Hitler, Donitz, and the Baltic Sea (35 page)

To continue the fight until the Type XXI and XXIII submarines became available, then, Dönitz needed stopgap measures. These included improved torpedoes, heavier antiaircraft armament, and the snorkel. More so than earlier, submarines now had to destroy convoy escorts before attacking the merchantmen. The navy was hard at work on an antidestroyer torpedo, which Dönitz hoped to have ready by the end of the summer.
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On 24 May 1943 Dönitz ordered that all submarines located by aircraft should remain on the surface and engage the enemy with antiaircraft guns unless they could dive to eighty to a hundred meters before the plane released its bombs. This tactic only led to greater losses. By the end of June Dönitz ordered all U-boats to travel underwater through the Bay of Biscay in conditions of poor visibility, although this increased the transit time through this dangerous area.
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In any event, submarines still had to surface for four to five hours daily to recharge their batteries.

From the latter part of 1942 there were growing indications that the Allies were using airborne radar to locate submarines, yet the Skl virtually ignored this threat until too late. In mid-May 1943 Walter reported he had discovered an effective countermeasure to Allied location systems—U-boats fitted with tubes through which to draw in air and expel exhaust could travel at periscope depth on their diesel engines rather than their electric motors. This would eliminate the need to surface to recharge batteries. Walter pointed out that it was unlikely the Allies could locate so small a device from the air. This apparatus, the snorkel, was not a new invention. When the Nazis overran Holland in May 1940, they had found Dutch submarines fitted with an air mast. The Submarine Acceptance Commission had tested the device, and the Naval Construction Office had suggested trying the snorkel on a submarine in combat, but Dönitz rejected the proposal. When the snorkel finally went into production in 1943, it did so without further tests and with only minor modifications recommended by Walter.
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A valuable opportunity to evade radar had been squandered in the meantime.

Although the Skl considered location devices the bane of its U-boats, there were actually a number of reasons for the Allied victory in the Atlantic in the spring of 1943. The Allies had recognized the serious threat posed by U-boats and devoted considerable human and material resources to develop effective countermeasures. Unknown to Dönitz, in May 1941 the
British had captured a German submarine with its Enigma code machine, complete with instructions. After studying the Enigma machine the Allies were able to decipher messages to and from the U-boats. Knowing the location of submarines allowed the British to reroute convoys and dispatch antisubmarine forces to attack them.
²²
The Germans stubbornly believed their codes were unbreakable and made few changes in signals communication. But even the ability to decipher the German Navy’s messages, though it was a key development, alone did not account for the Anglo-American success. Another vital factor was the Allies’ ability to provide air cover over the entire North Atlantic with escort carriers and very-long-range aircraft operating from land. The formation of support groups to hunt U-boats and assist convoys under attack also increased German submarine losses. In addition, the introduction of ten-centimeter-wavelength radar, high-frequency direction finding (HF/DF, or “Huff-Duff”), and new antisubmarine weapons all played key roles. The German obsession with devising countermeasures to radar caused them to ignore the threat from decryption and direction-finding equipment. Although Dönitz blamed Allied aircraft for the turn of the tide in the U-boat war, at least when he was with Hitler, in fact the navy was not blameless, having allowed the enemy to gain the technological lead and failed to make submarine construction a priority.
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In the meantime the Battle of the Atlantic continued to go badly for Germany. At the beginning of August 1943 Dönitz reported that the U-boat war would remain costly until the new submarines became available. Hitler acknowledged this but insisted that the war at sea continue to keep Allied vessels engaged in defensive operations. In July the Germans lost twenty-seven U-boats, and the following month thirty-two submarines failed to return, over half the monthly average operating in the Atlantic.
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At the beginning of 1944 the Skl reviewed the status of the U-boat war. In an attempt to make a steadily deteriorating situation look better, the Skl emphasized that despite the loss of 227 submarines, 1943 had been the second most successful year of the war. Dönitz assured Hitler he would continue the fight until the new models of submarines were ready, pointing out as a problem that the Baltic was the sole training area for the new U-boat force. On 7 January Dönitz abandoned his wolf-pack tactics, ordering submarines instead to operate in groups of three or even individually. Massed attacks against convoys held little promise until the new submarines became operational.
²⁵
This was yet another admission of defeat in the Atlantic.

In January 1944 the Central Board for Ship Construction anticipated the completion of the first three Type XXIs in April and a total of 152 by
the end of October. The first two Type XXIIIs were to be delivered in February, and the full complement of 140 by the end of October. The revival of the U-boat war was only a few months away—or so Dönitz led Hitler to believe. He soon had to explain, however, that the new U-boat war would not begin as soon as planned. At the end of February Dönitz reassured Hitler that the new submarines’ high speed would permit them to overtake convoys and that furthermore, since they would operate underwater, the enemy could not detect them as easily, because sonar range was much less than radar. Dönitz added, however, that a recent air raid had seriously damaged the new submarines’ electric motor factory in Berlin, resulting in a two-month delay.
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In mid-April Dönitz reported further delays to the Types XXI and XXIII due to bomb damage to an Augsburg factory producing motors. A few weeks later he explained that shipyards in Hamburg, Bremen, and Danzig required additional air defenses, which Hitler ordered Göring to provide. Dönitz also complained that the shortage of workers meant that the navy now expected delivery of only 140, instead of 218, U-boats in 1944; Hitler protested that he had not ordered any reduction in workers for submarine construction. Nevertheless, Dönitz promised, the first Type XXIII would still be ready for action in October 1944.
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On 6 June the Allies landed in Normandy, and a few days later Hitler requested a status report on the new submarines. At this time snorkels had been installed on only a handful of U-boats, and these had been sent into the English Channel. Initial reports from snorkel-equipped submarines were encouraging. U-boats fitted with this device had been located by the enemy, but ensuing attacks had been inaccurate. The snorkel seemed the best intermediate measure available until the arrival of the Type XXIs and XXIIIs, now scheduled for the winter of 1944–45.
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In fact, in the following months the performance of snorkel-equipped U-boats exceeded Dönitz’s initial optimism. The Skl boasted that a submarine had returned from the English Channel after remaining submerged for forty days. Although the U-boats fitted with snorkels did not achieve any spectacular success in the Channel, they were able also to operate off Britain’s east coast, in the Irish Sea, and off Gibraltar, areas into which German submarines had not ventured for three to four years.

The Skl noted with satisfaction that after U-boats had begun to operate solely underwater, losses dropped to the 1941–42 levels. This proved invaluable for boosting U-boat crews’ morale: snorkel travel granted security. But it did so at the cost of mobility, because the time required to journey to and from operational areas increased considerably,
due to the slow underwater speed of existing submarines. Although the Germans kept a large number of U-boats at sea, each submarine spent only a fraction of the time at sea actually on patrol. Nonetheless, Dönitz repeatedly emphasized that the snorkel’s success justified his expectations for the electro-submarines, which would perform immeasurably better.
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The snorkel had proved an effective remedy to air power. With the submarines’ disappearance from the surface, visual search became more effective for the Allies than radar search. Until the end of the war the Anglo-Americans remained unable to produce an effective countermeasure to the snorkel.
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On 19 April 1944, the day before Hitler’s birthday, the first Type XXI submarine was launched.
U-3501,
however, had been launched rather prematurely. Openings in the hull had been patched with wood, and the U-boat returned to dry dock immediately after launching. It was not delivered to the navy until 11 July; it was commissioned on 28 July. The first Type XXI commissioned was
U-2501,
delivered on 15 June and commissioned on the 28th. Although it had not been launched prematurely, it still required ten days’ work in July to correct faults. The first Type XXIII,
U-2321,
was launched on 17 April 1944—also too soon; it was commissioned only on 12 June. Prestige, not readiness, was the key criterion for these launching dates.
³¹
Other new-type submarines followed, although not as quickly as Dönitz had promised Hitler. In the meantime Dönitz’s insistence on continuing the U-boat war exacted a heavy price: Germany lost twenty-seven submarines in July and thirty-three in August 1944. By 1 November a total of thirty-one Type XXIs and sixteen Type XXIIIs had been commissioned.
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This amounted to but a fraction of the 152 Type XXIs and 140 Type XXIIIs Dönitz had originally planned to have at this time.

Despite this drastic reduction, Dönitz continually promised Hitler that the new U-boat war would soon begin. On 13 October 1944, exactly one week before Hitler ordered Army Group North to defend Courland, Dönitz met with Hitler. He stressed the importance of the Baltic for naval training, adding that he planned to send the first Type XXIIIs into action in January 1945, followed by forty Type XXI Atlantic U-boats in February. Surely Hitler believed that the simultaneous introduction of forty of these new submarines would bring spectacular results. At about the same time Dönitz assured Goebbels that the Type XXI U-boats would sail against enemy convoys in January. On 5 October 1944, however, the Skl had informed the Luftwaffe that the new U-boat war would begin in April 1945.
³³
Dönitz was attempting to convince Hitler that the revival of the U-boat war was just around the corner—when he knew that it was not. Submarine construction
continued to fall behind even revised estimates. In early September 1944 the navy planned to have 120 Type XXIs and 46 to 50 Type XXIIIs by the end of the year. The actual numbers on 1 January 1945 were sixty-two Type XXIs and twenty-eight Type XXIIIs, despite an increase, achieved by Speer, in total submarine construction in 1944.
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At the beginning of 1945 Dönitz reviewed the statistical performance of U-boats per operational day. He concluded that submarines in December 1944 had achieved the same individual rates of success as in August 1942. The substantially lower actual tonnage sunk compared to 1942 resulted from the smaller number of submarines at sea and the increased time required for submerged travel to and from operational areas. This would change, however, with the arrival of the electro-submarines, whose submerged cruising speed was nearly twice that of current U-boats. If existing U-boats could achieve such success, then, stunning victories with the new-type submarines could be anticipated; Dönitz confided to Goebbels that he expected to launch the first convoy battles with the new submarines in February. In mid-February 1945 Dönitz informed Hitler that results from January confirmed this trend. He promised Hitler a sizeable increase in the number of U-boats at sea in the coming months, sixty per month, including the new-type submarines.
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Despite Dönitz’s repeated promises that the new U-boat war lay just ahead, it never arrived. By the end of the war fifty-nine to sixty-three Type XXIIIs had been built. Only five or six had put to sea, the first on 29 January 1945 and the last on 4 May. None was sunk while engaged in operations, and Dönitz reported their performance had been excellent. In fact, the biggest problem was that their commanding officers underestimated their speed. They approached too close to their targets, moving so rapidly that they fired the torpedoes within the safety range, inside which they were not armed.
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The Germans commissioned approximately 120 Type XXI U-boats by the end of the war.
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Adalbert Schnee’s Type XXI (mentioned in the introduction) left Kiel for Norway on 17 March 1945, but a problem with its periscope postponed operations. On 17 April
U-2511
again put to sea, but it had to return four days later due to problems with its diesel engines. Schnee finally sailed on 30 April 1945, just over seven months after
U-2511’
s delivery on 29 September 1944.
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Only one other Type XXI left port in search of enemy vessels.
U-3008,
commanded by Helmut Manseck, left Wilhelmshaven on 3 May 1945 but, like Schnee’s boat, received Dönitz’s order to cease attacks. Dönitz had based his entire strategy for nearly two years on the deployment of these submarines, and they never fired a shot.

The British and Americans first learned of the new German submarine program in November 1943, and in April 1944 air reconnaissance revealed a “double shock.” Not only were the new-type submarines already under construction, but the use of prefabricated sections made assembly time alarmingly brief. One submarine had been launched after only six weeks’ slip time. Decrypts of signals from the Japanese naval attaché provided the British with detailed information on the Types XXI and XXIII in the spring of 1944. Deciphered messages from the head of the Japanese Naval Mission, Admiral Katsuo Abe, informed the Allies that air raids had delayed the new U-boat offensive until the spring of 1945. This information led to increased bombing raids as well as mining operations in the Baltic to disrupt training.
³⁹
Exact knowledge of these new submarines, however, did not lead to complacency on the part of the Allies. The submerged speed of the Type XXI U-boat was higher than that of Allied corvettes and only slightly slower than frigates. The only vessel that could have effectively dealt with the Type XXI was the destroyer, and the British were chronically short of destroyers. The British Admiralty feared that shipping losses could exceed those from the spring of 1943, and for this reason the British held back approximately three hundred destroyers and escorts originally intended for action in the Pacific.
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