Military history


The British and the Americans in early April finally began to freely discuss technology for breaking naval Enigma. The breakthrough came at an Allied conference in Washington, from April 6 to April 17. The primary purpose of that conference was to unify and integrate the collection and distribution of raw Axis intercepts and the Allied HF/DF networks in the Atlantic and Pacific, but the conferees went far beyond that.

The chief of the British delegation was the old Naval Intelligence Division hand Humphrey R. Sandwith, a captain in the Royal Navy. Since the onset of war, Sandwith had been in charge of upgrading the British intercept (Y Service) and HF/DF networks. The chief American delegates were the recent winners in the bureaucratic battle for control of OP20G, Joseph Redman and Joseph Wenger, reputedly the Navy’s foremost experts in radio communications.

The British, Canadians, and Americans hammered out agreements that did in fact integrate and greatly improve the collection and distribution of raw Axis radio traffic and HF/DF signals. Adding to the British Atlantic HF/DF network, by summer the Americans had in operation four HF/DF stations on the East Coast, equipped with Type DAB receivers. In addition, the Americans established at Sewall, Maine, a “pilot” model of the more sophisticated Type DAJ receiver, which was fully automatic and which produced a bearing on a U-boat transmission nearly instantaneously.

The historian Bradley Smith wrote that in addition to these important advances in electronics, the British chose this forum to describe to the Americans in detail “how the British extracted intelligence from intercepted enemy radio traffic and how they put it into a form that could be used in naval operations.” This included fairly informative disclosures about techniques employed at Bletchley Park, the Admiralty’s OIC, and in the U-boat Tracking Room.

The historian Harry Hinsley wrote, additionally, that the British finally—and unequivocally—promised to give the U.S. Navy Department a “bombe,” in order “to save it the trouble of designing its own machine.” However, Hinsley added, the British were slow to make good on this promise and that as a result of the delay, by June American and British relations “were strained.”

On the heels of this conference, Rodger Winn flew to Washington to urge Admiral King and his senior assistants to create a U-boat Tracking Room similar to and linked with his own. King already had a top secret “War Room” akin to the Admiralty’s OIC but no U-boat Tracking Room, as such. The American version of the OIC, commanded by King’s flag secretary and confidant, George C. Dyer, who limited access to a very few, was known as the Combined Operations and Intelligence Center (COIC).

When Winn met with King to make his case in persuasive and lawyerly fashion, he encountered no difficulties. King readily agreed, and his deputies assigned the submarine tracking task to a Navy captain, Kenneth A. Knowles, who had retired with a physical disability but had returned to active duty after the Pearl Harbor attack.

A great many avenues opened up as a result of these exchanges. But some Americans remained exasperated over what appeared to be the continuing British reluctance to provide them with a bombe and to tackle four-rotor Enigma with allout vigor. Therefore the Americans did not slacken in their secret efforts to design their own version of a bombe. This important work was carried forward by Howard Engstrom, the Yale mathematician and naval reservist. Called to active duty in February with the rank of full lieutenant, Engstrom took command of OP20G’s “Research Section,” and devoted himself full-time to naval Enigma. Within merely four months, he rose another notch in rank to lieutenant-commander, a small tribute to his genius and his progress on a bombe design.

* See Kruh article in Cryptologia, April 1989.

* Hilary P. Jones, Ludlow, Mayrant, Roe, Rowan, Trippe, Wainwright.

 Jacob Jones and Dickerson (damaged at Iceland in January) at New York; Dallas and Upshur at Norfolk. Roe remained until about March 3.

* Many writers have made too much of this resistance to blackouts or dimouts. Only rarely were moon, weather, and tactical conditions such that distant shorelights were advantageous to the very few German U-boats operating in Florida waters. Most civil defense authorities and mayors all over the East Coast opposed blackouts and dimouts. They were said to increase the danger of crime and automobile and truck accidents and to decrease nighttime restaurant dining, nightclubbing, etc., causing economic hardships for a large number of people.

 Track of the Gray Wolf (1988).

* Credited with sinking 25 confirmed ships for 183,223 tons—all on U-96—Lehmann-Willenbrock, who provided the prototypical U-boat skipper for Das Boot, ranked sixth in the war.

 A Type IXD, the largest attack submarine built by the Germans during the war. Conceived to satisfy the advocates of the canceled U-cruisers, the IXD was 35 feet longer (287 versus 252) than the Type IXC and had double the fuel capacity (442 tons), giving it twice the range (24,000 versus 12,000 miles). Like the Type IXC, the IXD was slow-diving and clumsy and was thus unsuitable for attacking escorted convoys. The older onetime flotilla commanders Hans Ibbeken and Ernst Sobe commissioned the first two Type IXDs, U-178 and U-179. Gysae and Ritterkreuz holder Wolfgang Lüth commissioned the next two, U-177 and U-181.

* Outwitting a patrol plane, a light cruiser, and an auxiliary cruiser, Doggerbank laid seventy-five mines off Cape Town on the night of March 12-13. Returning to Cape Town on the night of April 16-17, she laid another eighty mines. Her 155 mines caused temporary chaos in Cape Town, sank two freighters, and damaged three other ships.

 See Plate 12.

 The Lagos refinery on Aruba, which produced 7 million barrels of petroleum products per month, was the largest in the world.

* Dönitz’s reluctance to shell the refineries and tank farms on Aruba and Curaçao—worth far more to the Axis than the tankers U-67 or U-502 might sink—must be regarded as a serious strategic lapse.

* At the time of the award, Clausen’s confirmed score on U-37 and U-129 was nineteen ships for 63,855 tons, including, by error, two Vichy vessels: the submarine Sfax and the small tanker Rhone.

 His departure left eight Ritterkreuz holders engaged in the U-boat war against the Americas: Bigalk, Bleichrodt, Hardegen, Mützelburg, Schnee, Scholtz, Suhren, and Topp.

* In the wake of the Italian group, Emilio Olivieri in Calvi, patrolling alone in the same area and southward to British and Dutch Guiana, sank five ships for 27,571 tons, including three tankers (the Americans T. C. McCobb, 7,500 tons, and E.V.R. Thayer, 7,100 tons, plus the Panamanian Ben Brush, 7,700 tons), bringing the results of the first Italian patrols to the West Indies to twenty ships (nine tankers) sunk for 120,417 tons. However, the Italians sank no more ships in the Atlantic in 1942.

 Some of the January boats sank ships in January, February, and March; some of the February boats sank ships in February. Total sinkings by all U-boats in the month of February only: fifty-nine confirmed ships sunk (twenty-three tankers) for 331,219 tons and nine ships damaged (eight tankers).

* Three British, Inverarder, 5,600 tons; Anadara, 8,000 tons, which was credited in postwar years with sinking U-651; Finnanger, 9,500 tons; and the Norwegian Eidanger, 9,400 tons.

* The Allies equipped 768 merchant ships with net defense. A total of twenty-one ships fitted with nets were attacked by torpedoes during the war. The nets deflected ten attacks, but five ships were damaged and six were sunk.

* Some of the troops were bound for an amphibious assault (Ironclad) on the Vichy French island of Madagascar, to prevent a possible Japanese lodgement, which would pose a grave threat to British shipping in the Indian Ocean.

 At the time of the award, Bauer’s confirmed score was fifteen ships sunk for 62,221 tons.

* Cole, Dahlgren, Dallas, Dickerson, Du Pont, Ellis, Emmons, Greer, Hamilton, Herbert, Macomb, Roper, Tarbell, Upshur.

 The destroyers assigned to convoys AT 12 and TA 12 were at sea on these tasks about thirty-five days, February 19 to March 25. Adding a week for refit and R&R, every destroyer assigned to escort a troop convoy to Europe was tied up about six weeks.

* In keeping with the Navy’s policy of naming some ships after those lost in combat, the new destroyer escort program included a Reuben James and a Jacob Jones.

* At the time of the award, Berlin propagandists declared Ites had sunk 11 ships for over 100,000 tons. His confirmed score on the duck U-146 and U-94 was nine ships for 47,257 tons, plus damage to the 8,000-ton tanker.

* Two American “seaplanes,” probably acting on a DF fix, found and attacked Heyse off Bermuda on March 7, dropping a total of six depth charges. Two were duds; the other four fell wide of the mark.

* At the time of the award, Mohr’s confirmed score was fifteen ships for 64,832 tons, including the light cruiser Dunedin, sunk during the Atlantis-Python rescue.

* No British corvettes arrived in March; only fourteen British trawlers were ready for duty on April 1.

 To March 1, 1942, all the U-boats assigned to the campaign in the Americas had sunk forty-five tankers and damaged thirteen. Eighteen of the forty-five were sunk in the waters of the Eastern Sea Frontier, eleven in the Caribbean, and sixteen elsewhere. (See Appendix 17.)

 Moreover, on February 26, Andrews reported to King that the trawlers were “not satisfactory escorts.”

* Naval authorities were considering seven days, not eight.

* Earlier, Roosevelt wrote Churchill that “I have always held destroyers should not be used [for] coast patrol as they are all-purpose ships.” Few in the Navy quarreled with that view, but King and most senior officers argued that coastal convoys required, at minimum, destroyer escorts (or frigates), which had the necessary seaworthiness, range, endurance, and firepower.

 King to Ingersoll, information to NSHQ, Ottawa, March 20 at 1305 and 1310 hours.

* Halifax-Boston convoys were designated XB; Boston-Halifax convoys, BX.

 Including Task Force 39 (99), comprised of the new battleship Washington, carrier Wasp, cruisers Wichita and Tuscaloosa, and six destroyers temporarily at Scapa Flow, the U.S. Navy earmarked altogether about twenty warships specifically to counter a sortie of Tirpitz et al.: two carriers, two new battleships, four heavy cruisers, a light cruiser, and about ten destroyers.

* Plus other Atlantic Fleet Catalinas, based at Norfolk, temporarily on loan. The 82 Navy aircraft included 15 of 70 Vought OS2U Kingfisher scout seaplanes that were diverted from delivery to the British and were manned by Coast Guard aircrews.

 The canal could accommodate ships drawing up to 25 feet and up to 500 feet in length. Most loaded northbound tankers drew too much water to use the canal, but all southbound tankers (in ballast and drawing less water) of 500 feet in length or less were required to go that way.

* Public Records Office (PRO), Kew, “Control of Shipping in West Atlantic During U-boat Campaign. January-June 1942.” Document ADM 205/21, pp. 1-10.

 The same agreement gave Admiral Hoover of the Caribbean Sea Frontier operational control of the Army Air Forces’s fifty-plane Antilles Air Task Force.

* Ellyson, Emmons, Hambleton, Macomb, Rodman.

 Over Roosevelt’s signature, King pointedly asked Churchill why the Admiralty could not use the British carrier Furious, departing the United States on April 3, for this purpose.

* En route to the British Isles with convoy QP 11, Edinburgh went down with close to six tons of gold in 465 ingots of twenty-six pounds each. Most of the gold (payment to the Americans for war supplies) was recovered by British divers in 1981 and split with the Soviets.

 The commander of Task Force 99, Robert C. Giffen, wrote King that British destroyers “used bad technique” in heavy fog at 18 knots and that his battleship, Washington, had a “close call” in this mishap, nearly colliding with the British destroyer Martin. Incidents of this kind reinforced King’s conviction that American and British naval forces should not be “mixed.”

* The other carrier in the Pacific, Saratoga, torpedoed by a Japanese submarine on January 11, 1942, and repaired on the West Coast, was still in workup.

 Forces on Bataan surrendered April 9 and those on Corregidor, May 6.

 Broome, Decatur, Dickerson, Du Pont, Herbert, MacLeish, McCormick, Roper, and the miscellaneous auxiliary Semmes.

Fury, Impulse, Ready, Restless, and Temptress.

* The Type XIV U-tankers, affectionately known as Milchkuhs (Milk Cows), were indeed bovine: 220 feet in length, 31 feet shorter than a Type IX, with bulbous external saddle fuel tanks, which gave the boat a surface displacement of nearly 1,700 tons. The Milk Cow had a fuel-oil capacity of about 650 tons—about 200 tons for its own use and 450 tons for its “customers.” Its crew of 53 included a doctor. It was lightly armed for defense: no torpedo tubes; antiaircraft guns on the bridge. Apart from its slow surface speed and clumsiness while submerged, the chief drawback of the Type XIV was that it had no room below to carry torpedoes for its “customers”; four were carried in deck canisters.

* Bristol, Broome, Buchanan, Cole, Dallas, Dickerson, Du Pont, Edison, Ellis, Emmons, Greer, Hambleton, Hamilton, Herbert, Lea, MacLeish, Macomb, Nicholson, Noa, Roper, Semmes, Swanson, Woolsey.

* Hardegen’s confirmed score on the duck U-147 and U-123 was twenty-three ships for 132,081 tons, not counting the two unidentified ships usually credited on his first patrol to America but counting the two sunk but salvaged tankers, Oklahoma and Esso Baton Rouge.

 Panamanians Heinrich von Riedemann, 11,000 tons, and H. G. Seidel, 10,400 tons; Norwegian Sandar, 7,600 tons; and the Dutch Amsterdam, 7,300 tons.

 At the time of the award, April 23, Zapp’s confirmed score was thirteen ships for 80,014 tons. By the end of the patrol, it stood at fifteen ships for 103,495 tons.

* Three Americans: B. T. Benson, 8,000 tons; Atlas, 7,100 tons; Tamaulipas, 7,000 tons; and the British Splendor, 7,100 tons.

* To fulfill this need, in the fall of 1941 Dönitz and the OKM had ordered the conversion of four Type VIICs (U-1059 to U-1062) to torpedo-supply boats, designated Type VIIF. Similar in length (254 feet) and shape to the Type VIID minelayer, the VIIF had a torpedo-storage compartment inserted between the control room and engine room that had space for twenty-four torpedoes, in addition to the boat’s own internal load. Pending the arrival of the VIIFs (in 1943), two captured Dutch boats (commissioned U-D3 and U-D5) were converted to torpedo-supply boats. However, the conversions were begun too late for the campaign in the Americas.

 Berlin propagandists credited Topp with sinking 31 ships for 208,000 tons, including a destroyer and an “escort.” At the time of the award, his confirmed score on the duck U-57 and U-552 was 28 ships for about 163,000 tons, including the American destroyer Reuben James and the 227-ton British ASW trawler Commander Horton.

* A doubtful conclusion, probably influenced by Allied propaganda depicting German submariners as fanatical, mad-dog Nazi killers. No rational U-boat skipper would engage in a surface gun battle with a destroyer, which had the advantage in firepower, gun armor, and speed to ram, as well as the ability to call in aircraft and other ASW forces.

* Several days earlier, April 11, one of the British ASW trawlers, St. Cathan, was accidentally rammed and sunk by a merchant ship off North Carolina, leaving twenty-two.

 Many sport divers, including Roger A. Warden and Homer H. Hickam, Jr., author of Torpedo Junction, routinely dive on U-85. They dispute the Navy’s report in one instance: they found evidence that one of Roper’s 3/50 caliber guns registered a hit on the sub, just abaft the conning tower. They also say there is a G7a (air) torpedo in a topside canister. Warden writes that in 1997 a diver found a box containing three Enigma rotors.

* In addition to the six S-class submarines, the U.S. Navy in early 1942 loaned the British three R-class boats for use in ASW training. The Canadian minesweeper Georgian accidentally rammed and sank R-19, renamed P-514, off Cape Race.

* In addition to the six S-class submarines, the U.S. Navy in early 1942 loaned the British three R-class boats for use in ASW training. The Canadian minesweeper Georgian accidentally rammed and sank R-19, renamed P-514, off Cape Race.

* See Appendix 5.

* Kelbling reported that an escort fixed his boat with a “bright red light” at a range of 4,000 yards and “accurate” gunfire followed at a range of 2,000 yards. Kerneval speculated that the light might be “infrared rays,” until it was informed, to the staff’s chagrin, that such rays were invisible. The matter was finally dismissed as “probably a colored searchlight,” but in the flap over the light, the “accurate gunfire” at 2,000 yards in total darkness—an almost certain indication that the escorts were equipped with miniaturized, highly sensitive, and accurate radar—was overlooked. Assured by the technical services that escorts were not large enough to carry effective radar, Kerneval continued to accept that brass-bound judgment as reliable.

 The agent, who has not been identified in published sources, was put ashore on the north coast of Iceland on or about April 7. Presumably his mission was to report Allied ship sailings.

* See Appendix 2.

 See Appendix 6.

* Leaving twenty Type VIIs in the Mediterranean U-boat force on April 1, 1942. Between January 5 and March 18, 1942, British submarines sank five Italian submarines in the Mediterranean. Unbeaten, which earlier sank U-374, got one; Upholder got two; Ultimatum and Thorn, one each.

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