Figure 1.--

The Battle of the Atlantic was finally decided with climatic convoy battles (May 1943). Allied naval escorts and aircraft with improving technology managed to destroy substantial numbers of U-boats during Wolf Pack attacks on convoys. The turning pount was ONS-5. The convoy manages to fight off the U-boat wolf packs with only a small escort force. Other losses occured during May and with expaned aerial covrage, the U-boat losses were unsustainable. Dönitz did not withdraw completely from the Atlantic. He calculted that a minor continued commitment would force the Allies to maintain major forces in the Atlantic. The Allies greatly expanded their air coverage, both long range aircraft and escort carriers. Both the Americns and British formed formidable hunter-killer groups. As Allied ASW capabilities continued to improve, many of the U-boats that did go out never returned. The hunter became the hunted. And Allied air patrols were no longer limited to visual spotting, but radar capable of picking up even a persisope. The U-boat service became the most dangerous service of the War. The last important opportunity that Dönitz's U-boats had to play in the War was the Allied cross-Channel invasion D-Day. The plan was once the invasion began that the U-boats would mass in the Channel and sink Allied shipping. The Landwirte Group of 36 U-boats was given the task of atttacking invasin shipping. Unlike the land forces, they did not need to know which landing beach and when. The U-boat effort, hwever, was a total failure. The Allied plugged both ends of the Chnnel with mines, destroyers abd escorts wth ASW capability, and aerial patrols--Operation Cork. As a result, very few U-boats broke into the Channel after D-Day. [Schofield] Few of the U-boats succeeded. There wwre a few successful attacks: HMS Blackwood, Columbine, SS Maid of Orleans, and a few smll ships. Several more ships were damaged. Given the Dimensions of the Allied naval force, the whole effort was ineffectual. The Germans worked on technical innovations of their own. They developed a stealth U-boat with ruberized coverings of the hull. The U-480 was fitted with this covring. It was effective, but developed too late to have any real impact. U-480 was sunk by a minefieldin the Channel laid as a result of Enigma decrypts (February 1945). By 1945, Allied ASW capabilities were so advanced that it was nearly a death sentence for a German crew to take a stabndard U-boat out on patrol in a standard U-boat. The Germans developed the Type-XXI Elektroboot. It had nmany advanhced features, but had a range of problems. And the Allied strategic bombing campaign delayed and complicated construction. Thus the few boats built never went out on a combat patrol. The primary use of the U-boats after D-day was to ship secret technology and enriched uranium to the Japanese. Rumors after the War circulated that U-boats were being used to help top NAZIs escape. There is no evidence of this. Until commiting suiside, Hitler was having people shot for admitting defeat. And there is no evidence that Dönitz facilitated the escape of any NAZI war criminal. The last U-boat sunk by the Allies was the U-3523, a Tyoe XXI. It was sunk by a British crewed B-24 Librator in Danish waters -- the Skagerrak Straits (May 6, 1945).

Allied Victory in the Atlantic

The Battle of the Atlantic was finally decided with climatic convoy battles (May 1943). Allied naval escorts and aircraft with improving technology managed to destroy substantial numbers of U-boats during Wolf Pack attacks on convoys. The turning pount was ONS-5. The convoy manages to fight off the U-boat wolf packs with only a small escort force. Other losses occured during May and with expaned aerial covrage, the U-boat losses were unsustainable.

German Contnued Minimal Commitment

Adm. Dönitz did not withdraw completely from the Atalantic. He calculted that a minor continued commitment would force the Allies to maintain major forces in the Atlantic.

Allied Perfecting ASW Capability

The Allies greatly expanded their air coverage, both long range aircraft and escort carriers. Both the Americans and British formed formidable hunter-killer groups. As Allied ASW capabilities continued to improve, many of the U-boas that did go out never returned. The hunter became the hunted. And Allied air patrols were no longer limited to visual spotting, but radar capable of picking up even a persisope. The U-boat service became the most dangerous service of the War.

D-Day (June 1944)

The U-boats were largely withdrawn from the North Aatntic (mid-1943). They were thus unable to stop American troop tansports and the enormpus Allied buildup for the cross Channel invasion. Fast ships like pssenger linrs wre used for the troop trnsports. They were so fast that convoys were not needed. By Spring 1944 it was clear the Allies were going to land in France. The timing and location, however, were unknown. Defeaing the landings were the NAZIs bet chnce of avoiding defeat. If the ladings were defeated, the full force of the German war machine could be focused on the advabcing Red Army in the East. The last important opportunity that Dönitz's U-boat force had to play in the War was the Allied cross-Channel invasion D-Day. The plan was once the invasion began that the U-boats would mass in the Channel and sink Allied shipping. Dönitz had pulled the U-boats out if the North Atlantic in mid-1943. He still had a considerable force. Hitler demanded that they be committed to oppose the D-Day landings. The Allies had assembled a hughe armada of 800 ships and 4,000 landing craft. The U-boats made a major effort to stop the landings. The Allies assumed that the U-boats would be committed against the landings and supply vessels. The Allies were well aware that thhe Germans would use U-boats to oppose the invasion. They position both aiur craft and ASW ships to protect the sea lanes across the Channel. A force of 375 aircraft patrolled the Channel. Ships were deployed to block access to the Channel. The Allied plugged both ends of the Channel with mines, destroyers abd escorts wth ASW capability, and aerial patrols--Operation Cork. Dönitz like the rest of thecWehrmacht assumed that the Allies would land in the north at the Pas de Calais. This when the Allies landed further south in Normandy, he was unprepared to oppose the Allied landing force. He move quikly to cancel leaves and prepare available U-boats in the French Atlantic ports. Dönitz was able to send out 36 U boats from the French Bay of Biscay ports. The Landwirte Group of 36 U-boats was given the task of atttacking invading shipping. The U-boat effort was a total failure. As a result, very few U-boats broke into the Channel after D-Day. [Schofield] Few of the U-boats succeeded. The 28 U-boats from French ports without snorkles were easily spotted, 10 were destoyed or danaged. The 8 U-boats with snorkels fared better, but did not penetrat the line of patroling ASW waships. None of the U-boats get through. More snorlel boats were sent from the north. A few slipped through, but did little damage. There wwre a few successful attacks: HMS Blackwood, Columbine, SS Maid of Orleans, and a few smll ships. Several more ships were damaged. Given the Dimensions of the Allied naval force, the whole effort was ineffectual. They were ordered to stop the Allie at all cost. After the Allied breakout from Normandy (July 1944), the French Atlantic ports were isolted and taken. The U-boats in the Atlantic were ordered to Norwegian ports. This meant that it would take much longer to get out into the Atlantic.

German Technological Advances

The Germans worked fevirosly to improve their U-boats. German inelligence failed to report on many of the Allied techhnological advances. A suken U-boat could not report on the action. The German made technological improvements of their own. The Germans developed acoustical torpedoes which permiited attacks on hard to hit escorts. Normal torpedoes were designed to hit slow moving cargo vessels that sat depnin the wter. The fast moving escorts had more shallow drfts. The Allied sollution to the acoustical torpedo was to tow an inepensive noise-making buoy. The major weakeness of the U-boat was the need to run on the suface at least a night to recharge the batteries. The Germans introduced snorkles which allowed the U-boats to run underwater without surfacing. The snorkles had two pipes, one for exhaust and the other to draw in fresh air. They allowed the subs to move much longer while submerged. Improving Allied radar, however, was eventually able to detect even the snorkle. And there were problems with its use, especially in bad weather. The Germans strengthen the hulls permitting deeper dives to get away from the attacking ecorts. The Germans worked on technical innovations of their own. They developed a stealth U-boat with ruberized coverings of the hull. The U-480 was fitted with this covring. It was effective, but developed too late to have any real impact. U-480 was sunk by a minefieldin the Channel laid as a result of Enigma decrypts (February 1945). By 1945, Allied ASW capabilities were so advanced that it was nearly a death sentence for a German crew to take a stabndard U-boat out on patrol in a standard U-boat. The Germans developed the Type-XXI Elektroboot. It had nmany advanhced features, but had a range of problems. And the Allied strategic bombing campaign delayed and complicated construction. Thus the few boats built never went out on a combat patrol. The last U-boat sunk by the Allies was the U-3523, a Tyoe XXI. It was sunk by a British crewed B-24 Librator in Danish waters -- the Skagerrak Straits (May 6, 1945).

Technology Trnsfers to Japan

After the Allies won the Battle of the Atlantic (July 1943), the Atlantic became a very dangerous place for U-boats. The Germans no longer threatened the sea lanes to Britain. A new concern surfaced for naval commaznders, stopping the Germans frim transferring advanced weapons technology to the Japanese. Germans scientists had develkoped highly advanced weapon sustems, including jets, rockets, radar, and much more. Of greatest concern for the Allies was nuclear technology amd material. Unlike the very close Anglo-American technological, there was virtually no technological cooperation between the Axis partners. The one exceptuion here was German assistance to the Japanese before the War in developing high-performance aircraft. The reason for this lack of cooperation is not clear. It is like that the NAZIs were so confidebt of victory in the ealy years of the War that they saw no advantage to strenthening a possuble future adversaery. This changed in 1943 after the Soviet destruction of the 6th Army at Stalingrad. As the War turned against the NAZIs, they became increasingly interested in assisting the Japanese. The problem was that after Stalingrad it was no longer possible for long-range German aircraft to reach Japan and virtually impossible for surface ships to break through the Allied blockade. We know that there wre deliveries by U-boat, although even this was difficult by late 1944. U-boats delivered rocket and jet technology to Japan which helped them to begin construction of a series of advanced aircraft. The U-234 after the German surrender on May 8 decided to surrendered to the U.S. Navy. It contained lead cases holding Uranium oxide. It is unknown what this was for, but the most likely explantion was a dirty atmic bomb.

NAZI War Ciminals

Rumors after the War circulated that U-boats were being used to help top NAZIs escape. There is no evidence of this. Until commiting suiside, Hitler was having people shot for admitting defeat. And there is no evidence that Dönitz facilitated the escape of any NAZI war criminal.

Created: 5:40 AM 6/29/2018
Last updated: 5:40 AM 6/29/2018