The U-Boat War

Lawrence Paterson

A new history of U-Boat warfare tells us German subs away from the traditional view
Sinking of the Linda Blanche out of Liverpool by SM U-21, by Willy Stöwer
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A strong mythology surrounds Karl Dönitz’s U-boat War War; not least of all the idea that roving U-boat ‘Wolfpacks’ routinely savaged North Atlantic convoys and posed a dramatic threat to Great Britain’s continued survival after the disastrous battle for France in 1940. Dönitz’s pre-war tactical doctrine had focussed on the ‘Rudeltaktik’ (‘Group Tactics’ anglicised as the ‘Wolfpack’), an idea originating with the commander of the First World War’s U-boats, Fregattenkapitän Hermann Bauer. Bauer had achieved great success in 1917 with Germany’s unrestricted U-boat offensive, bringing Britain’s merchant shipping balance to near bankruptcy. However, this was achieved by U-boats operating independent of each other or any centralised control and as such they were defeated by the British Admiralty introducing convoying of merchants as a means of ‘collective defence’.

Sensing that the impetus was slipping from his grasp, Bauer proposed to German Naval Staff that U-boats alter tactics and instead be coordinated and controlled by means of a large radio-equipped transport U-boat that could operate as a mobile command centre. Staffed by trained wireless and decryption personnel, this U-boat would monitor British radio signals to anticipate convoy movements and direct accompanying combat boats to intercept en-masse; the theoretical birth of the ‘Wolfpack’. However, despite Bauer’s sound logic, the proposal was rejected.

Subsequent defeat of Germany’s U-boats was mistaken in Britain as decisive Allied victory, though just under half of operational U-boats built remained combat-effective by the time of the November 1918 Armistice. It had not only been improved anti-submarine warfare techniques and the introduction of escorted convoys that had beaten the U-boats but also their failure to forge fresh tactical doctrine, particularly after Bauer’s replacement in June 1917.

By September 1939 as Europe plunged once again into war Dönitz had drilled his commanders and crews extensively in improved combat methods. Gone were long-distance submerged torpedo attacks, the men instead trained to launch torpedoes at close range while running surfaced at night, using the U-boat’s high diesel engine speed, manoeuvrability, and low profile to its fullest advantage. Radar was uncommon on enemy ships at that time — as well as its potential underestimated in Germany — and by operating surfaced, British ASDIC sonar location was rendered useless.

A Kriegsmarine U-boat, by Augusto Ferrer-Dalmau.

It is important to realise that the Second World War’s U-boats were more ‘submersible’ than true ‘submarine’. While surfaced they were powered by twin diesel engines to a maximum speed of just over 17 knots; outpacing many early convoy escorts. Submerged they were limited to a maximum of around 7 knots, decreasing as the batteries discharged, only able to be replenished by use of diesels while surfaced. Though structurally capable of an impressive submerged depth — underestimated by the Royal Navy who altered their depth charge settings after the capture of U570 in August 1941 — they remained slow and relatively unwieldy, the limited battery capacity eventually forcing the boat to surface lest the propellors cease to turn and the U-boat sink one final time.

The reality behind the mythologisation of the Second World War’s U-boat offensive is that it never really came close to achieving its aim of starving Great Britain into submission by attacking the primary North Atlantic convoy routes. The most successful U-boat operations were actually mounted away from this theatre of action, instead taking place in the Caribbean Sea, off the West African coast near Freetown and into the Indian Ocean as an extension of the attack on South Africa. These operational voyages were both daring in their scope and execution and extremely arduous for the men aboard U-boats that, by the middle war period were slipping rapidly into obsolescence.

So, what of the men that crewed these U-boats? They too have been the subject of much misplaced information, perhaps the most prevalent being that it was an elite service crewed by volunteers. Though many original members of the pre-war U-boat service were indeed volunteers, and Dönitz took great pains to instil a sense of belonging to an exclusive breed of fighting men, this remains patently untrue of the U-boat service as a whole. In the same way that Rommel’s famous Afrika Korps is often represented as an elite Wehrmacht unit, U-boat men were no more an elite branch of service than, for example, service aboard the Schnellboote (fast motor torpedo boats). Men were routinely posted to U-boats after basic training dependent purely on manpower requirements. There have been scholarly attempts to interpret patterns in the type of men transferred to U-boat service based on their civilian careers, residencies and so on, and I believe they have proved no more illuminating than if similar studies had been made regarding other branches of Kriegsmarine service, or indeed elements of the Luftwaffe (air-force) or Heer (army).

U-boat crews were also reputed to be fanatical, not least of all due to their willingness to mount combat missions through to the last days of war when casualty rates were extremely high. However, this too, has been largely misrepresented. As a service branch they were probably the least politically motivated than other parts of the Wehrmacht. Casualty rates were indeed heavy — approximately three quarters of U-boat men were killed in action — though their resilience in combat was mirrored throughout the German armed forces which continued to fight until the last days of war. Similarly, on the other side of the hill, casualty rates were extremely high within RAF Bomber Command and the USAAF’s Eight Air Force for example, yet they never faltered in their undertaking of dangerous missions deep into enemy airspace.

Nevertheless, Dönitz ensured that his men received the best possible treatment while ashore and went to great lengths to try to personally debrief his officers and meet returning crewmen when at all possible. He endeared himself greatly to his men, who named him ‘The Lion’ (Der Löwe). Jürgen Oesten was the commander of three wartime U-boats and served from the first days of combat to the last.

“I think it was in 1938 that we had some sort of wargame, trying to establish how any submarines would be necessary to cut the supply line to Britain that stretched across the Atlantic… The conclusion was that at the beginning of the war we needed 300….we had nearly 60 U-boats; only 40 of them combat vessels and 30 of them too small for such a vast ocean…We were not prepared for this sort of fight, but Hitler was too stupid. He thought he could play around in Europe without Britain’s interference. Dönitz was a good naval officer and because of that his U-boat war was carried right through to the bitter end. His handicap was that he could be influenced by emotions and Hitler was able to let him swim in a soup of emotions, disregarding the actual facts. I think, looking back, we managed to cut about 1 percent of the supplies to Britain.”

Nevertheless, the period between July 1940 and March 1941 is famously remembered as when the Wolfpacks truly began to bite and has often been referred to as the ‘Happy Time’ for U-boat crews. But at least one of the veterans involved recalled this entire period in a completely different light. Otto Kretschmer, the highest ‘scoring’ U-boat Ace of the Second World War remembered:

“The ‘Happy Time.’ I don’t like this term. We were the first ones to probe the defences of the enemy and this was not a happy time. Because 50% of our forces perished. I remember when I was with U99 and went into the Atlantic for the first time, I found out that before me there were six submarines sent to the Atlantic and three were sunk. Fifty percent losses. So, this is called the ‘Happy Time’? I don’t know why. And, of course, we had been trained during peace time and we had to discover whether the peace time tactics were any good for war, which they were not at all times…The ‘Happy Time’ had been invented by Propaganda Kompanie in Germany; they were the first to speak about it.”

Kretschmer was captured after U99 was sunk in March 1941.

U-boats did indeed fight to the bitter end, though after 1942 they were outmoded and in perpetual decline as Allied technological advances rapidly outstripped German. Industry and development within the Third Reich was bedevilled with problems, not least of all the constant competition between services for whatever resources were available. This kind of internal conflict became a hallmark of Hitler’s style of control; no unified goals leading to no unified hierarchical structure either governmentally or militarily. Naval requests for investment of the kind of focussed time, money and scientific application that would have been necessary to revolutionise U-boat design was lacking throughout the war, despite the best efforts of many officers and bureaucrats from within the industrial sector.

Nevertheless, though as previously stated, the U-boat service was far from an all-voluntary force, there remained men eager to join Dönitz’s band of brothers’. Ludwig Stöll was one of these late war volunteers for U-boat service.

“I had been fascinated by U-boats since the last war and as soon as I was old enough, I enlisted immediately in the Kriegsmarine, determined to become a U-boat Engineering Officer. There was, of course, the weeks of infantry training before we actually became officer candidates and began training in the use of the U-boat. Finally, I was aboard one! I was transferred to U148 to train in the Baltic. This was a little Type IID and although I had no political leanings at all — I had even managed to avoid service in the Hitler Youth! — I was ready to go to combat at sea…to sail against England! Of course, it never happened. The boat was eventually laid up and scuttled. In the meantime…I was back wearing a helmet and field gey and marching into action. We had been transferred to the 2nd Naval Infantry Division.”

Ludwig Stöll went into combat armed with a Panzerfaust and rifle against British Armoured units near Bremen. Though the naval infantry acquitted themselves surprisingly well, they stood no real chance of success, and he was captured. However, his fascination with the U-boats of the First and early Second World War remained physically manifested in books about Germany’s U-boat heroes that he had collected since childhood. Stored beneath the floorboards of his mother’s home in Berlin, they survived the arrival of the Red Army and destruction of the city, and, after Ludwig sadly passed away from cancer were generously left to me to help tell his and his comrades’ stories. I hope that I have done their memories justice.

Lawrence Paterson is the author of a number of titles on the Kriegsmarine. The U-Boat War: A Global History 1939–45, published by Osprey, is his latest.