By late 1941 to early 1942 as a result of an increase in the defensive armament carried by enemy shipping, the low-level, lateral attacks mounted by the Fw 200s of KG 40, which had proved so successful earlier, had become increasingly unsustainable, initially against convoys, but soon even against single vessels. Nevertheless, though their efforts were muted to some extent, and some aircraft were moved away from France, the Condors were still able to perform occasional valuable reconnaissance for the U-boats so that they could be directed towards targets.25
Aside from the Fw 200s, the only aircraft of any range available to the Fliegerführer Atlantik were the Ju 88s of Kü.Fl.Gr.106, which could be deployed only against convoys off the eastern coast of Britain. Even these operations eventually passed to the control of IX. Fliegerkorps, and, between July 1940 and December 1943, the bomber units of that Korps claimed 42 vessels sunk totalling 167,000 GRT, 38 vessels of 171,000 GRT probably sunk and 118 vessels damaged, totalling 439,000 GRT.26
The Fliegerführer Atlantik was then confined to operations off the south and western coasts of England, but in May 1942 BdU again requested assistance to provide cover for U-boats as they transited in and out of the Bay of Biscay and to repulse enemy anti-submarine aircraft. For the rest of 1942 and early 1943 this became the main function of the Fliegerführer Atlantik and its small number of twin-engined fighter Gruppen.27
The historian John Terraine asserts that the U-boats ‘were at the very height of their powers in the Atlantic’ in May and June 1942, and this despite appalling weather, which saw gales and dense fogs in mid-summer.28 But Dönitz was aware that, increasingly, the boats were being captained by untested commanders and raw crews amidst steadily more challenging conditions.
The bad sentiment between the Kriegsmarine and the Luftwaffe continued to fester in early June 1942 when, after the RAF had managed successfully to reconnoitre German naval ship positions off Norway, conversely, the Luftwaffe proved incapable of performing any level of acceptable ‘counter-reconnaissance’. Raeder’s staff mocked the latter for its apparent inability to conduct even the ‘fundamental requirements of any sort of naval warfare.’29
Out at sea at this time, one of Dönitz’s tactics was to endeavour to locate a convoy before it entered the ‘Greenland air gap’ and to attack it as it was crossing those ‘unprotected’ waters. As the convoy re-emerged from the gap, so the U-boats would then withdraw. Another tactic, which was deployed in October 1942, was to position two ‘packs’ of boats on the departure side of the air gap and to lie in wait.30 Yet the need for ‘eyes’ was becoming ever more urgent. On 13 July 1942, 970 km west of Ireland, the wolfpack of nine boats led by inexperienced captains located a convoy, but then lost it. For three days, they searched – fruitlessly.31
By mid-1943, U-boats would attempt to move ahead of a convoy in order to attack while submerged if they were unable to do so on the surface. They would also try to exploit the disruption caused by a first attack, with one boat often following another from the same direction two or three kilometres behind.32 A Luftwaffe report from April 1944 described in detail how U-boats formed for reconnaissance, and the weaknesses arising from such tactics:
The best formation for reconnaissance is the ‘Reconnaissance Line Abreast’ formation, in which the largest possible number of U-boats is, with a necessary sacrifice of formation in depth, placed next to each other with their areas of vision overlapping. In this way it is possible to cover comparatively large sea areas. It is occasionally possible, however, that a convoy can slip through this reconnaissance strip [patrol line] at night. To avoid this, the whole strip moves to and fro so that, in all probability, it will sight the convoy moving along its estimated route by day. This means that at night the strip must move on the estimated course of the convoy at a speed designed at all costs to keep it ahead of the convoy.
Paradoxically, most U-boat commanders preferred to attack at night, despite the threat posed by radar and enemy methods of illumination.33 The report continued:
This strip formation may sound very advantageous in theory; in practice, however, gaps will appear in individual strips through inaccurate navigation. In bad visibility, fog, rain or storm, the situation may become even worse. It is thus possible for a convoy to slip through the line or discovering its presence in the vicinity, to avoid it all together by a wide detour. It is not difficult to realize how small an area a strip of 25 U-boats can cover compared with the area in which convoys move. Clearly it is possible for a convoy to avoid interception, even without taking advantage of poor visibility.
Our policy in U-boat warfare is only to attack a convoy where a large number of craft is available for the assault, the aim being to destroy the core of the enemy, i.e., the valuable merchant vessels, by penetrating the escort forces in a simultaneously launched mass attack with the largest possible number of U-boats.
However, in order to put theory into practice, it was recognized that such a concentration of U-boats could be assembled only by ‘flawless shadowing’ of a potential target. But shadowing from the sea brought its own difficulties; convoys invariably adopted counter-measures – zigzagging their courses at regular intervals of between three and 15 minutes by up to 20°, so that the fixing of a mean course was extremely difficult. In addition a convoy would endeavour to shake off a shadower by wider alterations of course, usually at dusk. In hours of daylight, a surface shadower had to remain just within sight to be able to observe the convoy and yet remain undetected. If it was spotted, the convoy escort would make all effort to force the U-boat to dive, where submerged, it became much slower than the target.
The Luftwaffe believed that, ‘the disadvantages suffered by the U-boat of low eye-level, short-range of vision and lack of mobility do not apply in the air … The Luftwaffe is in a position to cover the wide spaces of the Atlantic and to survey all shipping movements. The task of air reconnaissance is therefore to find a target, report it, shadow it and direct the U-boats to it … By means of coordination it will be possible to create the most favourable conditions for the attack, and without serious losses, to inflict the heaviest damage on the enemy.’34
Certainly by the early autumn of 1942, Dönitz was expressing his envy of the Allies’ long-range reconnaissance aircraft. ‘In the Atlantic,’ he wrote, ‘the enemy’s daily reconnaissance forces us to dispose U-boats far out in the centre of the ocean … There are also some aircraft of particularly long range which are used as convoy escorts. They have been met 1300 km from British bases.’35
However, the early autumn of 1942 was a difficult time for the British; many convoys were slow and these always suffered greater losses, usually of some 30 per cent, than the faster ones. There was an urgent need for more escorts, particularly destroyers, of which there was a grave shortage.36 This shortage, as well as a lack of available fuel, meant that the convoys had to maintain the shortest route across the Atlantic (the Great Circle). This worked in the favour of the U-boats.37
In October 1942, the Germans had 196 boats operational.38 Between August and December 1942, 54 U-boats were lost, of which 26 succumbed to attack by aircraft.39 It was a grim business. When a boat was depth-charged, the effect was often total, as one account described: ‘Over the place of the explosion, gathering slowly from the depths beneath, was a nasty, oily litter of timber, clothing, pocket books, cigarettes, food packages and bits of human flesh which immediately attracted the attention of the wheeling gulls.’40
That autumn the weather turned for the worse. U-boats, merchantmen and their escorts struggled with it, the U-boats seeking relief from the endless buffeting and crashing of the waves by diving below the angry surface. In these conditions, the contribution of long-range aircraft from either side would have been folly. Yet, despite the weather, of six attempts to attack convoys in October, although two failed, in three of them, the U-boats accounted for the sinking of 30 merchant ships.
At the beginning of 1943, the Allies recognized that the battle in the Atlantic would b
ecome a ‘deadly, ruthless series of fights, in which no mercy would be expected and little shown.’41 They had good cause to think this; in 1942 the U-boats had sunk 1,160 ships totalling 6,266,215 tons in all waters.42 The weather would also continue to show no mercy: winds howled at up to 250 km/h, bringing, as one U-boat man remembered, ‘driving snow, sleet, hail and frozen spray. It cut our faces like a razor, and threatened to tear away our eye masks; only the steel belts around our waists secured us to boat and life.’43
The bad weather in the early new year saw the number of vessels sunk by U-boats reduce to 37, totalling 203,123 tons. Yet the Luftwaffe believed that it was not weather that was responsible for the decline, but rather that the unfavourably positioned reconnaissance patrol lines of U-boats were simply unable to prevent no fewer than seven convoys from ‘slipping through the net’. According to Luftwaffe analysts, this was an ‘outstanding example of the effect of inadequate reconnaissance reports on the figures of enemy shipping losses. It is evident that considerable damage might have been inflicted on enemy shipping if, with the aid of air reconnaissance, it had been possible to concentrate all U-boats in that area, and thus to make the fullest use of our whole U-boat strength.’44 For the Luftwaffe, this was a curious comment; it is nothing short of an admission of failure to respond to naval requirements.
As an example, the Falke pack of 14 U-boats had been formed in January south-east of Greenland to strike at North and Outbound North (Slow) convoys, and from where it formed a line stretching beyond the range of Allied aircraft based on Iceland. The conditions were atrocious and one boat, a new Type IXC40, U-167, was battered by thunderous seas which damaged its bridge, threw a crew member overboard, injured the commander and forced the boat to abort and return to France. Also in the Falke group was the new Type VII, U-632. This boat was spotted on the surface by a British-crewed B-17, which dropped depth charges from 80 ft and damaged it. Despite this, the Falke pack searched fruitlessly for days for a westbound convoy. In the end it achieved nothing. In Berlin, Konteadmiral Eberhard Godt, Chief of BdU Operations, commented in his war diary that U-boats were ‘totally unsuitable’ for finding convoys. Such a task required many U-boats and many wasted days searching. What was needed was long-range search and shadowing aircraft: ‘If we had aircraft the war would be very different.’45
Dönitz succeeded Raeder as Commander-in-Chief of the Kriegsmarine at the end of January 1943 and was promoted to Grossadmiral, but he also remained in command of the BdU with his HQ brought from France to the Hotel am Steinplatz at Charlottenberg in Berlin. He told his staff: ‘The sea war is the U-boat war.’46
On 26 February 1943, Dönitz travelled to the Führerhauptquartier Werwolf at Vinnytsia in the Ukraine. There, he and Hitler pored over large maps, studying what distant areas could be covered by various types of long-range aircraft. Hitler had been informed by Göring that the construction of such aircraft would be given priority, but he remained sceptical over the prior ‘illusory’ promises of the Reichsmarschall. Dönitz explained to the Führer that no enemy shipping had been sunk over a 14-day period that month, because ‘nothing was sighted’. Whilst this may have been attributable to weather and poor visibility, or possibly the enemy’s actions in locating the U-boats, Dönitz cited the primary cause as being the complete absence of Luftwaffe reconnaissance.47
Indeed the Luftwaffe admitted that in late 1942 to early 1943, ‘the absence of air reconnaissance was the sole reason why the full force of our U-boats could not be brought to bear on a sighted target, and why they often returned to base after an abortive trip still fully armed with torpedoes; and this at a time when the loss of every single freighter was keenly felt by the enemy.’48
On 5 March 1943, the Reichsluftministerium (RLM – the Reich Air Ministry) had held a conference in Berlin on transatlantic and long-range aircraft. It was attended by Oberst Karl-Henning von Barsewisch, the General der Aufklärungsflieger, and Oberstleutnant Theodor Rowehl, the commander of the Versuschsstelle für Höhenflug (Test Station for High-Altitude Aviation). Von Barsewisch remarked:
It seems from what was said in the talk with Dönitz [and Hitler] that the U-boat war stands or falls by reconnaissance aircraft. This has been explained to the Führer, he has approved it and the Reichsmarschall has promised to fulfil the request. Undoubtedly, we must have a reconnaissance aircraft which can match the demands for mid-Atlantic cover.49
In von Barsewisch’s view, Dönitz and the Seekriegsleitung (SKL – Maritime Warfare Command) regarded the four-engined Messerschmitt Me 264 (see Chapter Fourteen), and later, the proposed Ta 400 from Focke-Wulf, as more preferable aircraft with which to conduct long-range maritime reconnaissance missions than the existing Bv 222 flying boat. His opinion had probably been influenced by the failure of refuelling trials with the Bv 222 involving U-boat tankers. Dönitz’s problem was that the Ta 400 was not expected to appear before 1946, and thus for the foreseeable future, the Kriegsmarine would have to rely on the Junkers Ju 290 and possibly Ju 390, and Heinkel He 177 bomber to provide interim maritime reconnaissance capability.50 Yet it would not be until 3 May that the SKL noted that the Luftwaffe had finally decided to ‘plan for a long-range reconnaissance aircraft suitable for Atlantic missions.’ Generalfeldmarschall Milch and Generaloberst Hans Jeschonnek, the Chief of the Luftwaffe General Staff, were agreed that the Me 264 was unlikely to make its operational debut before 1944 or even 1945, and a number of technical experts were instructed to explore urgently the possibility of fitting auxiliary tanks to the Me 264 to increase range still further.
By March 1943, the U-boat arm had just about reached the strength which Dönitz had hoped it would back in 1939.51 That month it sank 108 ships of 627,377 tons giving the Grossadmiral some reason for cheer.52 Also, between 1 March and 22 April 1943, the Luftwaffe managed to maintain daily reconnaissance operations over a sea area from 38° to 49° North and 10° to 20° West, often involving six aircraft, which observed approximately four million tons of merchant shipping and warships totalling about 300,000 tons, and during which period convoys moved within the effective range of German long-range bombers for at least four to five days. During these six weeks, according to a report of January 1944, the irony was that the Luftwaffe was unable to mount a concentrated attack against enemy merchant shipping because of the ‘predominance of reconnaissance operations for Marinegruppe West!’53
That spring, the Luftwaffe noted, ‘the enemy provided his convoys from Britain to Gibraltar with air cover in addition to moving them further and further out of range of the Fw 200. New location equipment and methods made U-boat operations more difficult.’54
Indeed, for the Germans, a worrying new dimension now made its debut over the Atlantic in the form of American-built B-24 Liberator Very Long Range (VLR) anti-submarine aircraft. To patrol the Atlantic, RAF Coastal Command had initially operated a mix of single- and twin-engined biplanes and monoplanes including Avro Ansons, Lockheed Hudsons, Vickers Vildebeests, Saro Londons and Supermarine Stranraers. These were augmented by the Short Sunderland and Consolidated Catalina flying boat and, later, Vickers Wellingtons, Handley Page Halifaxes, Armstrong Whitworth Whitneys and Boeing Fortress Is. But on 17 March 1943, a Liberator flew for nearly nine hours from its base in Northern Ireland to reach a convoy. On its way, it had attacked a U-boat, forcing it to remain submerged for most of that day. The aircraft then attacked another boat with similar effect. When it returned to base, it had been in the air for 18 hr 20 min.55 The Liberators would soon be joined by radar-equipped Wellingtons and Halifaxes. John Terraine succinctly describes the effects of the appearance of aircraft as being ‘especially nerve-racking for [U-boat] crews returning from hard actions in mid-Atlantic, perhaps with damage or injured men aboard. This pressure on morale, at times when it would normally be expected to ease, is a factor in the battle that is not to be ignored.’56
The Allies were now able to extend their air cover from flying boats and land-based bombers to just about any point in the Atlantic n
orth of 45° North, though this scope faltered when it came to the sea north of the Azores, and so Dönitz next ordered his boats to move farther west into that area.57 But it was a game of cat and mouse; of 174 scheduled North Atlantic convoys, 105 were rerouted so that they were not sighted by the U-boats.58 However, the British had recognized in April 1943 that the wolfpacks could no longer be evaded by simply rerouting convoys; as Winston Churchill has recorded, ‘The issue had to be fought out by combined sea and air forces round the convoys themselves.’59 This meant air–sea cooperation.
The escort groups had been strengthened, and were operating on a more sophisticated basis, as well as benefitting from more escort carriers, which brought, in addition to VLR aircraft, naval fighters. The Atlantic air ‘gap’ was closing and this meant nowhere was safe for U-boats to attack without the threat of attack from aircraft. Fifteen U-boats had been lost in March and 15 more in April, and morale among the crews was beginning to suffer, yet by the end of April there were 193 boats in the West, and more boats than ever before were operating on the North Atlantic convoy routes.60
But in May, Dönitz had come to realize just how great Allied sea and air dominance was, as 41 boats were lost in that month. He decided to pull his boats out of the North Atlantic ‘using the utmost caution’ to an area south-west of the Azores. ‘We had lost the Battle of the Atlantic,’ he wrote.
On 31 May 1943, Dönitz had a meeting with Hitler at the Berghof at which the Führer agreed fully with the Admiral’s contention that even by that stage of the war, it was not too late to start building long-range aircraft suitable for cooperation with the U-boats. Dönitz further put forward the case for more specialist U-boat cooperation training with the Luftwaffe. He reasoned that naval aviation crews should spend four to five months at sea, be trained in celestial navigation, drift computation, convoy-shadowing tactics, detection-finding signalling, liaison with other aircraft at long-range and other forms of communication. Such training should take place alongside U-boat crews, with the training flotilla in the Baltic Sea. According to the record of the meeting, Dönitz stressed the following:
Shadow over the Atlantic Page 3
