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The Battle of the Atlantic, 1939-1945
A Decisive Campaign
What Churchill called ‘The Battle of the Atlantic’ was, like the so-called Battle of Britain, one of the war’s decisive campaigns and lasted for as long as Hitler’s war. Without command of the sea, the Anglo-American land and air campaigns could not have been mounted or sustained. Without pressure on the Germans from the west and seaborne aid, Soviet successes in the east would have been harder to achieve. Yet in November 1940 Churchill told the Defence Committee (Operations) that, in his view, the Admiralty was making ‘extravagant demands’ for aircraft at a time when it was essential to strengthen Bomber Command. He thought the navy was not making the best use of its Fleet Air Arm (FAA). The whole matter of assignment of forces must be considered jointly by the Admiralty, the Air Ministry and the Ministry of Aircraft Production. He then recalled, wrongly, that the RNAS had expanded so greatly during the Great War that the Royal Flying Corps was left dangerously short of men and materials.
The demise of the RNAS in 1918 had long-lasting consequences. Even after the FAA returned to the Royal Navy in 1937, naval aviation remained ‘tactically and technologically backward’ compared with the United States and Japan. This was because the loss of the RNAS cleared a path to the top for single-minded sea dogs such as Dudley Pound and Tom Phillips. As assistant chief of Naval Staff in 1928, Pound suggested that ‘convoy would be the wrong strategy to adopt in another war because it exposed shipping to attack from surface raiders, which he saw as the primary threat’. He had forgotten the important role aircraft and airships had performed in the Great War. So too had his close friend Tom Phillips, who ‘simply refused to comprehend the potential of air power over the sea’.
Between the wars, as Phillip Meilinger wrote, Coastal Command was an ‘unwanted stepchild’ of the Royal Navy. As a result, it was years before its Sunderlands and Beaufighters were supported by such efficient American types as the Hudson, Catalina and above all the Liberator. Not until 1943 did naval airmen have the aircraft, the equipment and the tactics needed to overcome the U-boat menace.
The British only began to use Ultra to help route convoys in June 1941, but they used it effectively until February 1942. Karl Doenitz suspected that the Allies were reading his radio messages to U-boats, but his experts assured him that that was impossible. A blackout of U-boat cyphers that began in February 1942 lasted for ten months and pacified his doubts. Fortunately, he lacked sufficient U-boats in 1939-1941 to achieve a decisive victory. The crisis in March 1943 is well known, but the ‘air gap’ was the main problem, wrote Marc Milner, and the ‘singularly decisive influence of air power on the Battle of the Atlantic was well understood at the time, at least by sailors’. Long-range aircraft were essential. ‘Submerged U-boats, driven down by aircraft, lacked the speed, range, endurance and tactical effectiveness to tackle convoys in the broad ocean.’
Slessor and Churchill
In October 1942, Jack Slessor, assistant CAS (Policy) in the Air Ministry, was told that he was soon to take over Coastal Command, even though he knew nothing about the war at sea and the difficulties in combining British, American and Canadian resources in the air or in the water. He was, however, well served by his staff and in December 1942 code-breakers at Bletchley Park broke into the latest version of the Enigma machine, so that by the time Slessor took command in February 1943 he and his colleagues were being accurately and promptly informed about Doenitz’s intentions and the location of his U-boats.
As for Churchill, so fulsomely praised by Slessor, he had little to say about Coastal Command. Its achievements were not dramatic enough for his boyish taste. ‘I could not rest content with the policy of “convoy and blockade”’, he admitted in his memoirs, when in fact the escorted convoy proved to be the most effective means of overcoming the U-boat in both world wars. After the war, it was supposed that the so-called ‘hunter-killer’ groups of aircraft carriers and surface vessels had been the U-boat’s deadliest foe. In fact, of the 770 German and Italian boats sunk at sea by Allied action, only twenty were destroyed by those groups as compared to more than 250 by aircraft alone. Yet Slessor, devoted to what he thought of as offensive action, constantly pressed for more and stronger hunting groups in the Bay of Biscay. However, he did co-operate fully with Admiral Sir Max Horton, at ‘Western Approaches’, based in Liverpool, who was responsible for all North Atlantic convoys.
The Atlantic campaign, waged by two services (the RAF and the Royal Navy) and three nations (Britain, the United States and Canada) was one enormous battlefield, stretching from the Hebrides to Halifax in Nova Scotia and from Casablanca to the Caribbean. ‘One shudders to think,’ wrote Slessor, if the Germans had built up ‘their really decisive arm, the U-boat service,’ before the war, instead of wasting resources – human and material – on a ‘third-rate heavy ship force’. Churchill thought so too. ‘It would have been wise for the Germans to stake all upon it.’ Even in the last two months of the war, U-boats sank no fewer than forty-four Allied ships.
Inter-Service Rivalry
After Pearl Harbor, the Americans suffered unnecessarily heavy losses to U-boats along the east coast as a result of poor equipment, strained relations between the navy and the army and civilian reluctance to accept that ‘business as usual’ must be interrupted. ‘The violence of inter-service rivalry in the United States in those days had to be seen to be believed,’ wrote Slessor, ‘and was an appreciable handicap to their war effort.’ John Buckley agreed. Anglo-American air co-operation over the Atlantic in the years 1942-1943 was ‘a catalogue of mistrust and suspicion’; logical procedures were passed over simply because they would have required a degree of co-operation that not even the influence of Roosevelt and Churchill could impose.
On the British side, Slessor resisted strengthening Coastal Command at the expense of Bomber Command, but it was the acquisition of a small number of very long-range B-24 Liberators that would close the ‘Atlantic Gap’ and prevent the U-boat from cutting supplies to Britain and troops from the United States and Canada to prepare for Operation Overlord.
Closing the Gap
Churchill and Portal supported Harris for too long in his reluctance to regard the Battle of the Atlantic as vital. The ‘slavish adherence’ (in Buckley’s words) of Churchill and the Air Staff ‘to the principles of the strategic bombing offensive seemingly blinded them to the harsh realities of the Battle of the Atlantic’. They opposed the allocation of long-range aircraft to Coastal Command, even though Pound had rightly said in March 1942: ‘If we lose the war at sea, we lose the war.’
The failure of the Allies to close the Air Gap before 1943 ‘remains one of the great unsolved historical problems of the war’. The answer lies in the fact that most B-24 Liberators (by far the most effective weapon) were assigned either to the American bomber offensive over Europe or patrol in the Pacific. Yet only about forty to fifty Liberators were needed to close the gap permanently. ‘For many historians of the Atlantic war the myopia of the airmen who drove the strategic bomber offensive seems incredible’, and yet that offensive depended upon securing the Atlantic.
The Atlantic victory, wrote Slessor in May 1943, meant that ‘many of us could be spared to take part in the more direct offensive against objectives in German and Italian soil’. To tell men who had just achieved a decisive victory that they might now ‘be lucky enough to take part in the real work of the war’ confirms Terraine’s opinion that Slessor simply did not understand what was at stake in the Atlantic. A committed bomber believer, he regarded the proposed Overlord operation with deep suspicion, convinced that Harris was conducting ‘true air warfare’, that would bring victory without an invasion.
It would not be until March 2004, nearly sixty years after the end of the war in Europe, that Coastal Command received its first national monument, unveiled by the Queen in Westminster Abbey, to commemorate nearly 11,000 men who lost their lives in some 2,000 aircraft. But they accounted for nearly 200 U-boats and another twenty-four in joint action with surface vessels. ‘Constant Endeavour’ was indeed a fitting motto for that command.
At the end of the Great War, the RAF had more than 600 aircraft in home waters engaged in opposing U-boats, but it would not be until the third year of the next war that the Air Ministry assigned enough aircraft to mount a serious challenge to a renewed U-boat threat.
Harris had assured Churchill in June 1942 that Coastal Command was ‘merely an obstacle to victory’: a foolish remark even by Harris’s standards and one that Churchill did not contradict. Harris, wrote Sebastian Cox, ‘did not explain how the population, including his aircrews, were to be fed, or his aircraft fuelled, if the U-boat war was lost’. Here, as so often, Harris ‘would have done better to eschew hyperbole’. Until 1941, that command had been virtually powerless, with neither the aircraft nor the weapons needed to challenge U-boats.
By 1943, wrote Slessor, the decisive air weapon was the Mark XI Torpexfilled depth charge, dropped in sticks of four to eight at very low levels. By mid-1941, possession of fuelling bases in Iceland made continuous surface escort across the Atlantic possible, but Liberators were needed to close the gap in air cover. A three-cornered struggle between the US Army and navy air forces and Bomber Command went on until 1943 when at last Coastal Command’s claim was admitted: ‘It surprised everyone to see how few of these splendid machines were sufficient to tip the scale. In mid-May, an attack by thirty-three U-boats failed to sink a single merchant ship and at the end of that month Doenitz admitted that the battle was lost. But Slessor, among others, regarded it as a defensive victory. As devout Trenchardists, they pined for what they regarded as offensive action, quite overlooking the fact that overcoming U-boats was an essential task: unless that were done, there could have been no landings in Normandy.
The Leigh Light
Twin-engined Vickers Wellington bombers, equipped with what became known as the ‘Leigh Light’, played a significant part in the battle from June 1942 onwards. Inventor Wing Commander H. de V. Leigh had flown anti-U-boat patrols in 1917 and 1918. He returned to the RAF in 1939 and served at Coastal Command HQ under Frederick Bowhill, who had been his squadron commander in 1917. In September 1940, Bowhill asked his staff for ‘bright ideas’ about how to destroy U-boats at night. Air-to-surface vessel (ASV) radar was no help at night, which was when U-boats surfaced to recharge their batteries. At Leigh’s suggestion, a searchlight was installed in the mid-upper turret of a Wellington in March 1941, but it was not until June 1942 that the device became effective over the Bay of Biscay.
Inadequate Co-operation
Early in 1939, Doenitz had said he would need 300 U-boats to isolate the British Isles. At that time, he believed: ‘Aircraft can no more eliminate the U-boat than a crow can fight a mole.’ He was proven wrong. Luckily for Britain and the United States, he had always ‘lacked eyes’: reliable long-range aircraft.
The four-engined Focke-Wulf Fw 200 Condor, a converted airliner, had been pressed into service in 1940, but it was not robust enough for hard service over the sea. In any case, there were few of them: only 252 were built between 1940 and 1944. Had the Germans developed a more effective machine for co-operation with U-boats – an aircraft as robust as, for example, the Short Sunderland – and built them in far greater numbers, their impact would have been even graver on Atlantic shipping. But Goering, the war’s most inept air commander, had no grasp of what modern aircraft might achieve and refused, in any case, to co-operate with the navy. Hitler took little interest in the war at sea and never pressed him.
Unwise Faith in ASDIC
In 1937, the British Admiralty decided that the U-boat would never again threaten shipping, thanks to ASDIC, a sonar device. These so-called experts quite overlooked the fact that ASDIC could not detect U-boats on the surface, where they spent most of their time. Using their diesel engines, they were faster than most merchant ships and usually attacked during hours of darkness. Using their electric motors, when submerged, they could move only slowly and not for long.
The Admiralty, forgetting its Great War experience, decreed that U-boats should be hunted; a satisfyingly offensive task, even though few were caught. In fact, they were usually to be found close to convoys of merchant ships. Not until 1943 did Coastal Command get the equipment it needed: long-range aircraft; bombs; depth charges and air-to-surface vessel radar. At every step of the way it had to fight the Admiralty for effective air-sea co-operation. It was also bitterly opposed by Bomber Command and most members of the Air Staff who remained fixated on the bomber as a war-winning weapon. Victory, far too long delayed, came only in May 1943, when no fewer than forty-one U-boats were sunk and Admiral Karl Doenitz admitted defeat.
Portal’s Failure
In February 1941, Portal complained to Richard Peirse (his successor as head of Bomber Command) that the RAF was ‘on the defensive with a vengeance owing to the situation in the Atlantic’, adding that ‘a very high proportion of bomber effort will inevitably be required to pull the Admiralty out of the mess they have got into’. These were astonishing words from an airman with such a high reputation.
It is generally agreed that Hitler caused the ‘mess’, helped along by British and French politicians, and that British bombers only began to harm Germany in 1942. It is not easy to understand how Portal could regard the war at sea as an annoying distraction from what he thought of as ‘the real war’ in the skies over Germany. The Admiralty was largely responsible for the weakness of its FAA, but Portal certainly knew how poorly equipped Coastal Command was. Early in March 1941, Churchill – not Portal – directed Bomber Command to devote its attention to ‘defeating the attempt of the enemy to strangle our food supplies and our connection with the United States’ by attacking U-boats at sea, in docks and in building yards and by attacking German bombers used against shipping.
The most dangerous failure in Churchill’s conduct of the naval war was his refusal to back the navy’s demand (supported by Coastal Command) that long-range aircraft be diverted from Bomber Command in 1942. The pigheadedness of Portal, combined with Harris’s tunnel vision came close to losing the Battle of the Atlantic. The U-boat threatened to bring British industry to a standstill, ground Bomber Command for lack of fuel and prevent the possibility of an Anglo-American liberation of the Continent. ‘Here was the absolute crux,’ wrote Barnett, ‘of Britain’s war against Germany.’ Harris never understood this and Portal accepted it, only reluctantly.
The Channel Dash
In February 1942, Hitler decided that three powerful warships, accompanied by destroyers, mine-sweepers and torpedo-boats, must leave Brest, on France’s Atlantic coast (where they had been regularly attacked), and sail through the English Channel to greater safety at Wilhelmshaven in Germany. They would have ample air cover for most of their journey. This ‘Channel Dash’, as the British called it, like many German operations, ‘was a tactical success but a strategic failure’: at Brest, the ships were a standing threat to trans-Atlantic convoys; at Wilhelmshaven, they could more easily be contained and did nothing useful before they were destroyed.
At the time, however, on the eve of the surrender of Singapore, and with Operation Crusader having failed in North Africa, it was a severe blow to all Hitler’s opponents. The three services had not worked together, and performed poorly separately, failing to use reliable intelligence for fourteen hours after the Germans had left Brest. There was plenty of courage, as so often in these early years of the war, but efficient use of ample resources was sadly lacking. While Germany rejoiced, in Britain ‘the sense of national shame was profound... Churchill was taken aback by the scale of popular anger; it seemed that by this stage of the war, while the British public was inured to a seemingly unbroken run of defeats on land, it was not prepared to accept humiliation in a domain that it considered to be its birthright.’
Overcoming the U-boat
March 1943 saw ‘the rock bottom of Allied fortunes; a twenty-day period in which ninety-seven ships (over 500,000 tons) were lost’: it was the period in which Germany came closest to severing links between Britain and the United States. As so often in the Second World War, the Allies were greatly helped by their enemies. For example, the commanders of the German navy had preferred battleships to U-boats and consequently not enough of these far more dangerous weapons were built.
Goering used his immense influence to prevent the development of long-range patrol aircraft, capable of working with U-boats; in 1941 and 1942 Hitler diverted too many U-boats to the Arctic and the Mediterranean, where their successes were less valuable than they would have been in the Atlantic. As in other theatres, the Germans were too confident in the security of their wireless communications.
Yet by the end of May 1943, the Allies had achieved a decisive victory over the U-boats. A turning point came with the successful defence during four days, 4-7 April, of Convoy HX 231, sailing from Newfoundland for Britain. Warships under Commander Peter Gretton, aided by long-range B-24 Liberator bombers, all of them helped by code-breakers and radio direction findings were responsible.
Only three of the sixty-one merchant ships making up the convoy were lost and Liberators sank two of the twenty U-boats that attempted to attack them. Gretton later reported that ‘air cover again showed itself to be the key to this problem’. Time and time again, Liberators intercepted U-boats at a distance from the convoy, causing them to dive and so lose contact with their targets. Ultra information was of great value, but not in itself decisive.
In September 1941 – three months before Hitler’s declaration of war – Roosevelt had publicly ordered the US Navy to attack German vessels on sight. The D-Day landings and the Battle of Normandy were, in Terraine’s opinion, ‘the supreme offensive action of the Western Allies in the war, their great contribution to the defeat of Germany’. The victory in the West could not have taken place without the victory in the Atlantic.
John Ferris argued that Ultra has been over-praised in the years since the secret was revealed for its part in the Allied victory in the Battle of the Atlantic. That battle, in fact, was won by Allied shipyards, ‘not by steel-eyed naval captains’, brave and skilful as they were, but by ‘four-eyed cost accountants’. The U-boat never came close to sinking enough merchant ships to prevent American men and materials from crossing the Atlantic. Ultra certainly helped greatly in enabling shipping to avoid U-boats, but other sources of intelligence, notably direction-finding, were important. Long-range aircraft and centimetric radar aboard convoy escorts were equally vital.
