Hitler's 'Wonder' U-Boats

The Birth of the Cold War's Hunter Killer Submarines

Jak P Mallmann Showell

• Publisher: Frontline Books
• Year: 2018
• ISBN:
  9781526724816
• Topic: History
• Subtopic: World War II
• Index: History

Launched during the last days of the Third Reich in an attempt to restart the Battle of the Atlantic, the majority of these revolutionary Electro-U-boats never saw action. Instead they became the forebears of the Cold War’s much dreaded hunter killer submarines.The massive Type XXI was planned to replace the conventional ‘Atlantic’ U-boat that had seen service so far in the war. The Type XXIII was a smaller coastal version. The new Electo-U-boats were the first submarines to operate primarily submerged, as opposed to spending large periods of time on the surface. Hitler’s new designs utilized huge number of batteries to improve the time they could spend underwater, as much as several days, and only needed to surface to periscope depth for recharging via a schnorkel.The idea for this book came about when the author was asked to sort through files in the German U-boat Museum. Slotted in among the highly technical information were some fascinating personal logbook annotations from men who served in these boats. These non-technical, human anecdotes have been transformed to form the core of this book.Rather than compiling a technical treatise, this book makes maximum use of the personal accounts to tell the human story of how this new generation of submarines went to war under the incredibly harsh conditions that prevailed at the time. Accompanied by more than 100 images, this unique operational information is mirrored with similar reports from conventional schnorkel-fitted U-boats, which were at sea at about the same time, to provide a comparison with earlier types. It is, therefore, possible to appreciate the improvements in German U-boat design that were made in such an incredibly short period of time to place the electro-U-boat among the great technical achievements of the 20th Century.

Chapter 1

Disasters Hit Hard Germany Needs New U-boats

The Three Protagonists – the large ocean-going Type XXI, the small coastal Type XXIII and the U-boat Chief, Grand Admiral Karl Dönitz.

This drawing of a Type XXI from the Christoph Aschmoneit collection was probably drawn by Fritz Köhl, an ex-U-boatman who specialized in the reconstruction of old plans. The smaller boat displaced 275 tons submerged while the bigger one displaced 2,100 tons, making it almost eight times bigger.

A few weeks after the Normandy Invasion of D-Day, on 10 July 1944, Grand Admiral Karl Dönitz (U-boat Chief and Supreme Commander-in-Chief of the Navy) sent out 273 copies of a letter that stated:

The new Type XXI possesses exceptionally strong underwater fighting capabilities … This new type will be capable of offsetting the lead attained by enemy anti-submarine defences … With this boat and with other new types already in production it will be possible to begin a new and successful U-boat war.

While the first of these new boats had been launched only a few weeks before Dönitz wrote that letter, the story of the Type XXI goes back much further, to the dark beginnings of the First World War when soldiers at the front had the audacity to tell the German High Command that they needed different U-boats to those that were already in production. The major snag was that industry was working to capacity and could not cope with additional demands. So, instead of turning to new technology to increase production the shipyards recruited untrained labour, made use of the simplest machinery and laid the boats down on makeshift slipways. At the same time, the specifications for the new designs stated that the boats had to be simple. They were going to be manned by men who did not have the right qualifications, hadn’t been to sea before and, on top of that, there wouldn’t be enough time to train them properly. Although this may sound absurd, this incredible combination reaped utter havoc that not only terrified the hysterical public but also worried sedate world leaders.

The smaller Type XXIII.

1. Periscope

2. Radar detecting aerial

3. Schnorkel with head valve

4. Pressurized container for life rafts

5. Hydroplanes

6. Torpedo tube door

7. Position for ‘periscopic’ radio aerial

8. Mooring bollards

9. Balcony apparatus with underwater sound detectors

10. Vents

11. Rudder

12. Jumping wire. This served as radio aerial and as anchor for safety harnesses when men worked on the upper (outside) deck

A quarter of a century later Germany used the same combination to launch what was then the biggest submarine fleet and once again used this simple formula to bring the Allies to the brink of defeat. Therefore, it is no wonder that the German Navy modified this trick once again in 1943 to build what was then the ultimate in submarine technology.

The big problem for Germany was that the know-how that had been generated during the First World War evaporated rapidly again during the following years when the country was not allowed to build or own submarines. The period between the end of the First World War and March 1935, when Hitler’s first U-boats were launched, was long enough for much of this submarine expertise to have been lost for good. Germany did keep abreast with new technological developments, but this highly secret activity involved only a tiny handful of engineers and they did not do much more than focus on refining individual components to make machinery more effective so that the team could plan new submarine types for the future.

From 1935 onwards Hitler’s new submarine development was hampered by two significant factors. First, those who dabbled in submarines were located in seaports and the staff who determined what to build were stationed a long way away in Berlin, without any significant connection between the two. Second, much of the early secret planning for the new fleet was nullified by the Anglo–German Naval Treaty of that year, which allowed Germany to build a submarine fleet up to a strength of about one third of the British Navy. This tonnage restriction made it necessary to scrap earlier plans for specialized submarines and concentrate on more general-purpose craft. So specialization had to be rejected in favour of generalization, where a few basic types would have to cope with all demands.

A corner in the German U-boat Museum commemorating Grand Admiral Karl Dönitz with a plaster cast made after the war by Heinrich Andreas Schroeteler, who had served as commander of U1023. Low-ranking sailors often said of Dönitz: ‘The BdU (Commanderin-Chief for U-boats) always has a fitting word for everybody.’

To understand what was going on in Germany during this turbulent time it is necessary to dispel some common misconceptions. It is often said that the Second World War U-boat Chief, Karl Dönitz, had been an avid submariner during the First World War, which is rather misleading. He actually moved into submarines as late as 1917 because there was no alternative. After the war he had the ambition to become a cruiser squadron commander. So, it can be said that he had some submarine experience, but he never had any longing to go to sea in these stinking coffins. What’s more, he had absolutely nothing at all to do with U-boat planning, design or construction until after the beginning of the Second World War. His isolation, first as flotilla leader and later as flag officer for U-boats, can easily be illustrated by the fact that he was not even given command of the newly formed U-boat School boats. These came under the jurisdiction of the Torpedo Inspectorate.

Another common misconception is that the U-boat offensive collapsed in May 1943. This cannot be true because the turning point must have come when individual U-boats stopped sinking ships and that happened towards the end of 1940, when unusually harsh winter weather brought the U-boats’ so-called ‘Happy Time’ to an end. The first major sinking of U-boat aces that occurred a few months later, in March 1941, probably marks one of the most significant events of the U-boat war.

During the autumn of 1940 each U-boat at sea was sinking up to six ships every month. This figure dropped so rapidly throughout 1941 that there were five months when each U-boat at sea was sinking fewer than one ship. These depressing figures recovered slightly when the United States joined in the war and allowed U-boats free-range hunting along its coast without providing merchant ships with any serious protection.

Despite the incredible carnage in American waters, U-boats had incredibly long voyages to reach their operations areas. In other words, there were many U-boats at sea doing nothing more than sailing across the Atlantic. As a result the sinking rate reached two ships sunk per U-boat for only one month of 1942 and for the rest of the time it was so low that almost two U-boats were required to be at sea for a complete month to sink one ship. So, throughout 1941 and 1942 there were a large number of U-boats at sea but the majority were sinking nothing at all. The intelligence blackout in England, with Bletchley Park unable to read the U-boat code for much of 1942 because Germany changed to a new four-wheel code machine in February, meant that those who were responsible for keeping U-boats away from convoys had already won a significant victory.

In 1942, the number of U-boats at sea increased most dramatically; from January onwards there were more than sixty every day. This figure climbed to eighty-five during the following month and then reached more than 100 in May. Yet, throughout all those bitter months of huge wolf packs marauding the seas, there never was a large-scale convoy battle. That did not occur until March 1943.

The U-boats’ poor performance was made worse by numerous determined attacks against them. Getting close to convoys had already become a major issue in 1941 when commanders noted that aircraft were becoming more than a mere nuisance; they were becoming deadly, making it obvious that the old methods of attack were no longer working. Admiral Karl Dönitz, the U-boat chief, was fully aware of these detrimental results and the U-boat Command struggled hard to gain the upper hand, but none of the new techniques that were introduced produced any significant results.

It was the summer of 1942, long after Russia and the United States had joined in the war, when the U-boats’ poor performance came to such a depressing climax that Dönitz travelled from his headquarters in Paris to Berlin to discuss the situation with the highest naval leaders. This meeting on 28 September 1942 resulted in Grand Admiral Erich Raeder requesting a meeting with the Führer as soon as possible. It would seem that Hitler already had enough inkling of what was going on at sea that he convened that meeting during the afternoon of that same day. The outcome of this two-hour long presentation by the U-boat chief, supported by seven naval experts, was that Hitler agreed with the major suggestions that were proposed.

The most important request by Dönitz was to speed up the introduction of the new high-speed submarine that had been designed by Hellmuth Walter. Following that he asked for the development of new torpedoes that were already undergoing trials to be given higher priority. Dönitz pointed out that the opposition was not sinking a large number of U-boats because radar detectors that were being installed in increasing numbers made it possible to evade attack, but the opposition’s radar was preventing U-boats from closing in on convoys at night. Dönitz remarked that since the beginning of the war there appeared to have been no change in Asdic, the device that detected submerged submarines, and U-boats with high underwater speeds should produce significantly better results by passing under the protective radar screens to reach their attacking positions.

The next step in the production of the new high-speed submarine, after Hitler had given his approval, was for construction experts to assess the progress made with the experimental projects that had been ongoing since before the beginning of the war. The U-boat Command and the main bases in France were a long way from the secret trial areas and some travelling into out-of-the-way research stations was necessary to find out exactly what progress had been made. As a result, it was November 1942 before a team...