The Second World War (18 page)

Apologists for the British effort could show, however, that two-thirds of the ships lost had been sunk out of convoy and that U-boat losses for the year totalled 28, suggesting that the escorts’ success was increasing. Dönitz was certainly prepared to draw that conclusion: as soon as the United States Navy became an overt combatant rather than a hostile neutral (as it had been since September 1941), he transferred the weight of his effort to the United States coast. From January 1942 onwards, up to twelve U-boats were cruising off the American east coast and in the Gulf of Mexico at any one time; between January and March they sank 1.25 millon tons of shipping, equivalent to an annual rate four times higher than that achieved in the North Atlantic during 1941.

By May, however, convoy had been introduced on America’s Eastern Sea Frontier and sinkings at once declined in those waters. Moreover, the rate of new building, both of merchantmen and escorts, began to accelerate spectacularly, as the American shipyards revived and were mobilised for new construction. Of particular importance was the appearance of a standardised tanker, the T10, and a freighter, the Liberty ship, both of which were larger (14,000 and 10,000 tons) and faster than their pre-war equivalents, besides – most important of all – being quick to build. Three months was the average construction time; by October 1942 American yards were launching three Liberty ships a day and in November the
Robert E. Peary
was built from the keel up in four days and fifteen hours – a public-relations stunt, but grim evidence to Dönitz of the challenge that prefabrication techniques posed to the efforts of his U-boat captains.

By July 1942, though neither side yet perceived it, the Battle of the Atlantic was approaching its crux. There were diversions from the central issue. In March 1942 the British destroyed the dock at Saint-Nazaire which offered an Atlantic coast home to the
Tirpitz
, Germany’s largest battleship. It was then harboured in north Norway, where it had been joined in February by the
Scharnhorst
and
Gneisenau
after their daring dash through the Channel – an incident that provoked much recrimination between the Admiralty and the RAF over who bore responsibility for the failure to intercept them. The three heavy ships levelled a menace against the Arctic convoys for months to come and caused lethal disruption to convoy PQ17 in July. In December 1943
Scharnhorst
made a brief sortie against an Arctic convoy, provoking much anxiety at the Admiralty, but suffered an identical fate to that of
Bismarck
; and the
Tirpitz
menace did not end until November 1944 when she was sunk by bombing at her moorings in Troms| Fiord. But these episodes largely summarise the contribution of the German surface fleet to the
Kriegsmarine
’s war. The need to mount the North African ‘Torch’ landings in November 1942 temporarily drained away Allied merchantmen and warships from the Atlantic lifeline. There was a serious interruption of Ultra decrypts of U-boat radio traffic in February 1942 which lasted for most of the year, at a time when the B-Dienst was enjoying increased success against the Royal Navy’s no. 3 book code. The British, American and Canadian convoy control systems were simultaneously experiencing problems of ‘shaking down’ into a routine of co-operation; the Royal Canadian Navy, which was undergoing an expansion from six to nearly 400 warships in service, the largest of any armed force in any country during the Second World War, found particular difficulty in matching the expertise of its larger partners. Since the outbreak of the war the Admiralty and the Royal Air Force had been locked in a quarrel over the deployment of long-range aircraft, the Admiralty rightly but vainly arguing that convoy protection produced a better return of effort than spectacular but often ineffective offensive bombing of German cities. Against this background Dönitz was working to extend the range of his U-boats by experimentation with refuelling at sea from submarine ‘milch cows’, and to equip his boats for the increasingly dangerous surface transit of the Bay of Biscay against attack by such long-range aircraft as the RAF did allocate to the Admiralty via Coastal Command. In the first half of 1942 Coastal Command aircraft mounting the new and powerful Leigh searchlight began to surprise U-boats in the Bay at night and attack them with depth charges. Two were destroyed in July, although Dönitz had already ordered that they must make the passage submerged, despite the delay entailed in reaching the Atlantic cruising grounds. The significance of the Leigh Light was that it gave aircraft ‘eyes’ in the final 2000 yards of their approach when radar did not work. In a see-saw of technical duelling, its usefulness was to be reduced when the Germans learned to develop passive radar detectors which indicated danger before the Leigh Light could be activated. Over the course of the Bay of Biscay battle, however, which lasted into 1944, the advantage consistently returned to the Allies. It was not until the deployment of the first schnorkel-equipped U-boats (which could recharge batteries while cruising submerged) in early 1944 that the danger levelled by anti-submarine aircraft began to be offset.

By then, however, the climactic phase of the Atlantic battle had come and gone. From July 1942 onward, when Dönitz at last achieved his target figure of 300 U-boats, he redeployed his effort to the central Atlantic, where the Allied escort fleet had been weakened by the transfer of British ships to help the Americans introduce convoy on the Eastern Sea Frontier. He was also now becoming more adept at organising patrol lines and concentrating wolf packs against convoys, and he was having greater success in locating convoys because of the advantage in cryptography that the B-Dienst currently enjoyed over Bletchley. The British responded with two experimental measures which would bear fruit later: the creation of a ‘support group’ of escorts to go to the rescue of a convoy under attack and the adaptation of merchant ships to fly off aircraft, the merchant aircraft carriers. The MACs however, proved clumsy forerunners of the true escort carriers, the first of which, USS
Bogue
, would not appear until the following March; while the persisting shortage of escorts would compel the 20th Support Group to be disbanded after two months.

As a result, U-boat sinkings in the North Atlantic in November 1942 reached the total of 509,000 tons, a figure exceeded only once before in the previous May, during the ‘Happy Time’ off the American coast. Vicious Atlantic weather halved sinkings in December and January; but in February 1943, despite continuing bad weather, 120 U-boats sank nearly 300,000 tons in the North Atlantic and the toll seemed set to rise. During March, in a running battle against two convoys eastbound from North America to Britain, codenamed HX229 and SC122, forty U-boats sank twenty-two out of ninety merchantmen and one escort of the twenty which were defending them. The tonnage sunk, 146,000 was the highest in any convoy battle and led Dönitz and his crews to believe that they had victory in their grasp. Altogether they sank 108 ships in the North Atlantic in March, totalling 476,000 tons, the majority lost in convoy. Wolf-pack tactics, supported by the position-finding and decrypting successes of the B-Dienst, appeared to have achieved mastery over convoy protection.

The appearance was illusory. Not only was the shipping replacement rate rising to meet losses (by October 1943 new construction had actually made good the amount of shipping lost since 1939, and built a superior merchant fleet into the bargain); U-boat losses were also beginning to equal launchings, at a monthly rate of about fifteen. Those statistics spelt doom to Dönitz’s effort. The explanation of the shift lay in several directions: Bletchley recovered its edge over the B-Dienst in May 1943, making rerouteing even more successful; escorts were becoming more plentiful, allowing the creation of permanent ‘support groups’, five in number in April; to the existing escorts were added two escort carriers embarking twenty anti-submarine aircraft which could force all U-boats in the vicinity of a convoy to submerge, thus effectively negating their offensive potential; improved radar, Asdic and depth-charge launchers (Hedgehog and Squid) levelled a direct tactical threat against the U-boat in close combat; but, above all, the increased availability of long-range patrol aircraft for the Atlantic battle wrought a strategic shift of advantage to the British-US-Canadian side. The long-range aircraft, particularly the Liberator bomber, equipped with radar, Leigh Light, machine-guns and depth charges, was flying death to a surfaced U-boat. In the Bay of Biscay – after a short and disastrous episode of ‘fighting it out’, ordered by Dönitz – the aircraft forced all U-boats to make their passage to the North Atlantic hunting-grounds submerged, at a fourfold time penalty; in great waters they completely disrupted Dönitz’s wolf-pack tactics by dispersing his patrol lines and savaging his concentrations wherever they appeared. In May 1943 U-boat losses, inflicted at a ratio of about 3:2 between aircraft and escorts, reached forty-three, which exceeded replacement more than twice. On 24 May Dönitz, accepting the inevitable, withdrew his fleet from the ocean, conceding later in his memoirs: ‘We had lost the Battle of the Atlantic.’

That did not mark the end of the U-boat war. In May 1944 the first schnorkel-equipped U-boat made its trial cruise. The schnorkel, a retractable air-breathing tube, allowed a submarine to cruise submerged while using its diesel engines. The device, invented by a Dutch naval officer in 1927, anticipated the development both of the closed hydrogen-peroxide system, which the Germans would bring into service in 1945, and of nuclear propulsion, in that it transformed the submersible U-boat into a true submarine, capable of operating below the surface throughout an operational mission. Misused, it could kill a crew by suffocation, and two U-boat crews are believed to have died in that way; properly employed, it would have revived the U-boat threat. Had the Germans not lost their main Atlantic ports to the American army in August 1944, schnorkel U-boats would have reopened the Atlantic battle, to the Allies’ very great cost.

Measured across the space of the Atlantic struggle, from September 1939 to May 1943, the cost can be seen to have fallen most heavily on Dönitz’s submarine arm. Although the Allies lost 2452 merchant ships in the Atlantic, of nearly 13 million gross-register tons, and 175 warships, mostly British (a term which included Canadian, Polish, Belgian, Norwegian and Free French escorts also), the
Kriegsmarine
lost 696 out of 830 U-boats dispatched on operations, almost all in the Atlantic, and 25,870 killed out of 40,900 crewmen who sailed; another 5000, plucked from the wrecks of their depth-charged boats, became prisoners. This casualty rate – 63 per cent fatal, 75 per cent overall – far exceeded that suffered by any other arm of service in the navy, army or air force of any combatant country.

The cost was certainly not in vain. Given that the economic odds disfavoured Germany from the outset, that its industry was organised ‘in breadth’ for a short war rather than ‘in depth’ for a long war, and that Hitler’s campaign of conquest was notably unsuccessful in adding either productive capacity or raw material resources to the Reich’s war-making capacity – it failed, for example, to acquire any large source of oil or non-ferrous metal ores for the German war machine – the delaying effect of the U-boat war on the transformation of Britain into an Anglo-American
place d’armes
for the eventual liberation of Europe may be seen as crucial. Moreover, while Germany fed itself easily between 1940 and 1944 from its own agricultural output and the requisitions made on farming in the occupied lands to the east and west, Britain was constantly held close to the level of minimum subsistence by U-boat depredations on its food imports. Rationing, though fairly applied and beneficial to the classes nutritionally deprived before the war, created a climate of latent crisis among the British which distorted and diminished their capacity to strike back at the enemy. Britain’s military threat to Germany during the Second World War was as intense as that levelled during the First though in relative terms Britain was not much weaker in 1940-4 than in 1914-18. It was the U-boats, marginally assisted by the Luftwaffe, which made the difference.

The U-boats were also to prove of crucial significance in diffusing and diminishing the support brought by British and especially American industry to their allies and their own ancillary theatres of war. Russian industry was devastated by the German invasion of White Russia and the Ukraine in 1941, and the Soviet Union’s capacity to sustain resistance was only salved by the almost incredibly swift transfer of factories from the western provinces to the trans-Ural regions in the terrible winter of 1941-2. Between July and October, for example, 496 factories were transported by train from Moscow to the east, leaving only 21,000 out of 75,000 metal-cutting lathes in the capital; overall the Russian railways moved 1523 factories from west to east between June and August, and between August and October it was calculated that 80 per cent of Russian war industry was ‘on wheels’, moving from the threatened zones to areas of safety in western or eastern Siberia. The disruption of production entailed by this unprecedented industrial migration could only be made good by substitutions from Western sources, of weapons and munitions but above all of the elements of war’s infrastructure – vehicles, locomotives and rolling stock, fuel, rations and even such simple but vital supplies as boots, the felt winter boots for lack of which tens of thousands of German soldiers lost toes in the winter of 1941-2. Between March 1941 and October 1945 the United States supplied the Soviet Union with 2000 locomotives, 11,000 rail wagons, nearly 3 million tons of gasoline, 540,000 tons of rails, 51,000 jeeps, 375,000 trucks and 15,000,000 pairs of boots. It was in American boots and trucks that the Red Army advanced to Berlin. Without them its campaign would have foundered to a halt in western Russia in 1944.

Boots and trucks proved far more important items of war supply than the 15,000 aircraft, 7000 tanks and 350,000 tons of explosives which Lend-Lease also consigned to the Soviet Union; far more important than all the aid sent by Britain during the course of the war – 5000 tanks, 7000 aircraft, even the 114,000 tons of rubber. Vital though these war supplies were, however, they reached Russia between 1941 and 1944 by the most circuitously inconvenient routes, thanks to Dönitz’s U-boat campaigns. The ‘North Russia run’ from Britain to Murmansk and Archangel had to be routed almost as far west as Greenland and as far north as Spitsbergen (on which a strange little sub-war for possession of weather stations was fought in 1941-2) during the summer months of 1941-4, to avoid air and sea attack by German units based in Norway; when the winter ice drove the convoys eastward, losses rose grievously, forcing Churchill to interrupt sailings on several occasions – to Stalin’s woundingly expressed scorn. The alternative route through the Persian Gulf was roundabout and terminated at the railhead of a long and inadequate railway system. The Pacific route, to Vladivostok, was also affected by ice and the danger of enemy attack, and it connected with the wrong end of the longest railway line in the world, the Trans-Siberian.