from “Hitler’s U-Boat War” , Clay Blair Jr
“The War for the Seas” - Ewan Madsley
“Hitler’s U-Boat War” David Mason
“Atlantic Campaign” Van der Vat
“Donitz , The Last Fuhrer” - Peter Padfield
“Donitz andthe Wolfpacks” - Bernard Ireland
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.
Still , Whitehall , War Office in 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,(British and Canadians built 77.000 ton of shipyards between last quarter of 1940 and first quarter of 1941) and to various Lend-Lease measures to supply American and other foreign tankers to the British (Norwegian mechant marine in exile had the largest tanker fleet of the world and on the whole passed to Allied service after invasion of Norway , which was a big blow to tonmnage war goals of German Navy) , 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 British dmiralty, RAF Coastal Command had built air bases in Iceland and the Faroes, 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 intelligence had penetrated German Naval Enigma wireless coding. Should the British Admiralty’s other planned captures succeed (as we shall see most did) , 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.
On top of that week by week the United States had become more deeply involved in the Battle of the Atlantic. After passing Lend Lease Bill and signing it , President Rosevelt was trying to find new ways to aid Britain and its war effort. In addition to the measures already described, in response of Hitler’s decleration of Atlantic waters west of 36 parallel would be operational zone for German Navy , on April 18 US Atlantic Fleet commander Admiral 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,(thirtheen destroyers , four sloops and tenty one corvettes) 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 (wartime raw material transport for war production , oil and food import actually slightly increased ), but bad enough because necessary sea transport tonnage for these imports was not decreasing significantly as Donitz hoped to starve British war effort but not increasing fast enough either for Britain and her Allies to expand its war capabilities faster…
While Operation Barbarossa (invasion of Soviet Union ) was being prepared in first half of 1941 and Germans entered Balkan/Mediterranean Theaters , the Kriegsmarine was to continue pressure on the British, tying down naval and air forces and blocking any and all British attempts to assist the Soviets, such as another invasion of Norway. But on per to Hitler’s orders , all U-boats and merchant-ship raiders were to take special pains to avoid any “incident” with the United States that might provoke Washington to open intervention during Barbarossa. Commencing in late May 1941, newly commissioned Type VII U-boats departed the Baltic for battlefronts in ever increasing numbers: twelve in June, nine in July, twelve in August. This was a far cry from the “twenty-five to thirty” new U-boats per month envisioned in the construction programs of 1939 but double or triple the usual monthly rate of new arrivals in the Atlantic, and therefore the first significant increase in force levels since the onset of war. Owing to the slight battle losses incurred from December 1940 to May 1, 1941 (seven), and to a continuation of that modest trend through the summer months, Dönitz had the means not only to intensify the U-boat war in the “decisive” North Atlantic arena, but also to send another wave of Type IXs to the promising waters of West Africa (during March a four U-Boat group pack created havoc on West African shores across Sierra Leone and Freetown , sinking 34 mostly single sailing merchant ships totalling appox 129.000 tons of shipping in five weeks and on top of that torpedoing a damaging Queen Elisabeth Class battleship HMS Malaya which had to be sent to US East Coat for damage repair. There were weak spots like that in British shipping lanes across the globe) .
However , the first important event of the Battle of Atlantic during 1941 , occured in 3 May 1941 , Tribal class Royal Navy destroyer HMS Somali intercepted and captured German weather ship Munchen in North Sea. German crew had thrown their Enigma machine overboard before boarded by British boarding party but after overtaking the Germans , British naval personnel discovered most of the Enigma keypads , cribs and short signal documents were intact. These were all gathered up along with intanct Munchen and brought to Scapa Flow , from there Enigma materiel captured was sent to Goverment Cypher School in Bletchley Park where along wqith all material and Enigma machine captured from U-110 (as mentioned below) together , they would prove an immense treasure hove for British crypto analysers.
Nineteen U-boats sailed to the North Atlantic in May. The first, U-94, a VIIC commanded by Herbert Kuppisch, reported a convoy south of Iceland on May 7. This was Outbound OB 318, which had sailed from the British Isles with thirty-eight ships. It was heavily guarded by Escort Group 7, commanded by I. H. Bockett-Pugh, composed of ten warships: three destroyers (including the ex-American four-stacks Campbeltown and Newmarket), five corvettes, a sloop, and an ASW trawler. Coastal Command aircraft from Iceland and Scotland provided air cover. Per plan, three ships had left the convoy earlier that day to put into Iceland. Five other ships, including the 10,000-ton liner Ranpura, an armed merchant cruiser, had joined, making a total of forty ships. At the time Kuppisch detected the convoy, a complicated change-up in the escort for Outbound OB 318 was in progress. Escort Group 3, commanded by Addison Joe Baker-Cresswell, had sailed from Iceland to relieve Bockett-Pugh’s Escort Group 7 for the middle leg of the trip. Composed of nine warships (three destroyers, three corvettes, three ASW trawlers), Escort Group 3 had in company the auxiliary cruiser Ranpura and four freighters that were also en route from Iceland to join OB 318. To assure a safe changeover of the escort groups, the sloop Rochester and five corvettes of Bockett-Pugh’s Escort Group 7 were to remain with the convoy for an extra twenty-four hours before going to other duties. Hence there were fifteen warships in the vicinity of OB 318. It was a bright moonlit night and, after broadcasting the convoy contact, Kuppisch elected to attack submerged. He let the lead escorts pass and gained a position in the middle of the convoy, “between two 10,000-ton liners,” probably the British ships Ranpura and Ixion. He then fired four torpedoes into the columns of ships. He claimed sinking four vessels for 20,000 tons, but actually only two sank: the 10,300-ton Ixion and a 5,700-ton Norwegian freighter. The flagship of Escort Group 3, the destroyer HMS Bulldog, joined by the destroyer HMS Amazon and the Escort Group 7 sloop HMS Rochester, pounced on U-94 and, during four hours, dropped eighty-nine depth charges, “a severe and accurate counterattack,” Kuppisch logged, “which caused considerable damage.” The counterattack prevented a second attack by U-94, but Kuppisch repaired the damage and continued his patrol.
Acting on Kuppisch’s contact report, Dönitz alerted six other boats that were patrolling west of Iceland. Two boats found the convoy in bright moonlight during the night of May 8: Fritz-Julius Lemp in U-110, from Lorient on its second patrol, and the new VIIC U-201, commanded by Adalbert Adalbert (“Adi”) Schnee, who began the war as first watch officer of Kretschmer’s U-23 and later commanded the ducks U-6 and U-60. Lemp had been on patrol three weeks and had sunk one 2,500-ton freighter. Sailing from Bergen, Schnee had been on patrol one week. He had polished off the abandoned hulk of the tanker Capulet (wrecked by Topp in U-552) and possibly a 2,000-ton steamer. Lemp and Schnee met on the morning of May 9, ahead of the convoy, which at that time had no air cover. Since a bright moon was expected again that night, they agreed that a surface attack would be dangerous. And since they assumed that by then the escorts had left the convoy, the two skippers (communicating by signal flags) elected to attack submerged in daylight as soon as possible, possible, to avoid the possibility of losing the convoy. The senior man (and Ritterkreuz holder) Lemp was to go first; Schnee was to attack half an hour later, after the convoy had been thrown into confusion by Lemp’s attack.
Lemp submerged and let the convoy come on. Surprised to see the escorts, he nonetheless decided to continue with the attack. At about noon, he hit the convoy’s right flank, setting up on four different ships, three of which he believed he sank. In actuality, two British freighters, the 5,000-ton Esmond and the 2,600-ton Bengore Head, went down. The fourth torpedo misfired, but after it had been readjusted, Lemp prepared to shoot at a tanker. The convoy executed an emergency turn to port and when Schnee attacked about thirty minutes later, he shot into what was then the rear , of the formation. He hit two 5,900-ton freighters, the Gregalia, which sank, and the Empire Cloud, which was severely damaged and abandoned, but later salvaged and towed to Scotland.
At the time of these attacks, the convoy was guarded by the nine warships of Baker-Cresswell’s Iceland-based Escort Group 3. The flagship, the destroyer HMS Bulldog, along with the ex-American four-stack destroyer HMS Broadway and one of the three corvettes, HMS Aubrietia, hunted U-110, which was still at periscope depth, preparing to shoot at the tanker. All three escorts obtained firm sonar contacts. HMS Broadway attacked, dropping a single depth charge. Seeing Lemp’s periscope, HMS Aubrietia, commanded by V. F. Smith, attacked it twice, dropping sixteen well-placed depth charges set for 100 and 200 feet.
The depth charges from Aubrietia fell very close to U-110. The blasts smashed the diving gauges and other instruments, knocked out the electric motors, diving planes, rudder, and compass, ruptured an aft fuel or ballast tank, sheared off the high-pressure air valves in the control room, and generated chlorine gas in the forward battery. Flooding aft, the boat went out of control and slid stern first to 300 feet. Seeing that U-110 was beyond all hope, Lemp ordered the engineer to “prepare for emergency blow,” which would bring them up. But before he could give the order, Lemp and the crew felt an “unexpected rocking motion,” indicating that the boat had surfaced of its own accord, perhaps owing to a rupture in a high-pressure air line, which blew the ballast tanks.