Military history


In mid-April there were nine U-boats in the North Atlantic hunting grounds. Six patrolled a line well southwest of Iceland. Two patrolled directly south of Iceland. A new VIIB, U-75, commanded by Helmuth Ringelmann, age twenty-nine, was westbound through the Northwest Approaches. Three of the eight boats were low on fuel and poised to return to France; three others, including a new VIIC, U-553, commanded by Karl Thurmann, age thirty-one, sailed to replace them. However, U-553 was compelled to abort to Bergen with engine problems.

The hunting in these distant western waters was disastrously poor. In the three-week period April 4 to April 25, the boats attacked no convoys. In the two-week period April 10 to April 25, only three boats had successes: Otto Salmann in U-52 (two ships for 14,000 tons), Helmut Rosenbaum in U-73 (one ship for 8,600 tons), and Karl-Heinz Moehle in U-123 (one ship for 7,300 tons).

One of the ships sunk by Salmann in U-52 was the 6,600-ton Dutch freighter Saleir, an empty straggler from convoy Outbound 306. She went down on April 10 near 31 degrees west. As it happened, a new (1940) American destroyer of the Argentia-based American Support Force, Niblack, commanded by Edward R. Durgin, was close by on a reconnaissance patrol. Durgin rescued three boatloads of survivors and while doing so, his sonar operator reported contact on a U-boat. Durgin went to battle stations and drove off the U-boat with three depth charges. According to Niblack’s official history, “This bloodless battle apparently was the first action between American and German forces in World War II.”*

The complete absence of convoy contacts aroused suspicion in Kerneval. Dönitz became convinced there must be a spy in the German or Italian armed forces giving away U-boat positions. He imposed drastic new restrictions on the number of people at Kerneval, Bordeaux, Berlin, and elsewhere who were authorized to know the position of U-boats, or to tune in on U-boat radio traffic. At his request, Admiral Raeder sent the following tough message to all Kriegsmarine commands:

The U-boat campaign makes it necessary to restrict severely the reading of signals by unauthorized persons. Once again I forbid all authorities who have not express orders from the operations division or the admiral commanding U-boats to tune in on the operational U-boat [radio] wave. I shall in the future consider all transgressions of this order as a criminal act endangering national security.

It also occurred to Dönitz that the British had possibly improved DFing and—inconceivable as it seemed—broken the naval Enigma. He therefore ordered the boats to maintain strict radio silence, except when reporting weather or convoy contacts, and requested the OKM to introduce “a new U-boat cipher.” The OKM, Dönitz logged, “approved” his request for a new cipher, but putting it into service was to take a long time.

Dönitz was correct on both counts. The British had improved DFing and, no less important, the processing of DF information. Moreover, commencing April 22, the codebreakers at Bletchley Park, utilizing the material captured from the Krebs in the Norway raid and “cryptanalytical methods,” broke “the whole of the [Enigma] traffic of April 1941,” the official historian wrote. Hence Rodger Winn in the U-boat Tracking Room of the O.I.C. was privy to all U-boat traffic for the months of February (previously broken) and April. That traffic, plus traffic from the hand cipher Werft, provided him with a complete picture of U-boat operations for those two months, including Dönitz’s decision to shift the boats out of the Northwest Approaches to the waters west of Iceland.

From the February and April Enigma traffic, Bletchley Park learned for the first time that the Kriegsmarine maintained a fleet of eight trawlers in the Atlantic for weather reporting. At least two of the trawlers were at sea at any given time, one north of Iceland, one in mid-Atlantic. The trawlers carried naval Enigma. They broadcast weather reports in a special cipher, Wetterkruzschlüssel, and also carried “short signal” books. A naval officer at Bletchley Park, Harry Hinsley (later the distinguished historian of British intelligence), suggested that the Admiralty attempt to capture one of these trawlers at the earliest possible date to gain more Enigma keys and material.

The Admiralty looked upon this suggestion favorably and commenced drawing plans. This proposed capture “at sea” was not out of the ordinary. Over a year prior, the commander of the Home Fleet, Charles Forbes, had urged all light Royal Navy vessels to form a “boarding party” for the purpose of capturing a U-boat. His advisory on how to go about this was a bit ferocious and hardly in keeping with the humane customs of the sea.

The first and overriding objective was, of course, to prevent the U-boat crew from scuttling the boat by opening the ballast-tank vents or by setting demolition charges and then jumping overboard. This objective might be achieved, Forbes suggested, by trapping Germans belowdecks, thus forcing them to close the vents or defuse the charges in order to preserve their own lives. The prospective British captors, Forbes went on, should therefore come up to the surfaced U-boat at full speed and open fire with Lewis machine guns at the personnel as they came up through the conning-tower hatch and appeared on the bridge. “The object will be most effectively achieved,” Forbes continued callously, “if a body gets jammed in the mouth of the hatch at an early stage.” Those Germans already up and clear of the hatch and who did not appear to be taking hostile action were to be spared and captured, except those seen to be throwing papers overboard. Machine gunners should “open immediate and effective fire” on those particular Germans, Forbes said, advancing a policy that was tantamount to murder.

The next step was to put a small, armed party on the deck of the U-boat. The boarding party was to evacuate “all the officers and most of the men” from the U-boat to prevent them from diving the vessel and escaping. The party was to leave “two or three of the crew” belowdecks and keep them there “continuously” under supervision to ensure that no live demolition charges were in place and to get the boat shipshape. If all Germans had already left the boat, “one or more of the crew should be forced to reenter it” for the same purpose.

Frustrated by the lack of successes on the North Atlantic run and believing that he might have overreacted to the British ASW threat, in the waning days of April Dönitz shifted the bulk of the North Atlantic U-boat force eastward toward the British Isles. Late on the afternoon of April 27, Erich Topp in U-552 found a big target at about 17 degrees west longitude: the 10,100-ton British freighter Beacon Grange, sailing alone. Topp attacked submerged, firing all four bow tubes. The ship went down; the crew broadcast the submarine alarm, SSS, then took to the lifeboats.

Nine hours later, April 28, Karl-Heinz Moehle in U-123 found convoy Halifax 121 at about 17 degrees west. It was composed of forty-seven ships and was guarded by nine escorts. The convoy offered the Germans in that area the first opportunity in almost four weeks to mount another pack attack. Dönitz instructed Moehle to shadow and broadcast beacons, so the other boats in the area and Condors from France and Norway could converge.

The British DFed Moehle’s shadow reports and warned the convoy commander as well as the commander of convoy Outbound 314, which was passing close by on a westerly course. The warning helped some. The escorts attempted to drive Moehle off for good, but he hung on tenaciously, regaining contact at dawn. The Condors failed to locate the convoy and the escorts forced Moehle off again and he lost contact, but three other boats made contact with it later in the day.

The convoy commander was fully aware that U-boats were converging, but he did not expect an attack before dark. Erich Topp in U-552, who had submerged ahead of the convoy, did not wait. In mid-afternoon, he let the lead escorts pass, then fired at the 8,200-ton British tanker Capulet. Some torpedoes hit, wrecking the ship, but it did not sink. Admiralty intelligence noted later that this was the first daylight attack by a submerged U-boat on a fully escorted convoy since the summer of 1940. Later, some ASW experts speculated that in view of the strengthened convoy escort and the coming of short nights, all the U-boats in the northern area might revert to strictly daylight submerged attacks.

The escorts counterattacked. Two destroyers, Maori and Inglefield, found U-552 on sonar and delivered five depth-charge attacks. These held Topp down for hours while the convoy proceeded and, as a result, Topp was unable to mount a second attack. Meanwhile, three escorts from convoy Outbound 314 joined convoy Halifax 121, raising the total escorts to twelve. One of the joining escorts, the destroyer Douglas, attempted to sink the wrecked tanker Capulet by gunfire, but failed, then joined in the U-boat hunt.

After dark Lehmann-Willenbrock in U-96 broadcast another position report, then attacked on the surface. In a well-aimed salvo of four bow torpedoes, he sank three big loaded ships: the 8,500-ton British tanker Oilfield, the 9,900-ton Norwegian tanker Caledonia, and the 8,900-ton British freighter Port Hardy. The Oilfield burst into flames which lit up the scene and forced Lehmann-Willenbrock to dive, losing an opportunity for a second attack. All three ships, totaling 27,300 tons, sank.

The twelve escorts hunted relentlessly. The corvette Gladiolus got a sonar contact and dropped ten depth charges. Joined by two ex-American four-stack destroyers from convoy Outbound 314, Leamington and Roxborough, the three ships carried out four further depth-charge attacks. The other newly arrived escort, the British destroyer Douglas, delivered a punishing depth-charge attack on what proved to be IXB U-65, under a new skipper, Joachim Hoppe, age twenty-six, who had commanded the boat merely sixteen days and had not yet fired any torpedoes. The attack destroyed U-65. There were no survivors. She was the seventh U-boat lost in the waters of the Northwest Approaches in as many weeks.

Dönitz made every conceivable effort to mount continuing attacks on Halifax 121 by U-boat and Condor, but the British cleverly routed the convoy away from the boats and all efforts to find it again failed. In total, four boats had made contact. Two boats had shot torpedoes which had resulted in the sinking or destruction of four ships, three of them loaded tankers. That was a blow, but the other forty-three ships of convoy Halifax 121 reached port safely.

On the day after the attack, April 29, the corvette Gladiolus was detached from the convoy to rescue survivors of the freighter Beacon Grange, sunk by U-552 two days earlier. Directed to the lifeboats by a Sunderland, Gladiolus picked up forty-one men. After the last man came aboard, Gladiolus saw a puff of smoke on the horizon. Racing toward it at full speed, Gladiolus spotted the conning tower of a U-boat and what was described as a “kite” flying above the boat. Gladiolus came up but the boat (and “kite”) disappeared beneath the sea. Gladiolus got sonar contact and made three attacks, dropping thirty-one depth charges. These brought up a large air bubble and an inflatable life raft, which, however, sank or disappeared before it could be recovered. Gladiolusproudly claimed a kill, but no U-boat was lost on this day.*

During April, 307 loaded ships sailed in convoys from Halifax to the British Isles. German U-boats sank sixteen vessels (five tankers) from these convoys—eleven from Slow Convoy 26, four from convoy Halifax 121, and a small straggler from Halifax 117. Besides that, the oceangoing U-boats sank eleven other ships (one tanker) for about 70,000 tons, which were sailing alone per the new policy that allowed ships of 12 knots or faster to go it alone. Total sinkings by U-boats in the North Atlantic area in April therefore came to twenty-seven. In return, two U-boats, U-65 and U-76, had been lost. As before, the very great successes of the U-boats in the waters off West Africa tended to obscure the lean convoy hunting on the North Atlantic run.

At this time, Dönitz confronted yet another possible diminution of the Atlantic U-boat force. Berlin war planners suggested that U-boats should be sent to the eastern Mediterranean and Aegean seas to support German ground forces in Greece and North Africa. The boats were to operate against British naval and merchant shipping, which was evacuating British forces from Greece to Crete and to North Africa, and resupplying the British in those places, as well as British forces in Palestine.

Since this suggestion appealed to Hitler and his senior advisers, Admiral Raeder and Dönitz had to mount a major campaign to kill it. Meeting with Hitler on April 20, Raeder argued that the plan was not advisable because, first, it would divert U-boats from the decisive North Atlantic battleground where Dönitz had a total force of but thirty boats, of which barely eight to ten were in the hunting grounds at any given time; second, because the confined Mediterranean was a dangerous place for submarine operations and only the most experienced skippers and crews could be sent there, robbing the North Atlantic force of its most productive boats; and third, because a U-boat base would have to be created in Italy or Yugoslavia, draining scarce submarine technicians from France or Germany.

In place of German boats, Raeder suggested, Berlin should propose to Rome that the Bordeaux-based Italian boats operating unproductively in the Atlantic be withdrawn and sent to the eastern Mediterranean. The stenographer recorded that Hitler roundly approved this proposal: “The Führer is in complete agreement with the decision not to send German submarines into the Mediterranean, likewise with the withdrawal of Italian submarines from the Atlantic.” When he heard the news, Dönitz rejoiced. But the idea of sending German U-boats to the Mediterranean in support of German ground forces was not as dead as he thought.

By then, as related, four Bordeaux-based Italian submarines had been lost in the North Atlantic, leaving a net force of twenty-three. Most of these now patrolled southward to the Azores or beyond to West African waters. Four medium boats fleeing the Red Sea (via the Cape of Good Hope) were to join the Bordeaux force in May. Under the recall plan, ten boats were to commence the return to Italy in June. In nine months of operations to May 1, 1941, all Atlantic-based Italian submarines had positively sunk thirty-three ships (including five neutrals and a ship shared with U-38 and a ship shared with U-107), and had severely damaged the Canadian destroyer Saguenay.*

The U-boat campaign in the decisive North Atlantic area in the winter of 1940-1941 fell well short of what the Germans had expected. The U-boats sailing to that area in the five months from December 1 to May 1 sank only about 125 merchant ships for about 752,658 tons. This was an average of about 150,500 tons a month, sharply less than the monthly average attained in the “Happy Time,” May through November, 1940. Patrols to the South Atlantic area raised the total sinkings substantially, disguising the declining results in the north. The patrols to the south added about sixty-five ships for about 364,215 tons, raising the total of sinkings by all U-boats sailing in that five-month period to 194 ships for about 1.1 million tons. British shipyards in that same period produced less than half that tonnage, but the total loss was more than made up by the return to service of nearly 1 million gross tons of damaged shipping that had been idled in British shipyards.

London continued to bemoan loudly the loss of tankers but in fact, the tanker losses in that five months were not overwhelming: twenty-seven ships for about 231,500 tons. Twenty-three of these tankers were lost in the North Atlantic; four in the South Atlantic. Of the total, twenty were British-owned; six were foreign ships on charter, and one was the Vichy French Rhone, sunk in error. Owing to the construction of new tankers in British yards, and to various Lend-Lease measures to supply American and foreign tankers to the British, and to the participation of American ships in the Caribbean-East Coast “shuttle,” the oft-predicted oil crisis in the British Isles did not yet occur, according to the official British oil historian, D. J. Payton-Smith.

It was not yet apparent, but by the end of April 1941, the Battle of the Atlantic in northern waters had turned slightly in favor of the British, at least for the nonce. Under operational control of the Admiralty, Coastal Command had built air bases in Iceland and the Faeroes, extending daytime air escort of inbound and outbound convoys ever westward. No Coastal Command aircraft had yet sunk a U-boat unassisted, but the increased air coverage gave warning of U-boats to the convoy surface escorts, drove the U-boats off, and held them down, frustrating shadowers and the assembly of packs. The Escort Groups shuttling between the British Isles and Iceland, and those based at Iceland, likewise presented a menacing obstacle. With increasing numbers of escorts available, it was now possible to detach one or more warships to hunt and drive off the convoy shadower and to counterattack and hold down the attacking U-boats, preventing a second attack while the convoy evasively altered course. Inasmuch as U-boats avoided rather than attacked enemy air and surface escorts, with each passing month the escort crews gained more experience and skill in U-boat hunting, while the experience and skill of the U-boat crews declined, a trend that was certain to continue unless the Germans found some means of attacking the escorts.

More difficulties lay ahead for the U-boats. The British had penetrated naval Enigma. Should the Admiralty’s other planned captures succeed, Bletchley Park, employing increased numbers of Turing-Welchman bombes, stood a good chance of a really decisive break into naval Enigma. The number of primitive (but useful) 1.5-meter-wavelength radar sets in Coastal Command aircraft and surface escorts was steadily increasing. New electronic devices were nearly ready for mass production: the greatly improved centimetric-wavelength radar for aircraft and surface vessels, employing the Randall and Boot cavity magnetron; miniaturized High Frequency Direction Finding (HF/DF, or Huff Duff) sets, suitable for installation on convoy vessels, enabling them to home on high-frequency radio transmissions from nearby U-boats*; and greatly improved radio gear for communications between the surface escorts (Talk Between Ships, or TBS) and between the surface escorts and air escorts, the latter an important advance usually overlooked in accounts of the U-boat war.

Week by week the United States had become more deeply involved in the Battle of the Atlantic. In addition to the measures already described, on April 18 Atlantic Fleet commander Ernest King grandly declared that the waters of the “Western Hemisphere,” for which he was responsible, now extended eastward to approximately 26 degrees west longitude (a line just west of Iceland and south to the Azores) and stated in effect that any transgression of that line by the Axis powers would be viewed as “unfriendly.”

In response to requests (read directives from London, the Canadians, too, were poised to enter the Battle of the Atlantic for the first time in an important way. Pending the arrival of the destroyers of the American Support Force, the Canadians were to assume responsibility for convoy escort in Atlantic home waters and out to 35 degrees west, where the spliced-in Iceland-based British escort groups took over the convoys. For this purpose, the Canadians established the Newfoundland Escort Force, some thirty-eight warships,* commanded by a Canadian, L. W. Murray, based at St. John’s. It was supported by twenty-four American-built aircraft in two squadrons of the Canadian Eastern Air Command.

Since improved British ASW measures in the Northwest Approaches made it necessary to again operate the Type VIIs ever farther westward, incurring the penalties imposed by fuel limitations, Dönitz needed far more U-boats to regain the upper hand than he or anyone had ever envisioned. Not just 300, but perhaps twice that number. U-boat production was increasing dramatically: Forty-three new boats were commissioned in the four-month period January-April 1941, but owing to the usual four months required for workup, these were not to reach the Atlantic in substantial numbers until June and beyond. Even assuming modest combat losses and a maximum production rate, rising to twenty or more boats per month in the second half of 1941, by the beginning of 1942 Dönitz could expect to have no more than about 100 oceangoing boats of all types for Atlantic operations.

Given the accelerating rate of aircraft, escort, and ship production in Great Britain, Canada, and the United States, the late-starting and lagging U-boat production, and ever-declining experience levels of U-boat crews, Dönitz was to be hard-pressed to regain the upper hand in the Battle of the Atlantic by 1943 or ever. And yet there was not the slightest sense of defeat among the staff at Kerneval. Even discounting the skipper overclaims, it was clear that the small U-boat arm was causing terror and significant harm to British maritime assets and forcing a great expenditure of Allied resources to counter the threat. Convoying alone—as Churchill repeatedly lamented—had reduced Great Britain’s imports by “one-third.” It was not actually that bad, but bad enough.

* The normal workup period at that time for a new boat was about four months.

* Three of the sinkings were awkward “mistakes”: a Spanish trawler, the 2,800-ton Vichy tanker Rhone, and—worst of all—the 1,400-ton Vichy submarine Sfax.

* His confirmed score was thirty-seven ships for 155,882 tons.

* Remarkably, all eighteen skippers who had won the Ritterkreuz to then were still alive: Prien, Kretschmer, Lüth, and Schütze on leave from their boats in Lorient; Schepke and Endrass on leave from their boats in Germany; Rollmann, Schuhart, Frauenheim, Rösing, Kuhnke, and Oehrn in staff or training jobs; Hartmann, Lemp, and Bleichrodt fitting out new boats in Germany; Jenisch in a British POW camp. Herbert Schultze, hospitalized after Norway, had returned to command of U-48, which was undergoing overhaul in Germany.

 His confirmed total, including Champlain, was twelve ships for 87,278 tons.

* Lend-Lease was signed into law on March 11, 1941. Designed primarily to help Great Britain, which had run out of gold and credits, by war’s end American outlays for Lend-Lease totaled $50.6 billion, of which $31 billion went to Britain.

* The main element of the Support Force was Task Force 4, later redesignated Task Force 24.

* The PBY Catalina was a twin-engine flying boat, designated Patrol Bomber (PB), built by Consolidated (Y). Combat radius: 600 miles at 103 knots. Bomb load: 4,000 pounds.

 See Appendix 10.

* Beginning in the 1980s, a crop of Canadian military and naval historians has worked diligently—and successfully—to correct the record. See Bibliography: Douglas, Hadley, Lund, Milner, Sarty, Steury, et al.

* Simultaneously, British yards were in process of converting a 467-foot, 5,600-ton German-built prize, Hannover, into the “jeep” carrier H.M.S. Audacity, which could carry six fighters. Long Island and Audacity were commissioned in June; Archer in November 1941.

* In tests, Orchis picked up a surfaced submarine at 5,000 yards, a trimmed-down submarine at 2,800 yards, and—remarkably—an eight-foot-high submarine periscope at 1,300 yards (two thirds of a nautical mile).

* Circular torpedo runs, caused by a malfunctioning gyro or stuck rudder, were experienced by submarines of all navies. It is believed that many submarines that disappeared on patrol for “unknown” reasons were the victims of their own torpedoes.

* Endrass’s U-46 and five new boats rushed from Kiel to Helgoland to escape the Baltic ice. Several new oceangoing boats and a number of school ducks were trapped by ice, frozen at dockside until late March.

* Following Hipper’s convoy attack on Christmas Day, the Admiralty had again assigned battleships and submarines to escort these important ocean convoys: the British tender Forth and eight submarines, based at Halifax for this arduous duty, joined by the Free French monster submarine Surcouf.

* These three kills brought Clausen’s total confirmed sinkings on U-37 to ten ships for 16,000 tons in about two months. All the ships were small, averaging 1,600 tons.

* Originally the Admiralty credited a Sunderland of Coastal Command Squadron 210 with the kill on Marcello on January 6, 1941. In a postwar reassessment, credit went to Montgomery.

* Lehmann-Willenbrock’s confirmed score for the patrol was six and a half ships for 44,232 tons, raising his total confirmed score to thirteen and a half ships for 110,322 tons. Including his sinkings on the duck U-20, Moehle’s confirmed score was eighteen and a half ships for 77,310 tons.

* The “old” battleships (1917-1919) capable of carrying out this task were the three on transfer from the Pacific Fleet (Idaho, Mississippi, New Mexico). The new 35,000-ton Treaty battleships, North Carolina and Washington, were commissioned April 9 and May 15, respectively. Two aircraft carriers, Ranger (1934) and Yorktown (1937), could provide additional scouting and firepower. The new carrier Hornet was commissioned on October 20, 1941.

* Bianchi claimed sinking four ships for 26,800 tons on this patrol, plus a possible hit on another of 7,800 tons. This was an Italian record that stood for some time—and is still credited in some Italian accounts of the war. Jürgen Rohwer credits Giovannini with three ships for 14,705 tons.

 Heavy cruiser Hipper; “pocket” battleship Admiral Scheer; battle cruisers Gneisenau and Scharnhorst; merchant-ship raiders Atlantis, Kormoran, Orion, Penquin, Thor (each with six 5.9” guns and four torpedo tubes), plus a possible hit on the 5,400-ton British “boarding vessel” Manistee, sunk by Hessler in U-102.

* The Army’s Abraham Sinkov and Leo Rosen; the Navy’s Prescott H. Currier and Robert H. Weeks. The Army’s legendary codebreaker William F. Friedman was scheduled to head up the party, but after his successful attack on Purple, he had suffered a nervous collapse.

 The Ultra-Magic Deals (1993).

* See writings of Clarke, Denniston, Hinsley, Morris, Welchman, as well as numerous secondary sources.

* Seizing the Enigma (1991).

 The Ultra Americans (1986).

* From the President, a coveted Distinguished Service Medal, stressing his “brilliant skill and initiative … his outstanding professional judgment, astute planning and uncompromising devotion to the fulfillment of an exacting assignment.” From British ambassador Halifax on behalf of King George VI, an Order of the British Empire, praising Engstrom’s “exceptional character and genius.”

 In addition, the aircraft tender Pegasus, which Prien missed in Scapa Flow, and four other warships fitted with catapults patrolled as hunter-killer vessels in the Condor zones of operations.

* The 2.6 million gross tons translates to about 520 ships of 5,000 gross tons. Remarkably, British shipyards more than doubled the goal, sending 975,000 gross tons (the equivalent of 195 ships of 5,000 gross tons) back to sea by July 31, reducing the idled, damaged shipping to about 1.6 million gross tons.

 Very Special Intelligence (1977) and Very Special Admiral: The Life of J. H. Godfrey (1980).

* The Central Blue (1956).

 The Cruel Sea (1951).

* The four boats that attacked the convoy sank but one ship, the tanker Athelbeach—by Kretschmer—in ballast. Prien and Kretschmer torpedoed and wrecked the whale-factory ship Terje Viken, also in ballast, but the hulk was finally sunk on March 14 by gunfire from two British destroyers and a corvette. Matz damaged Delilian and Mijdrecht but they reached port, as did Dunaff Head, torpedoed by Eckermann in U-A.

* In the postwar years, a popular naval historian.

* The 6,600-ton and 8,100-ton Norwegians Fern and Beduin and the 5,700-ton British Venetia. Assigning full credit for Terje Viken and Athelbeach (probably damaged by U-47 and U-70), Kretschmer sank a total of five tankers for 47,663 tons in ten days!

* The Berlin communiqué credited Kretschmer with sinking 313,611 tons, plus three destroyers, and Schepke with 233,871 tons. Dönitz had misread Kretschmer’s final message to mean that he had sunk two destroyers plus 53,000 tons on the patrol. Kretschmer’s final, confirmed score (on U-23 and U-99) was forty-three and a half ships for 247,012 tons (half credit for the whale-factory ship cum tanker Terje Viken), including three auxiliary cruisers, the destroyer Daring, and one prize. On March 21, Kretschmer was promoted to Korvettenkapitän (Commander). Schepke’s final confirmed score (on U-3, U-19, and U-100) was thirty-seven ships for 155,882 tons. Kretschmer’s score was never equaled; he remained the “Tonnage King” of the war. Schepke was to be outgunned by many skippers, winding up in 13th place. A Kapitanleutnant, he was not posthumously promoted.

 Prien’s total confirmed score, all on U-47, was thirty-two and a third ships for 202,514 tons, including the battleship Royal Oak, and half credit for Terje Viken. He stood third among all skippers in tonnage sunk. Hitler’s decision to withhold news of his loss led to numerous wild—and persistent—rumors, such as that Prien and his crew had mutinied and as punishment had been sent to a labor camp on the Russian front, where all were killed. On March 19, Prien was posthumously promoted to Korvettenkapitän.

* Because of winter ice, Sydney, Nova Scotia, was closed and Sydney, or Slow, Convoys sailed from Halifax.

* Schulz’s confirmed score—all in U-124—was thirteen ships for 57,683 tons. Oesten’s confirmed score, including six ships for 20,754 tons in the duck U-61, was twelve ships for 58,723 tons, plus damage to Malaya.

* The 4,900-ton Thirlby escaped the U-boats but was hit and severely damaged by a German aircraft while entering North Channel.

* Some of the larger Type IXs sailing to African waters carried physicians, who were regarded as noncombatants. Schulz’s decision to render assistance to these British survivors, he said later, was “approved” by Dönitz, and Schulz submitted an official account of it to the tribunal at Nuremberg to assist in Dönitz’s defense.

* This dubious distinction is often accorded the destroyer Greer later in the fall.

* The Admiralty credited Gladiolus with sinking Hoppe’s U-65 in this attack, but after further research in the postwar years, the credit was withdrawn and reassigned to the destroyer Douglas.

 In addition, the duck U-147 in British waters and the Italian submarine Tazzoli near Gibraltar each sank a freighter. As related, the IXB U-108, on a special mission in the Denmark Strait, sank a big auxiliary cruiser.

* The Italians commenced withdrawing submarines from the North Atlantic in May. The high scorer was Primo Longobardo in Torelli, who sank four confirmed ships for 17,489 tons. Second was Adalberto Giovannini in Bianchi, with three confirmed ships for 14,705 tons. The four boats lost in the North Atlantic were Tarantini, Marcello, Faa Di Bruno, and Nani.

 Eight for 77,000 tons in the last quarter of 1940 and first quarter of 1941.

* U-boats radioed contact and shadow reports to Kerneval using high-frequency bands. If Kerneval so ordered, the shadowers “homed” other boats to the local scene in medium frequencies. To prevent a pack attack, convoy escorts had to react to the high-frequency contact and shadow reports because the local “homing” signals came too late in the game. Inclusion of Huff Duff on escort ships presented a problem, however, because ships with surface-search radar could not accommodate both, and no ship wanted to leave radar behind. As a result, most Huff Duff was to be installed on convoy rescue ships and fighter catapult ships, and later on jeep carriers.

* Thirteen destroyers (six Canadian, seven British), four British sloops, and twenty-one corvettes (seventeen Canadian, four British).

 Squadron 10 at Gander with fifteen Digbys, the Canadian version of the USAAF B-18 twin-engine bomber; Squadron 116 at Dartmouth, Nova Scotia, with nine ex-British Catalinas, which the Canadians called Cansos. At this time there were eighteen U.S. Navy Catalinas at Argentia and six USAF B-18s at Gander available, for reconaissance but, of course, not overt combat. The Catalinas had an effective range of 600 miles, the B-18s 350 miles.

 Eight boats in January, eight in February, thirteen in March, and fourteen in April. However, seven new boats were held in the Baltic for R&D or for repairs or for duty with the Training Command. So great were the demands of the Training Command that eight submarines captured from the Allies were commissioned for training purposes: H.M.S. Seal, the Norwegian B-5 and B-6, the Dutch O-8, O-12, O-25, O-26, and O-27.

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