Winning the Battle of the Atlantic: 1943

By Zoë C. Vince

This article aims to explore the various contributing factors to Allied successes in March to May of 1943.  Although the Atlantic continued to be a major theatre of operations until the end of the Second World War, it may be argued that the threat posed by German U-Boats had been greatly diminished by Allied efforts in the spring of 1943.

This author will argue that despite a variety of elements of the anti U-boat war, from intelligence to technology, combining to facilitate the withdrawal of U-boats from the North Atlantic in May 1943, it was in particular the developments in training and organisation of the Allied convoy system which can be most directly linked to German failures in this period.


The successful application of Allied tactical and technological advancements to anti-submarine warfare, culminating in the spring of 1943, lead to a turning point in the Battle of the Atlantic.  Combating the U-boat threat required close co-operation between the Allies, integrated inter-service training and command, and co-ordination of tactics, procedures and technologies.  Although there are a number of factors which contributed to Dönitz’s withdrawal of the U-boats in May 1943, it was the organisation of the convoys, support and escort groups by Admiral Sir Max Horton, and the training of crews specifically in anti-submarine warfare which provided the cohesion and professionalism required to both prevent U-boats sinking ships in convoy and simultaneously destroy a comparatively high number of submarines.  The superior standard of efficiency achieved by the Allies, in all aspects of the anti-submarine battle, ensured that the German U-boats ceased to pose a serious threat in the Atlantic.  It is clear, therefore, that training and organisation was an extremely important factor.

While addressing this subject, it would be impossible to list and discuss Allied training and organisational developments in isolation without acknowledging closely related elements of the anti-submarine campaign such as technology, signals intelligence and air power.  This article will seek to argue that while these complementary factors contributed to the Battle of the Atlantic to varying degrees, it was the improvements in training and organisation of the convoy system which enabled the effective co-ordination and optimum usage of all related developments.

The Atlantic theatre of naval operations remained important throughout the war, indeed a contemporary naval officer stated that without Allied success in this theatre “the grand conception for the liberation of Europe might never have materialised”.  Among historians there is a consensus that May 1943 marked a turning point in the Battle of the Atlantic.  Earlier historiography including the British and US naval histories described a crisis occurring in March 1943, with communications from the old world to the new coming under severe threat, followed by the sudden and unexpected collapse in May of the U-boat campaign.  Revisionist research into this subject, while acknowledging the importance of May 1943 as a pivotal month in the Battle of the Atlantic, has generally disputed the traditional view of crisis, stressing that while certain Allied convoys suffered great losses in March and April many others suffered none.  Referring to Admiralty reports, Duncan Redford states that only thirty one per cent of all ocean convoys were attacked in March, furthermore between August 1942 and May 1943 there were eight months in which the Allies suffered higher percentage losses than March.  This indicates, rather than the ‘sudden collapse’ of the U-boat war in May, a more gradual development with successful practical application of improved Allied anti-submarine tactics and technologies.  Similar revisionist research also focuses on the absence of German optimism in this period of supposed Allied crisis, consulting statistics which clearly show an increase in non-productive U-boat patrols between January and April 1943, and stating that as early as February Dönitz had reported to Hitler that the North Atlantic run campaign was not succeeding.

This reversal in fortunes can be attributed to a number of different developments which ran parallel with the progression of training and organisation. Improvements in technology in particular played an essential role in both Allied and Axis naval operations, with both sides seeking to improve on the other’s advancements.  One example of this was the German capture in 1942 of a long range Vickers Wellington bomber fitted with Air to Surface Vessel (ASV) Mark II airborne radar, and the subsequent German invention of a listening receiver as a countermeasure to ASV.  There were also improvements made to the means of engaging U-boats i.e. weapons such as the ‘hedgehog’ mortar or the improved Air Ministry and Admiralty depth charges.  It may be argued, however, that the more influential development was that of radar and direction finder technology, aimed at locating U-boats.

An example of ‘Huff-Duff’ equipment.

By its nature, the submarine was “a weapon of position and surprise”, and so the ability to locate U-boats through the use of High Frequency Definition Finders (HF/DF) and 10cm airborne radar (ASV Mark III), both fitted in the first few months of 1943, effectively removed the element of surprise and severely hindered U-boat operations.  Burns supports this by citing Dönitz in a report to Hitler, writing in May 1943 that “the enemy, by means of location devices, makes fighting impossible”.

‘Bombes’ like these were used to simulate the action of the German Enigma rotors.

In addition to technology, any discussion of the training and organisation of anti-submarine warfare in the Battle of the Atlantic also requires acknowledgement of the work carried out by British signals intelligence at Bletchley Park in breaking the German Enigma cipher.  Post-war historians had claimed that the cryptographers at the Government Code and Cypher School (GC&CS) had shortened the war and that breaking the Enigma had been a huge success.  More recently however, Ferris has denounced the tendency for historians to over-emphasise the role of signals intelligence, stressing that while its contribution was ‘notable’, the correlation between GC&CS’ successes and the overall Allied seizure of initiative in late 1942 was complementary rather than causal.  With this in mind, although on the thirteenth of December 1942 GC&CS had broken the ‘Shark’ Enigma through the use of a four-rotor electronic ‘Bombe’, complete understanding and rapid deciphering of German signals was not fully achieved until August 1943, after the U-boats had been withdrawn.  In addition by February 1943 B-Dienst, German signals intelligence, had broken the British Naval Cypher No. 3 used for convoys, providing Dönitz with a “presen[ce] in British operations rooms”.  With both combatants therefore by 1943 possessing intelligence on the other’s routes and positions, and with direction-finding technology allowing clearer location of enemy vessels, it may be argued that signals intelligence in comparison played an important, but not crucial role in May 1943.

Training and organisation in contrast was integral to the growing successes of the escort and support groups, with several different elements combining to optimise anti-U-boat operations.  Operational Research scientists under Professor Blackett contributed to the Battle of the Atlantic by engendering a “revolution in organization”; their findings contributing to Horton’s re-organisation of the anti-submarine effort through scientific calculation and research.  From 1941 onward, Blackett and his staff applied scientific findings to naval operations, helping to devise theatre-level stratagems and also solve problems such as the optimum allocation of resources to the production of merchant shipping vis-á-vis anti-submarine escorts.  Arguably Operational Research’s most influential breakthrough, however, was the analysis of shipping losses in relation to convoy size.  This investigation, carried out during 1941 and 1942, concluded that the number of losses was independent of the size of the convoys, with larger convoys being attacked by ‘wolfpacks’ no more often than smaller ones.  It was calculated that by increasing the size of individual convoys and thereby reducing the number of convoys open to attack at any one time, there could be a reduction in losses of up to 56 per cent.  As well as achieving reduced losses, the decision taken to increase convoy size had the secondary effect of freeing up escorts for more proactive work as part of the new support groups, greatly aiding the offensive campaign.

As a result Operational Research contributed greatly to Horton’s organisational reforms of Western Approaches Command and to the way the anti-submarine campaign was conducted.  Operational Research’s findings have been dubbed “quantitative common sense”, however their collation and analysis lead to measurable successes.  The incorporation of civilian scientists so closely into high level naval command structures, reporting directly to the Vice-Chief of the Naval Staff at the Admiralty, demonstrated flexibility and innovation at the highest levels, features notably absent in the German counterpart.

The establishment of support groups marked the progression of the Allied anti-U-boat campaign from defensive to offensive actions.  The average support group comprised destroyers, sloops and frigates, which were faster and had greater range than the corvettes widely used earlier in the war.  The United States’ naval operations historian Samuel Morison recognised Horton’s reorganisation of available resources as a “tactical innovation”, highlighting the ability of the support groups to aid ‘harassed’ convoys at short notice and thus alter the outcome of many such engagements.    Availability of escort destroyers and aircraft carriers and allocation of resources to the North Atlantic had previously been a large problem, delaying the formation of support groups until March 1943 and preventing adequate defence of convoys passing through the mid-Atlantic ‘Black Gap’.  During mid to late April, in contrast, an example of the Admiralty’s Operational Intelligence Centre’s reports stated that “support groups have been invaluable this week and skilful handling has produced them in the right place at the moment when they are needed”.

Inter-service co-operation was crucial to success in the Atlantic

Airpower too was to play a vital role in convoy defence, and therefore availability was crucial.  The United States’ Navy was undergoing changes in organisation itself with regard to inter-service co-operation with the Army Air Force, but by the end of 1942 it was able to send two squadrons of very-long-range (VLR) B-24 Liberator heavy bombers to aid RAF Coastal Command.

One of the first Allied aircraft carriers used in escort groups: HMS Biter.

The development of different types of aircraft carriers had also been delayed by production problems and their allocation to the North Atlantic postponed due to the prioritisation of other operations, namely ‘Husky’ and ‘Torch’, but the first escort carriers HMS Biter and USS Bogue joined support groups between March and May 1943.  Redford emphasises the reluctance of both the US and British command to divert bombers away from the strategic bombing offensive, however the eventual allocation of air power to Coastal Command support groups especially alongside the newly arrived aircraft carriers was hugely successful.  A study carried out in the summer of 1943, centred on the successes of support groups in May 1943, found that their use in operations raised the number of U-boat ‘kills’ by 45 per cent, with most U-boats being sunk in close proximity to convoys.  In summary it may be argued that rather than as an isolated arm, the contribution of air power to anti-submarine operations was most successful when employed as part of support groups, coordinating with surface vessels.

It is clear that superior organisation of shipping and available aircraft was the key to effectively combating the U-boat threat through the co-ordination of available technology, intelligence and resources, but it was the intensive training and valuable experience of the anti-submarine escort and support groups which optimised efficiency and contributed to improved success rates.  Chalmers claimed “whatever the weapon and whatever the counter, training was the keystone of Horton’s regime”.

The Western Approaches Tactical Unit, Liverpool.

Horton ‘inherited’ the Western Approaches Tactical Unit (WATU) in November 1942 which gave synthetic training to escort captains and group commanders in the tactics of convoy battles.  In January 1943 Horton added practical ship-based training on HMS Philante, based at Larne in Northern Ireland, complete with training submarines.  Horton’s emphasis on training was also shown by his decision to increase time in harbour for individual crews for the purpose of intensive training.  By the end of the war, over 5,000 officers had completed a 6-day course in anti-U-boat tactics at WATU.  The diaries of A.F.C. Layard, although not directly applicable to the pre-May 1943 period, provide a favourable first-hand account of Horton’s training programme, Whitby commenting that “one of the great lessons of the Battle of the Atlantic was the importance of continual group training”.  This focus on training was not restricted to escort groups, with improved co-operation between the Royal Navy and RAF at Derby House allowing combined training exercises leading in turn to the adoption of the same signal codes and synchronised navigation, thus optimising the support groups’ effectiveness.  Improved defence of ships in convoy was the key to overcoming the U-boat threat.  The establishment and training of support groups therefore clearly aided the anti-submarine effort far more than any single technological invention or intelligence breakthrough.

To conclude, the organisation of convoy size and structure, the introduction of support groups and Horton’s insistence on widespread, practical training had resulted in a greatly improved and efficient convoy defence system.  By April 1943, Syrett claims, the Allies were fighting and beginning to defeat the Germans with the tools of “aircraft and electronic warfare”.  The word ‘tools’ here is significant.  It is clear that HF/DF, 10cm radar and the ‘hedgehog’, as well as the signals intelligence breakthroughs and aircraft support facilitated greater successes in the location of and engagement with U-boats.  Despite this, it is unlikely that these tools could have been used to optimum effect without the proper experience, training and synchronisation of all elements of the anti-submarine battle.  The development of the support groups represented the transformation of operations from broadly defensive to offensive, and therefore it could also be suggested that Horton’s support groups personified, so to speak, the turning point of the Battle of the Atlantic.  The training and organisation of the convoy system was the key to optimising all other advances made, and therefore was hugely important to Allied success in the Atlantic.

The author may be contacted on Twitter @zcvince


What factors account for the British army’s victory at El Alamein in October- November 1942?

This is an essay from one of our second year war studies students. Comments welcome.

The British army won the Second Battle of El Alamein rather than the Germans losing it. Although Axis forces played some role in their defeat, it was the British who determined the outcome. This essay will demonstrate that the British were able to defeat the renowned ‘Desert Fox’, Erwin Rommel by exacerbating German political and strategic issues to generate favourable conditions for a British victory. The structure aims to show that through the control of Malta the British were able to deny the Germans the necessary supplies for victory. The disparity in available resources dictated the attrition style of warfare the British leadership wanted to fight. Material superiority on its own would not decide the victor, for the British had suffered defeats at Gazala and Tobruk whilst enjoying such superiority. This suggests that something had changed, the change was in the form of a new leader, General Montgomery, and thus his impact will also be examined.

Rommel understood the correlation between available resources and the capacity to fight, consequently with limited supplies he was greatly hindered in his ability to do so. An army cannot fight if it does not have the supplies, particularly in the case of motorized warfare that relies upon fuel. According to Rommel “The battle is fought and decided by the Quartermasters before the shooting begins.”  He uses his limited fuel supplies to illustrate this, stating that “with only 300 kilometres worth of petrol per vehicle… prolonged resistance could not be expected; we would be completely prevented from taking the correct tactical decisions and would thus suffer a tremendous limitation in our freedom of action.”  One example of this was how the Germans were incapable of performing a counter-attack because “Not only could we not have kept a mobile battle going for more than a day or two, but our armour could never have returned to the south if the British had attacked there.”

In contrast, the British had been steadily building up their supplies to be “better prepared to take the offensive against the Germans.”  According to Churchill the army had a “two-to-one superiority in numbers and at least a balance of quality.”  This is supported if cross referenced with Rommel’s estimates which provide similar figures and state that these included inferior Italian tanks of which “most of them were decrepit, and barely fit for action.”  Rommel also lamented that the British had “apparently inexhaustible stocks of ammunition”  claiming that under one artillery barrage the British had fired five hundred rounds for every one of the Germans.  It is clear to see how without even taking other factors into account Britain’s material advantage severely curtailed Germany’s ability to fight.

There are several reasons for the difference in each side’s resources and perhaps the most important was the role played by Malta, a small island that is situated between southern Italy and North Africa. Despite huge effort, the Italians were unable to capture the island from the British. This provided the British with an “unsinkable aircraft carrier”  in an ideal position from which to “harry enemy ports and supply routes across both the Mediterranean and the desert.”  The British certainly seemed to take full advantage of this position, Rommel stressed that they virtually “[paralysed] our sea traffic”  citing that they were only receiving “40 per cent of our absolute minimum needs.”

Another reason for the outcome can be found by comparing the strategic cultures of the opposing forces. Stephen Bungay refers to Britain’s colonial experiences as having a major influence, suggesting that “the British Army was used to fighting small colonial wars with primitive infrastructures. As a result, its doctrine emphasized logistics.”  This is contrasted with the German system which believed it would be fighting primarily in Europe and would therefore rely on railways as its primary form of transport. The logistical capabilities of the two armies therefore developed along alternate lines, the British, prepared with a motorized logistic chain and the Germans, with inferior numbers of motorized transport and still using horse and carts.  From this it is clear to see why the Germans had difficulty in supplying their troops.

Many historians have tended not to blame Rommel for the failure, with some, such as Alan Warren arguing that he “had lost the battle but had got the very maximum out of his army.”  This may be a fair comment if we look at defensive preparations he made, which Bruce Watson claims “posed a formidable barrier”  under the conditions Rommel found himself in there is little more he could have done, to try too aggressive a strategy would have been foolish and enhanced the probability of defeat. Richard Holmes agrees, believing that “the Germans, regardless of the commander on the day, had few real tactical alternatives at Alamein.”  Rommel himself believed he could have done no more, “I’m happy in my own conscience that I’ve done all I can for victory and have not spared myself.”  He criticized those senior to him “the military career of most of the people who aimed these accusations at us was notable for a consistent absence from the front, on the principle of… “far from the battle makes old soldiers.””  This reproach further illustrates how he believed that he was not accountable for blame. John Bierman and Colin Smith agree, blaming Hitler “only if Hitler could be persuaded to take his mind off of Russia long enough to spare the Panzerarmee at least a couple of armoured divisions … could the Axis hope again for a victory.”

However, is Rommel immune from blame? One argument against him is that by attempting to seize opportunities through bold action he “pushed his logistics to their limits… They often paid off… [and] when they did not, he berated the quartermaster.”  This would suggest that Rommel believed that his job was to achieve the results and that it was somebody else’s responsibility to ensure he could do this. This notion is flawed, to blame another is to imply that you rely on them and therefore that they prescribe the strategy. This is not true of Rommel, rather he expected others to follow and make his strategies work, instead of designing more practical plans. It must be conceded that Hitler’s focus on Russia and Italian weakness created a difficult climate for him to work in. However, it does not help to follow a strategy that often stretched an army’s logistics to the limit, progressively degrading the force. This can be seen from how instead of remaining in Libya on the defensive so that he did not outpace his supply chain he “[ignored] his orders and [tried] to kick the British out of Egypt… [causing] a supply problem which in the context was insoluble.”  This reveals that Rommel had an acute misunderstanding of the political climate, a key component in the makeup of a good general and necessary for victory.

What will now be assessed is how the British contributed to the outcome of the battle. In contrast to the Germans, the British lacked a leader with the dash and daring of Rommel. Perhaps this is why he has been given such merit; despite material inferiority his ‘plucky’ style had won battles. Montgomery was a different type of General; James Holland asserts “he was certainly no innovator.”  This point is somewhat irrelevant, Montgomery’s strengths laid elsewhere, Bungay describes him as a ‘Thatcherite’ and an ‘Autocrat’ , whilst Williamson Murray adds that he was “great motivator, trainer and realist”  With the army in the condition it was prior to his entry, these qualities were what was needed. Through extensive training he reformed the Eighth Army and created a coherent doctrine. His strategy may have been conservative, but it was one that would guarantee victory.

Montgomery was familiar with desert warfare, being a battalion commander in Alexandria and had commanded a division in Palestine during the Arab revolt in the late 1930’s.  His strategy and doctrine combined the different arms of the British forces, Fred Vigman shows how the allied forces came to agree, “The Field Service Regulations June 15, 1944, [conceding] that no one arm wins battles.”   One vital aspect was “Monty’s beliefs on how air power should be used to support the army”  Rupert Smith affirms this, “[he made] the maximum use of his air force to isolate the battlefield, thus reducing the enemy forces in depth and depriving them of the opportunity to assist their own forces.”  This was used in conjunction with huge artillery bombardments that Rommel describes as “torrential” where “everything that went into it… was ground into dust”  and produced “serious signs of fatigue and a sense of inferiority among our troops.”  The huge volume of firepower laid down by the air force and the artillery supported the infantry with the World War One style ‘creeping barrage’ helped create the breakthrough necessary for victory.

Montgomery was also aided by with the luxury of being able to decipher the German’s codes with ULTRA, which was the codename given to intelligence gained from the breaking of encrypted enemy communications. Roger Spiller claims that ULTRA “To an extraordinary degree… had lifted that fog from the battlefield”  It certainly had provided Montgomery with masses of information, one German account professed that “I was staggered at the exactness of his knowledge, particularly of our deficiencies and shipping losses. He seemed to know as much about our position as I did myself”  This extensive knowledge would clearly have aided the British cause and as seen from his knowledge of the German supply ‘deficiencies’ impacted upon Montgomery’s strategic thought.

In conclusion the British victory at El Alamein can be put down to two key elements, logistics and leadership. By controlling both the sea and air surrounding North Africa the British were able to significantly weaken the Germans position and impose their will through a battle of attrition. The British were able to build up their strength in and overwhelm the enemy. They were aided by Rommel’s cavalier nature, which initially saw him win some impressive victories but in the long term weakened his army by straining his supply chain to exhaustion. Yet it was Montgomery who through vigorous training and by combining the different arms of the British forces proved to be the difference, he was the catalyst that finally demonstrated allied superiority, EL Alamein ”proved that they had learnt how to translate strategic advantage into military success on the ground.”