THE U-BOAT BEATEN

ALLIED SUCCESSES AT SEA

The winning of the Battle of the Atlantic was seen in 1941 and 1942, by Allies and Axis alike, as vital to their winning of the war. Churchill and Roosevelt knew that, if there was one major hinge upon which defeat might swing, it was the ability of Germany to prevent both the convoys from USA reaching Britain, and the convoys from Britain and the USA reaching the USSR. Hitler, Grand-Admiral Raeder and Admiral Doenitz believed that, given the much-vaunted Luftwaffe's demonstrated inability to subjugate Britain, their principal hope of final victory over their one enemy left in the West was to win the submarine war before the USA came officially into the conflict.

By 1942, America, whose ships had already been on active convoy protection duty for months while the USA was still neutral, had been brought into the war by Japan - an event that was as much a surprise for Hitler as it was for the United States. The Royal Navy's anti-submarine radar and Asdic techniques were improving dramatically, and despite the successes of the German U-Boat building programme, the balance was shifting perceptibly in the favour of the Allies. Nonetheless, the U-Boat remained throughout 1942 and into 1943 one of the major threats to the Allies' hopes of winning the war. An important reason for this was the continued ability of Admiral Doenitz's code breakers to read the signals of British Western Approaches Command to the convoys. For some unknown reason, British Naval Intelligence never realised that this was happening, or, if they did, never did anything to improve their coding practices. As a result, the U-Boat controllers were able not only to establish the positions of the convoys from the signals sent by the ships, but also to decode the information on supposed U-Boat positions sent to the convoys, and the instructions for avoiding the "Wolf Packs" that were given by Western Approaches Command.

By 1943, although the Kriegsmarine was becoming short of skilled U-Boat crews, and was having to keep U-boats in port at Lorient or La Pallice (and later at Brest, St Nazaire and Bordeaux) for longer between operational trips than hitherto, those boats that were at sea were hunting in larger packs with deadly efficiency. Although U-Boat losses were mounting, German production figures reached an average of between 23 and 24 submarines a month in 1943, despite heavy Allied bombing of the shipyards in which they were built. There seemed to Doenitz every prospect of sustaining the battle almost indefinitely - in fact, at the beginning of 1943, Germany had the formidable total of 212 operational submarines, more than double the number of a year previously.

Until 1943, the U-Boat arm of the Kriegsmarine had been largely spared the phenomenon of Hitler as Commander in Chief and tactician. But at the beginning of January 1943, a battle took place in the Barents Sea between the Royal Navy escort of Convoy JW 51B, commanded by Captain Robert St Vincent Sherbrooke (who was awarded the Victoria Cross for his outstanding bravery and devotion to duty) and a German force of surface raiders and submarines. This engagement, which involved Hipper, Lutzow and U-354 provoked a crisis between Hitler and the German Navy because Vice-Admiral Kummitz, in command of the German flotilla, broke off the engagement, which he might conceivably have won, before it was concluded. He did this because he was aware of Hitler's contradictory orders that Germany's prestige surface ships should not take unnecessary risks, and because, just as he knew that he might win the battle, he was also acutely aware that he might lose it.

Although it was because of his orders that the incident occurred, Hitler was furious, and vented his ire on Grand-Admiral Raeder, who promptly resigned. Doenitz, until now the Admiral that could do no wrong, was promoted Grand-Admiral in Raeder's place - but never again commanded without the baleful eye of Adolf Hitler on his every move. Thus the U-boats entered 1943 with a new commander, Rear-Admiral Godt, and without the moral support of the surface raiders, which were effectively retired from active service for the time being as a result of Hitler's outburst.

The year also saw the eclipse of the Luftwaffe as an effective strike and defensive force at sea, which enabled the Allied air forces to become ever more effective at anti-submarine operations. During 1943, the RAF sank 41 U-boats in the Bay of Biscay without significant response from the Luftwaffe , and the production of escort carriers, mainly in United States shipyards, was stepped up to provide much wider airborne protection for convoys at sea. By the end of 1943, aircraft from escort carriers had destroyed no fewer than 26 U-boats. Typically, these mass-produced American ships of around 10,000 to 12,000 tons were built from scratch in less than a year. Like the other rapidly produced products of the American shipyards, notably the "Liberty" ships, they made a very significant contribution to the Allied war effort.

Losses of merchant ships from the convoys were also reduced by the application of research into the history of convoy losses. It was found that, contrary to popular belief, large convoys were safer than small ones. Although easier to find, the large convoys, it was observed, lost only the same number of ships as a smaller convoy, given constant numbers of attacking submarines. In other words, six submarines could be expected statistically to pick off roughly the same number of "kills" from any convoy, almost regardless of its size. Since a large convoy required a smaller number of escort vessels as a proportion of the total number of ships in the convoy to achieve the same degree of safety, it followed that more large convoys could be escorted by the same number of warships with fewer losses overall.

All these developments tended to decrease Allied shipping losses and increase the sinkings of German submarines. But of the four decisive advances that turned the Battle of the Atlantic and gave the Allies the upper hand, two were electronic and two were major advances in maritime weapons systems.

The first was the advent of centimetric radar. Installed on board the convoy escort vessels, this form of short-wave radar could not be spotted by the U-boats' detection equipment, which was designed for the much lower frequencies until then in use. The U-Boats had come to rely extensively on their ability to track convoys and find them at night by the detection of their radar emissions. Suddenly this facility was denied them.

The second electronic development was "Huff Duff", otherwise and more correctly known as H/F D/F or High Frequency Direction Finder. This goniometric radio equipment was able to provide a fix on any U-Boat transmitting radio signals. With this equipment installed, the convoy could be steered away from the U-Boat packs, and the "Hunter-Killer" Allied submarines could be directed on to their kill.

The first of the weapons systems that helped to end the Battle of the Atlantic was the "Hedgehog", a projector in the bows of an escort vessel capable of firing a pattern of 24 contact-fused bombs for 250 yards ahead. By making it unnecessary for the escort to pass directly over its target before succeeding with depth charges, and by providing a larger spread of fire and less chance for the submarine to detect the presence and position of the escort, the "Hedgehog" greatly increased the success rate of escorts against U-boats.

The fourth contributor was the airborne rocket. Increasingly being brought into use as a tank-busting weapon by the Allies, the rocket was shown to be every bit as effective against submarines on the surface, and speedily contributed to U-Boat sinkings from the end of May 1943 onwards.

With all these new-found advantages, the Allies turned the tide of the Atlantic war dramatically. The decisive year began, in January 1943, with a relatively quiet month in the North Atlantic because of appalling weather - only 50 Allied merchant vessels were sunk - but Doenitz achieved a major success off North Africa by sinking seven of a convoy of nine tankers carrying vital fuel to the Allied armies closing in on General von Arnim's army in Tunisia. In the next month the weather improved and so also did the German score. A total of 73 ships went to the bottom. But so did 19 U-boats, and the much greater success of the escorts in defending the convoys, as well as in sinking the submarines, was causing great concern at Kriegsmarine headquarters.

March seemed almost to reverse the situation. The carnage of Allied ships was awe-inspiring. In the first twenty days of the month no less than 97 Allied ships were sunk, almost two-thirds of them in properly escorted convoys. By the end of the month the total had passed 100 and settled at 102. Only 15 German submarines were destroyed during the month. For a moment it seemed to the Allied seamen that all was lost. But their commanders knew of the new weapons; were certain the battle was about to turn. April saw only half the Allied losses for a further 15 U-boats sunk. May brought 47 U-Boat losses for fewer Allied ships sunk than in April. Doenitz recognised defeat when he saw it.

On May 24th, Doenitz withdrew the U-Boat fleet from the Atlantic for modification and improvement. In July, the German submarine fleet reappeared in the Atlantic fitted with quadruple cannon on the conning towers. But this expedient proved useless against the Allied aircraft with their rockets, bombs and depth-charges. During the month of July, 37 more U-boats went to the bottom. In August a further 23 were destroyed.

By December 31st 1943, despite the intensive construction rate of U-boats throughout the year, the German submarine fleet was down to 168 operational vessels, as compared with 212 a year earlier. U-boats were no longer able to attack, or even operate, on the surface, and were forced to observe radio silence or be detected. Gone were the days of German superiority in radio communications. Gone was Doenitz' ability to direct his wolf-packs on their target without also calling in the Allies to their kill. Germany had lost the Battle of the Atlantic.