81: All About Them Boats


Because you know I’m all about them boats, about them boats, no aircraft.


  • War and Economy in the Third Reich by R.J. Overy
  • The Wehrmacht and German Rearmament by Wilhelm Deist
  • The Third Reich and Yugoslavia: An Economcy of Fear, 1933-1941 by Perica Hadzi-Jovancic
  • Hitler A Biography by Ian Kershaw
  • Hitler’s Eagles by Chris McNab
  • Quest for Decisive Victory: From Stalemate to Blitzkrieg in Europe, 1899-1940 by Robert M. Citino
  • The Blitzkrieg Myth by John Mosier
  • The Path to Blitzkrieg: Doctrine and Training in the German Army, 1920-1939 by Robert M. Citino
  • 1930s German Doctrine: A Manifestation of Operational Art by Tal Tovy
  • The Blitzkrieg Myth: How Hitler and the Allies Misread the Strategic Realities of World War II by John Mosier
  • The Origin of the Term “Blitzkrieg”: Another View by William J. Fanning Jr.
  • Storm of Steel: The Development of Armor Doctrine in Germany and the Soviet Unition 1919-1939 by Mary R. Habeck
  • Hitler’s Eagles by Chris McNab
  • Military Innovation in the Interwar Period Edited by Williamson Murray and Allan R. Millett
  • Ship-of-the-Line or Atlantic Raider? Battleship Bismarck Between Design Limitations and Naval Strategy by Timothy P. Mulligan
  • Strategy for Defeat the Luftwaffe 1933-1945 by Williamson Murray
  • Battleship Bismarck: A Design and Operational History by William H. Garzke Jr., Robert O. Dulin Jr., and William Jurens
  • The Wages of Destruction: The Making and Breaking of the Nazi Economy by Adam Tooze


Hello everyone and welcome to History of the Second World War Episode 81 - Germany Prepares for War Pt. 4 - Alles über sie Boote. This week a big thank you goes out to Josiah, Kelly, and a person with the screen name Pirate for choosing to support the podcast on Patreon. They get access to ad free versions of all of the podcast’s episodes plus special member only episodes roughly once a month. Head on over to historyofthesecondworldwar.com/members to find out more. One of the interesting outcomes of having done the History of the Great War podcast before this one is that it has given me a chance to do research on the events before the First World War and then before the Second. There are many things that are very different between those two time periods, but there are also some points that allow for really interesting comparison. In my mind, one of these is the comparison of the plans and preparations of the French Army before the two World Wars, where the experience of the First World War, and the French mindset before 1914 caused a complete change and a move in the opposite direction before 1940. We discussed that shift back in Episode 61. Another interesting topic on this line of discussion is around the build up of the German Navy. Before the First World War the German Navy would be massively expanded due to the complete shift in Naval strategic planning put in place by Admiral Tirpitz, and the German Navy would transform itself from a small force to the second most powerful navy in the world by 1914. Before the Second World War the German Navy would once again find itself starting with very little, due to the complete destruction of the German Navy by the Versailles treaty, but from these humble beginnings they would eventually grow to be a strong force by the start of the war. In both cases this expansion was driven by one desire and one unavoidable problem. The desire was for the German nation to have some ability to project power onto the seas, starting with the ability to safeguard the Baltic and North Seas, and then latter expand that reach beyond those coastal seas. This desire put them at odds with continental naval powers, most importantly the French. The unavoidable problem was that as Germany expanded its naval power, it always ran the risk of being confronted by the Royal Navy, and this made a German naval build up a bit tricky. Before both world wars German naval planners would have to contend with the fact that they would be starting from a great disadvantage, at least relative to the Royal Navy. This is where the two generations of German naval leaders chose different paths. Before the First World War the plan for the Imperial German Navy was to become large and powerful enough to meet the British fleet at sea and at the very least be able to do significant damage. This meant building as many battleships as possible, of similar type to what the British were building, along with battlecruisers, also to make British construction. Before the Second World War the goals would be different, but an emphasis on capital ships, particularly battleships would remain. This episode will be at least partially around why this decision was made. We will track the creation and build up of the German Navy over the course of the 1930s, both its surface vessels and its U-Boats. Then we will end with the naval expansion plans that were just beginning to be put in place before the start of the war. Along the way we will discuss several reasons why design decisions were made at the time they were made, and then how the roll of the German Fleet would change over time. The end goal will be to answer the general question of why the German fleet was what it was in 1939 when the war started. A small note on terminology throughout this episode: After the First World War the Imperial German Navy was renamed as the Reichsmarine, which was then renamed in 1935 to be the Kriegsmarine. You will hear both of those names throughout the episode as we circle around that time period quite frequently.

If you wan to talk about the build up of the Reichsmarine, Kriegsmarine, whatever it was called, you have to start with the man at the top: Grand Admiral Erich Raeder. As with many Generals, Admirals, and other top officers in the 1930s, Raeder had been an officer during the First World War. He had been the Chief Staff Officer for Admiral Franz von Hipper aboard the battlecruiser Seydlitz at the battles of Dogger Bank and Jutland. After the war he would continue to be promoted among the much reduced ranks of naval officers during the 1920s, eventually being put in charge of the Reichsmarine, such as it was, in October 1928. During the 1920s and early 1930s there was a disconnect within the Reichsmarine between what the war they were planning to fight, and what they could actually do. The Reichsmarine had very little real power during the 1920s, its most powerful ships were pre-dreadnoughts that would have been obsolete even in 1914. But from the perspective of what the Reichsmarine was planning to do in a war there was a very different picture, as they planned to launch offensive operations into the Atlantic to attack enemy shipping and trade. This would allow it to make quick and meaningful contributions on the high seas. This plan was based not on the realities of the time, but instead the hopes for the future, with the general theory being that at some point in the future Germany would throw off the shackles of Versailles and begin to rebuild it armed forces. This was a very similar mindset to what was at the same time present in the Reichswehr, or the German Army, during this period. They were both always planning for the future, which made their plans at time seem fanciful at best and delusional at worst. The entire German military would get its period of expansion though, and that period would begin not long after Hitler took power. For the Reichsmarine they would result in the Replacement Shipbuilding Program which was launched in March 1934. This plan, like almost all naval expansion plans of this era, had an extremely long horizon. It was scheduled to take place over 15 years, not completing until 1949, and at that date the Reichsmarine would have a force of 8 battleships, 3 aircraft carriers, 18 cruisers, 48 destroyers, and 72 submarines. The length of the plan, all 15 years of it, was necessary due to the state of German shipbuilding at the time, and just how long many of the ships would take to build in the years before full rearmament. Then in June 1935 the Anglo-German Naval Agreement would be signed, which allowed the German Navy to build up to 35% of the Royal Navy in terms of displacement. This seems like a lopsided treaty, around 1/3 as many ships could be built, but it was very important to both sides for a variety of reasons. For the British, it has the effect of bringing the German’s into the naval treaty system, in a kind of third hand way, and also ensured that they were building the same type of ships that the Royal Navy was also building. It also required information sharing about what the Germans were building. This was important because in a like for like conflict, the Royal Navy had a level of supremacy in the mid 1930s that was unassailable, as long as they knew what the enemy was doing and knew the ships that they were building matched up to what the British were planning to fight. From the German side the 35% number did not actually matter at all, they knew it would be years before they could even approach that level of total tonnage, as it takes a long time to build ships. The general assumption among German leaders was that by the time that the 35% limit became a problem, they would be in a position to just leave the treaty behind, which is exactly what they would end up doing. The most important feature of the treaty for Germany was that it was the first international recognition that Germany should even have a Navy that contained new and large ships, as the Versailles treaty had placed strict limitations on what the Germans could build. It would be one of many cracks in the wall of the Versailles limitations that would appear in the years before 1936.

When considering building new ships, the question would always start at what should be built. This question would occupy countless man hours in the navies around the world during the interwar period, and for Germans it would be not different. So many different factors went into the decisions around ship design, but we can start with a relatively straightforward one, who was the Reichsmarine planning to fight. When the Reichsmarine had been created after the First World War it was recognized that it had fallen very low, and that Poland would be an appropriately powerful naval adversary. Then as rebuilding began in the 1930s there would be certain assumptions made about who Germany was likely to fight in a future war, most importantly there had to be a decision made about the most powerful European Navy, the Royal Navy. Within the European naval sphere the Royal Navy had to be considered in any naval planning, or it had to be ignored. Within the Reichsmarine this was accomplished by simply basing all naval planning on the assumption that in a conflict on the continent Britain would remain neutral. This was kind of required for any German naval planning to make sense, because no matter what was planned for, the relative power and presence of the Royal Navy threw off any possible equation, especially around surface ships and their employment. Because the Germans wanted to build surface ship, the only way that it could be done was by ignoring the impossible problem, which is certainly a choice for what you can do with problems, although I don’t recommend it. This assumption would continue until after 1937, which makes a lot of German naval plans between 1933 and 1937 seem hopefully optimistic if you assume they will be facing the Royal Navy, but if you make the same assumption that Britain will remain neutral, things start to make a bit more sense. But if they did not see the Royal Navy as a primary threat, who were they targeting? Well, as would so often happen in the early 20th century German military planning, they were planning to face the French. The French Navy, or Marine Nationale, was nothing to scoff at during the interwar years. It had joined in Washington Navy Treaty as one of the second level powers, given the same displacement limits as the Italians, the primary naval rival of the French at the time. This meant that if the French built up to their limit they would still only be a 1/3 the size of the Royal Navy, making them a far more reasonable target for German naval planning. This focus on France is important for our episode today, because as we discuss the types of ships being designed and built during this period and how they were planned to be used, their expected enemy was generally France, and their combined power was calibrated against the French Fleet as an adversary. In such a conflict the general plan was to use a combination of surface vessels and U-Boats to launch a commerce raiding campaign against French shipping in the Atlantic. This is one of the reasons it is important to think about the Germans planning against the French, because the French had a lot fewer ships than the British, but the size of the ocean remained constant, which gave surface raiding a far greater chance of succeeding simply due to the dissipation of enemy resources. Such a raiding scheme seems relatively straightforward, but it required a complete reworking of German naval designs when compared with what had been done before the First World War. During that period of construction the assumption was made that the German ships would be primarily fighting British ships in the North Sea, which meant that they could deprioritize endurance at sea, because they just would not be required to sail far from German bases. The situation in the 1930s was the opposite, with the plan calling for long range commerce raiding, but without the assistance of any overseas bases from which resupply could happen, this put a lot of emphasis on ship endurance. This meant designs had to change in some very obvious ways, the ships needed more fuel, food, drinking water, and ammunition, but it also required less obvious considerations, for example there needed to be a greater ability to do repairs at sea and they had to be able to stand up to the beating that they would take in the North Atlantic. With these changes they also had to be able to fight the ships of other navies, and for this the construction office of the Navy would do its best to learn about foreign plans and developments, and to incorporate any innovations that might given German designs an advantage.

The first major new design by the Reichsmarine would result in the Deutschland class of cruisers, which the Germans would call Panzerschiffe, or armored ship. These ships would be designed and approved before Raeder took his position at the head of the German Navy and they were at least theoretically designed to fit within the 10,000 ton limit placed on German ships at the time. The basic idea was that they would be well armed enough to deal with any cruiser that might attack them, but they would be fast enough to run away from any larger ships. The cruisers that the Panzerschiffe would be facing were limited by the provisions of the Washington Naval Treaty to a size of 10,000 tons of standard displacement and with a maximum gun size of 8 inches, or 203mm. Because this was the largest that a cruiser could be, of course every major navy in the world built right up to and past the limit. The resulting building race around what were soon referred to as “Treaty Cruisers” would take place throughout the interwar period as each navy tried to take 8 inch guns and place them within 10,000 tons of displacement. Every navy attacked that problem differently, but in each case sacrifices had to be made, which resulted in a lot of designs that sacrificed almost all armor in the name of speed and guns. I will not go through a full review of treaty cruisers during this episode but I do think that the designs and their evolution is really interesting. The original limit was not based on any kind of agreement between the navies that 10,000 tons and 8 inch guns was some kind of correct formula for cruisers, but instead just based off of what the latest cruisers of the British Navy, the Hawkins-class, were at the time of the Washington Naval Conference. The navies of the world started building, or were planning to build, so many of the treaty cruisers that they would become a major topic of conversation at the London Naval Conference in 1930. At that conference treaty cruisers would have the same total displacement limits placed on them that the capital ships had been given at Washington in 1921. These were the ships that the Panzerschiffe were designed to face, because they would mount 6 11 inch, or 283mm, guns. This would theoretically give the Panzerschiffe more firepower than the cruisers. They would then also have a top speed of 26 knots, which would be sufficient to run away from the battleships that might show up to support the cruisers. The two classes of ships should not really be compared in too much detail, but I do find it humorous that the idea of having larger guns than smaller ships and faster than larger ships was the initial design direction of battlecruisers when they were introduced in 1906. But there were massive differences between how the Panzerschiffe and Battlecruisers accomplished this goal. The battlecruisers basically took the basic battleship design and reduced armor and increased power to achieve higher speed, while the Panzerschiffe started at something much closer to a cruiser and placed larger guns on it. To achieve the power necessary for this, and also to provide the endurance that the Germans felt was so essential to their commerce raiding mission, the Panzerschiffe would be powered by diesel engines. The usage of diesel engines is a real differentiator for this class of ships, and was not really matched by any other ships at the time, which were all using steam turbines that were powered by burning fuel oil. The biggest advantage for the diesel engines is that they provided greater endurance, because they more efficiently used fuel, but at the cost of being more expensive, more complicated, and heavier. With 11 inch guns and diesel engines there would have to be a point of sacrifice, and it would come in the form of the armor provided to the ship. This would later be problematic, but as mentioned was not much different in trade off to the treaty cruisers it was designed to meet at sea. The first Panzerschiffe would be laid down on February 5, 1929, and it would take two years before it was completed. Eventually three of these ships would be built, all during the early 1930s, by which point the developments in the French and other navies would require a reconsideration of the design.

When the Deuschtland class was introduced it was seen as a major threat by both the Royal Navy and the French Navy. In retrospect this fear probably was not completely warranted, and during the war the Panzerschiffe would not prove to be the terror that they seemed in the early 1930s, but concerns about the ships would cause the French to introduce a new class of warships, the Dunkerque class battleships. The class was built to directly counter the threat posed by the Panzershiffe, and to do so they would mount 8 13 inch, or 330mm guns within a 26,500 ton displacement. While the guns were problematic, the far more concerning feature of these new French battleships was their top speed, 29 knots. The Panzershiffe only had a top speed of 26 knots, which meant that their key ability, to run away from any ships that were larger, was already under serious threat when the first Dunkerque class ship, the Dunkerque, was laid down in 1932. The problems posed by the Dunkerque’s meant that the fourth Panzerschiffe was actually cancelled to allow for a more all encompassing reconsideration of the design. During the 1930s every major battleship built around the world would also be faster than the Panzerschiffe, which had the effective of invalidating the entire concept of the class of ships before they even had a chance to prove themselves. The shift in speed was an evolution of capital ship design that it easy to forget, with the speed of battleships increasing from the low 20 knots during and after the First World War, and then shifting to the high 20s and even 30 knots by the time that construction on capital ships resumed in the last years of the 1930s. This was disastrous for a ship like the Deuschtland class, whose entire concept was around how its speed matched up with other ships.

With the cancellation of the fourth Deustchland class ship, planning turned to what would be its successors. The initial conversations revolved around increasing the size to 19,000 tons, but with the same number and size of guns, this would have provided for more speed and armor. Raeder pushed for the addition of another triple turret, bringing the number of guns from 6 to 9, but that would have pushed the displacement to 26,500 tons. Raeder’s design also included a more important change, which was to bring the gun size up to 330mm, or 13 inches, to match the French. Eventually the design was scaled back down to 11 inch guns, although there would be 9 of them in the final design. This class would also revert back to the more traditional use of steam turbines, due to problems with scaling up the diesel engines of the Deustchland class. If diesels were to be used to power ships that would eventually be 2.5 times the displacement, the engines would have to produce much more horsepower, and there were concerns both that this could be done and that it could be done within the budget and dimensional constraints of the new ships. The two ships of the class would be ordered in January 1934, laid down in mid-1935, and then completed in May 1938 and January 1939. The lengthy period of construction for what would become the Scharnhorst class, and that was lengthy even by pre-rearmament standards, was mostly due to the fact that they were the first ships of their size that German shipyards had been asked to build since before the First World War. Warships of such a size required all kinds of special tooling and construction equipment, but they would prove to be incredibly valuable when it came to making it possible to Germany to build even larger ships in the years that followed. While the Scharnhorst class was clearly classed with battleships, at roughly the same time there would be a new class of German heavy cruisers which would also be built. These were the Hipper-class of heavy cruisers that were ordered in October 1934. The Germans would claim that the Hipper class met the Washington treaty limits of 10,000 tons, but they were not even close, with a total displacement of 16,000. They would also be armed with 8 inch guns, and were powered by steam turbines. Eventually 3 of the Hipper class would be finished and put into service, although there were two additional ships that were under construction and were reasonably close to completion when they were cancelled.