences, in the early stages of development it was not possible to fit both radar and Huff Duff on the same ship. Inasmuch as British warship captains preferred radar over the less reliable Huff Duff, the latter had a lower R&D priority, and development lagged.
Slowly, British engineers produced improved Huff Duff models FH 2 and FH 3. In October 1941, the FH 3 was first installed on the ex-American Coast Guard cutter Mendota, serving in the Royal Navy as the sloop Culver, along with Type 271 centimetric-wavelength radar. Culver sailed as an escort to West Africa. On the return voyage, as an escort in convoy Sierra Leone 98, Culver was sunk on January 31, 1942, by U-105, a calamity that did nothing to build confidence in Huff Duff.1
By that time, according to Williams, about twenty-five convoy escorts and rescue vessels were fitted with British FH 3 Huff Duff sets. In March 1942, yet another improved model, FH 4, was fitted on the ex-American destroyer Twiggs, serving in the Royal Navy as Leamington. This set performed better, and the Admiralty ordered a total of thirty FH 4s for delivery by the end of the year. By August 1942, seventy Royal Navy vessels were fitted with Huff Duff, mostly FH 3s. It was not until mid-1943 that shipboard Huff Duff sets were commonplace in the Royal Navy, and they were still very much hush-hush. 2
In France, prewar R&D on Huff Duff was carried out at the Laboratoire Téléphonique in Paris, a subsidiary of International Telephone and Telegraph (ITT). Maurice E. Deloraine was the director of the lab; Henri Busignies was the leading expert on Huff Duff. This work paralleled that of the British, with whom the French shared electronic secrets until the Germans overran France in May 1940.
By that time, Busignies had built four Huff Duff models that were approximately the equivalent of the British FH 3s. They were automatic and “instantaneous,” fitted with a cathode-ray tube on which a lingering “blip” was displayed, like a radar set. The antenna, based on the universally used Adcock, incorporated a “sense” feature, developed by the Pole W. Struszynski, that distinguished between the actual signal bearing and its reciprocal echo, a breakthrough of transcendent importance. The invading Germans insisted that ITT keep the Paris lab going, but Deloraine, Busignies, and nine other top engineers destroyed the Huff Duff sets and fled with their families to Lisbon with Huff Duff drawings and some key components. These French boarded an American tramp steamer, Siboney, and reached Hobo-ken, New Jersey, on December 31, 1940.
The president of ITT, Sosthenes Behn, directed these French engineers to join ITT’s New York lab, then arranged a meeting between Deloraine and Busignies and representatives of the U.S. Army and Navy. The Americans were distrustful of Behn and ITT because of its business ties to the Germans and refused to give ITT or the French an unlimited security clearance. However, Maxwell K. Goldstein, the U.S. Navy’s Huff Duff expert at the Naval Research Laboratory, already embarked on creating a chain of Atlantic shore-based Huff Duff stations, immediately recognized the advantages of the Busignies design, and the Navy (but not the Army) gave ITT and the Frenchmen a “limited” security clearance and a contract to build four Busignies Huff Duff sets for shipboard use.
The U.S. Navy, experimenting with its own shipboard Huff Duff models as well as the British FH 3s, was slow to embrace the Busignies Huff Duff. Like the British, American warship captains preferred radar over Huff Duff. That preference, plus the distrust of ITT’s loyalty and the withholding of full security clearances for the French engineers, delayed the development of Huff Duff in the United States for months. Tests on the four Busignies sets did not take place until October 1941. Moreover, the reviews were not raves.
Finally, in May 1942, the U.S. Navy embraced Huff Duff. Maxwell Goldstein carried out comparative tests on the new destroyer Corry, fitted with both the British FH 3 and the Busignies model, designated DAQ to distinguish it from the DAJ sets in its shore-based system. Williams wrote that Goldstein chose the DAQ over the British FH 3 and that on June 26, 1942, Admiral King ordered half of all new U.S. destroyers and destroyer escorts to be fitted with DAQs or any improved models. Altogether, Williams wrote, ITT produced about four thousand Huff Duff sets for the U.S. military in World War II. The U.S. Navy presented ITT president Sosthenes Behn and the ITT company high awards. The Americans also awarded Deloraine and Busignies Certificates of Commendation “for outstanding service” in the Allied cause but never granted them unrestricted security clearances.
The popular rush to credit radar, and later codebreaking, for the defeat of the U-boat left the equally effective but less glamorous and more difficult to understand Huff Duff in the shadows.
1. See Volume I, pp. 475-77 and p. 497.
2. As usual, the Canadians were last to receive Huff Duff in quantity. In 1942, the destroyer Restigouche was the first Canadian warship to be fitted with a Huff Duff set. It was said to have been “scrounged” by her captain from a British shipyard.