During the late 1930s the expansion of the Kriegsmarine would get serious.
Hello everyone and welcome to History of the Second World War Episode 82 - Germany Prepares for War Part 5 - Boats Part 2. This week I would like to remind everyone that one of the quickest and easiest ways that you can support the podcast is by dropping a positive review for the podcast on your podcast listening service of your choice, or by simply recommending it to your internet and real world social circle. Believe it or not old fashioned word of mouth is still an important way people find out about things. Last episode we discussed the course of the German Navy during the 1920s and early 1930s, culminating with the design of the Scharnhorst class battleships and Hipper class heavy cruisers. These two ships represent a good place to start this episode as well, because they were an important turning point for the German Navy. I feel like the temptation with ship classes during the 1930s is immediately start diving into numbers. Gun calibre, speed, armor thickness, armor placement, armor angles, anti-aircraft guns, etc. etc. With the Scharnhorst and Hipper class we could dive into those numbers, and they are in many cases meaningful choices around what the Germans believed was the best ship designs based on their construction capabilities and available materials. I could also start comparing the ships to those being built by other navies at the time, but I think at the moment I will avoid those detailed number based discussions. Instead I think a great place to start is a discussion of what the ships represented for the Kriegmarine. They were the first major classes of ships built after Hitler came to power and as part of much larger construction problems that were no longer handicapped by the stringent requirements of the Versailles treaty, and they also made one thing very clear. Regardless of how the Germans planned to use their naval surface fleet, they had very decisively reverted back to what was clearly the naval orthodoxy of the mid 1930s. They were building steam turbine powered battleships and heavy cruisers that looked a lot like what everybody else was building at the same time around the world. There were certainly differences, and some of those differences were impactful because every navy had its own set of limitations and differing opinions on how the various facets of designs should be weighted in the design process, but they were clearly of the same time. I think this is interesting and important because in the early 1930s Germany did have a chance, due to the fact that its navy essentially did not exist to ry something different. The Deutschland class for really different than what other navies were building at this time, they were incredibly flawed, but they were different. Some of those differences can and probably should be heavily criticized in retrospect, but at the time they caused serious consternation among Germany’s possible enemies all over Europe. With the Scharnhorst and Hipper classes, the Kriegsmarine reverted back to building along the same lines as everybody else. There was a whole host of reasons for the decision to pursue such a path. Everything from the personal views of Raeder and Hitler to the treaty agreements with Britain to the simple societal idea of what a Navy was, and a whole bunch of other reasons. Nowhere was that more clear than in the largest ships built for the Kriegsmarine in time for the Second World War, the Bismarck class battleships. We will then talk about the other very iconic tool used by the German Navy, the U-boats before we finish up by discussing Germany’s massive naval plans formulated in the last years before the war, Plan Z which would have represented another massive expansion of German Naval power, none of which ended up actually happening.
The origins of the Bismarck class of battleships, beyond just the German design to build larger more powerful ships, lay in the beginning of new battleship construction which would take place first in Italy and France and then in other nations in the late 1930s. This was allowed by the Washington and London Naval treaties because after so many years many of the older battleships present in various navies were reaching the age at which point they could be replaced. This first round of construction would result in the Richelieu class for the French and the Littorio class for the Italians. These ships represented some of the first new designs to begin construction since the treaties had been signed, and the Germans felt that they needed to respond to their large size and power. They would both mount 15 inch guns and would be claimed to fit within the 35,000 ton displacement limit of the treaty system, but would would come in thousands of tons higher than the limit. The Bismarck was designed to match up with these ships, kind of in the same way that the French had designed the Richelieu’s in direct response to the Littorios. In the same way that the Scharnhorst class started with the Deuschtland class, but as a scaled up version, the Bismarck began life as a scaled up Scharnhorst. The first thing to increase was the size of the guns, up to 14 inches from the 11 inch guns on the Scharnhorst, but then this required other redesigns which quickly spooled out into what was eventually an entirely new ship. The biggest problem is that they wanted to keep the speed quite high, with the original plan being to have a ship that could make 33 knots, but they could not do this within the basic Scharnhorst design once the ship became much more heavy due to the guns. These kind of spiraling out of design changes is one of the reasons that you see ships from this period with what seem like really odd design choices, they were often driven by a desire to not completely rework the design. The example I often use for this is the 14 inch guns that are placed on the King George V class for the Royal Navy, the Royal Navy was aware that other navies had went with larger guns, but they were too late in the design process to change the guns without delaying the ships, so they just stuck with the smaller guns. For the Bismarck, with the complete redesign that had to be done the guns were actually increased up to 15 inches, or 380 mm, to match the French and Italians. The goal of a 33 knot top speed proved to be out of reach, and so the top speed was lowered to 30 knots, which would still be as fast as the Littorio class and faster than the Richelieu. All of this also meant an increase in total design displacement up to 40,000 tons, although the eventual actual displacement would be about 41,000 tons. As I always like to point out, I am unaware of a single capital ship class that actual matched its designed displacement after it was constructed, they all seem to come in a bit on the heavy side. Along with this large ship that they wanted to go real fast, the designers were back to a discussion of what kind of propulsion technology they wanted to use. For the Scharnhorst class the diesel engine had been abandoned, out of concern that they could not be scaled up enough to meet the demands of larger ships. But, when the German designers were allowed to design a new ship, the diesels reappeared. As it turns out there was a disagreement between the German ship design group, who really liked diesels, and most of the leadership of the German Navy, like Admiral Raeder, who preferred the more common steam turbine approach. In a fun twist, the design actually got quite far with the diesel engines still in it, and in fact it would still have diesels in 1935 not long before construction would begin. This would have been a one of a kind capital ship if such a design would have went forward, but then of course it didn’t. The change had to be made back to steam turbines when the manufacturer for the diesel engines backed away from its commitment that it would be able to build engines of appropriate size and power that would be able to work within the ship. This caused some design ripple effects, because the diesels provided one great advantage and that was range. In its diesel powered configuration the Bismarck had a designed range of an incredible 14,000 mile or 22,530 kilometer range. This would have far outranged the French and Italians, although to be fair to the Italians they listed range quite low on their priorities. The change back to steam power, meant that they had to be some design changes to allow for more fuel to be carried, and that would be done by changing some of the trimming tank capacity, tanks that could be filled with oil at the start of a cruise. This would allow for it to have an eventual range of about 8,500 miles, or over 13,500 kilometers. This put it roughly in line with what the French had designed for with the Richelieu. After the design was finalized and construction began, and even after construction was complete there would be several changes to the ship before and during the war. For example an Atlantic bow would be added to make it more capable of sailing in the rougher Atlantic seas. Radar would also be fitted on the ship, with the early German Naval radars focusing on surface search instead of aerial search. At the time this made sense because the radar was much more crude and less precise, and the early German radar had some problems identifying aircraft positions. Also during the mid 1930s giving a ship aerial radar was only sort of useful, the knowledge that an air raid was inbound could not really alter the course of action, as at the time there was not an accompanying carrier or some other method of rapidly increasing the protection from air attack. The only planes carried by the Bismarck would be 4 float planes used for spotting and reconnaissance.
The Bismarkc would be launched on February 14, 1939, in the spirit of Valentine’s day Hitler would pour out his love for the ship at the launching ceremony, saying “German designers, engineers, and shipyard workers have created the mighty hull of his proud giant which will ride the waves! May the German sailors and officers who have the honor utilizing this ship always prove to be worth of its namesake! May the spirit of the Iron Chancellor be transmitted to them, may it accompany them in all of their actions on their fortunate journeys in pace, but if it should ever necessary, may it lead them in the hardest hour of their fulfillment of duty.” It would then take about a year and a half before the ship was commissioned in August 1940 and the Kriegsmarine would have at its disposal the largest ship in the history of the German Navy, and the second largest that it would ever produce with the Tirpitz being just a bit heavier due to some design modifications. The question was, what should they do with it. This problems circles back a bit to what we discussed last episode, which was about how the Germans planned to use their new capital ships when it came to a war. Between the time that the ship was laid down, in July 1936, and when it came into service the entire outlook of the Kriegsmarine had changed. When it had been designed the primary enemy that it was aimed against was France but then it came into service during a war that involved the Royal Navy. The plan, as outlined by Raeder and accepted by Hitler and Blomberg, had been to use all of Germany’s surface vessels in various commerce raiding campaigns, but such campaigns were very different when launched against just France or when France had Britain as an ally. Just sheer weight of numbers caused problems in a conflict with the Royal Navy, and removed whatever small possibility of meeting the enemy ships on an equal footing or anything close to it. But the Bismarck had not really been designed from the beginning as a commerce raider, it was designed to meet primarily French ships in battle, and commerce raiding took a very different set of attributes. The biggest problems were speed and range, as outlined by German Captain Hellmuth Heye, who would describe the problem of using the German battleships in the commerce raiding capacity. “A breakup of the Battleship Unit to carry out cruiser warfare…is not possible so long as the individual battleship lacks superior speed and operational range to elude continuous contact and a combination of our opponents superior forces. Our individual battleships as presently constructed would soon fall victim to superior enemy forces without achieving commensurate successes.” You will note that Heye does not criticize the utility of having surface vessels that perform raiding duties on enemy commerce, just that Germany had created the wrong ships for the job. If a full commitment to surface raiding had been a decision made in 1935 instead of several years later, different decisions may have been made in the design. Speed and range probably would have been more prioritized, which would have spiraled out into all kinds of other changes. But it was not all bad, the Bismarck was still a powerful ship, and the Royal Navy would certainly be very concerned when it launched. My own opinion on it, and this is something we will dive into much more detail about when we get to the episodes on Operation Rheinubung and the sinking of the Bismarck in the future, is that while the ship may not have been the best surface raider, it was certainly a really good ship to cause the Royal Navy to pour a ton of time and resources into its pursuit and eventual sinking. But if the Bismarck class was not from the start designed for commerce raiding, but commerce raiding was seen as essential to German strategy, then we should probably talk about ships that were designed for such a purpose, or I guess boats, boats commonly prefaced by the letter U.
Up until this point in these two episodes I have not really mentioned U-boats, and of course they have to be discussed anytime you talk about the German Navy before or during the Second World War. They are probably the most famous contribution of the German Navy to the story of the war, or certainly are close. The German U-Boat campaigns of the First World War had been very successful at sinking ships in both the Atlantic and Mediterranean. In fact some of the most successful months of either war would be during the spring of 1917 after the resumption of unrestricted submarine warfare. This made them an important target during the Armistice and then peace agreements. In the Treaty of Versailles the Germans were forbidden from pursuing any further submarine use, and they were also banned from further construction and development of submarines. However, they would be able to circumvent some of these restrictions during the 1920s by setting up a design bureau in Holland called IVS, which would continue the process of designing and testing changes to the submarine designed used during the First World War. IVS would also use its knowledge of submarines to work with other nations that wanted to build submarines, which was a great way to continue to work through new ideas and to see them in practice. Many of the advancements made during this time period were not flashy, I might even go so far as to call them hidden improvements, things like shifting from a system where wires were used to control the submarine to one which was driven by hydraulics. These type of changes were important and were meaningful improvements to performance, while at the same time not being very news worthy. While IVS was good at some of these design changes, it did not solve all of the problems that the ban on submarine construction would cause, problems that were particularly problematic in the areas of industrial tooling and retaining skilled workers. There was a similar set of problems in all areas of naval construction in Germany and in other nations due to the drastic reductions in construction demands in the post war years, and then the continuing restrictions of the treaty system, but at least for other types of ships there was often at least some kind of construction project to hold over some workers, even if they were often much smaller projects. Germany had nothing similar to a U-boat to build, but all of that changed in 1932 when the German Navy began to plan to resume submarine construction in the following years. The first new prototype would be constructed in February 1935, and it would be built as secretly as possible, secrecy was considered so important that it was actually built outside of Germany, shipped into the country in pieces, and then assembled. The initial construction plans were relatively modest, with a fleet of 16 submarines being the first milestone. What is interesting is the small number compared with other ship types in the same construction plans. For example in the plan for 16 submarines was in the same construction program that saw the German navy create 6 battleships and an aircraft carrier. I like to point this out because, as we will discuss in just a moment, the German U-boat construction projects during the 1930s were always very modest in size. They were seen as complementary to the rest of the Navy, but in no way the most important part of the Kriegsmarine. This seems particularly odd given the role that they would later play int he war, and their reputation both during and after.
During 1938, at a time when they would have the Bismarck, Tirpitz, 3 heavy cruisers, an aircraft carrier, and several smaller ships the Germans would build just 9 medium sized U-boats, medium being the size that was most useful for their core commerce raiding function in the European and Atlantic waters where the bulk of shipping would be targeted. The next year, 1939 they would not do much better, with just 12 being originally planned. During these years Karl Donitz, who would be in command of the U-Boat forces, and later would replace Raeder at the head of the Kriegsmarine, constantly advocated for a larger emphasis on U-Boat construction, but specifically the types of U-Boats that he felt were best suited to the task of commerce raiding. Donitz believed that with a force of 300 medium U-Boats they would be able to sink a million tons of shipping per month. And if they could sink shipping on that level for an extended period any enemy, even the British would quickly simply run out of available shipping. The estimated shipping capacity available to Britain was around 17.5 million tons during the late 1930s. This type of math checked out if you believed in the ability of the U-boats to sink the numbers Donitz was estimating, But there was a disagreement between Donitz and some other German naval leaders around around kind of U-boats should be built to achieve the best results. Donitz heavily favored the medium designs particularly the Type VII which had been originally designed in 1933 and was really focused on what was seen as the best characteristics for a submarine that wanted to directly attack enemy shipping and then evade enemy defenses. Other leaders wanted more resources put into some of the larger designs, which would stage longer range patrons, with the downside that they were more lethargic when it came to their ability to maneuver. The ability to evade was seen as more critical due to the advancements in British Anti-submarine capabilities that had been growing during and after the First World War. The British would put a lot of faith in their ASDIC Sonar Technology, some would say too much faith as they believed that it was the perfect answer against any German U-Boat campaign. There were concerns in Germany that it might be really effective, but there was some hope that there could be tactics to get around the largest of the problems due to ASDICs limit range of around 1.5 miles. Not to dive too deep into the events of the war, but during its early stages ASDIC would prove to be less effective as a countermeasure than the British had hoped, and the German U-Boats would do quite well. However, they would never reached the numbers that Donitz believed was required for the U-boat campaign to be completely successful.
During 1938, and after Hitler announced Germany’s withdrawal from the Anglo-German Naval treaty on April 28th German naval planning began to consider the Royal Navy not just as a possible enemy in a future conflict, but its primary focus. The key caveat to this focus was that Hitler assured Raeder and the navy that there would not be a war with Britain until 1944. This kind of time horizon was important, because it would give 6 years for the Kriegsmarine to grow and expand its fleet before it would be called upon to go to war. Six years seems like a lot of time, but within the general schedule of naval rearmament it was much more limiting. To determine how to best utilize the time and resources available Raeder would ask Commander Hey, head of the Operational Section, to prepare a plan for that should be done in a war with Britain. Heye would favor the cruiser warfare approach that Germany would use during the Second World War, even if he did not believe that the ships that Germany had already built were completely suited to this approach. What he firmly rejected was any attempt by Germany to recreate the situation at the beginning of the First World War where the Imperial Navy had attempted to create a force that was designed to meet the Royal Navy in an open battle in the North Sea. Heye instead believed that any Jutland type scenario, or other major naval battle, should be avoided at all cost. Instead all surface resources would be prepared and used for commerce raiding, where they would augment the available U-boats, which Heye did not believe would be able to get the job done by themselves. To prepare the fleet for this role against the much larger Royal Navy there would have to be a massive expansion of the surface fleet, although all existing and under construction ships were also thought to be important pieces of that future fleet. This included the 2 Bismarck class and 2 Scharnhorst class battleships, the Deuschtland class Panzerschiffe, and the Hipper class heavy cruisers. Beyond these ships, several of which were still under construction, a new expansion plan was devised which would go through several iterations called Plan X and Y before the final plan, Z, was put into place. The overriding goal of the Plan Z designs was that they were to be technically better than whatever the British were building at the time, which was a requirement that came directly from Hitler. This would include 6 H-Class battleships, which would be larger than the Bismarck class in every way, with 16 inch guns inside a roughly 58,000 ton displacement. By 1944 the plan would be for four of those H-class battleships to be with the fleet, along with 4 updated Panzerschiffe, 2 Aircraft carriers, 4 new heavy cruisers, and many smaller ships. Planning would also extend beyong the 1944 date, with the number of Panzerschiffe increased up to 12, aircraft carriers up to 8, and heavy cruisers up to 24 by 1948. There would also be 194 U-boats by 1944 and 249 by 1948, with 88 of them being larger U-Boats and U-cruisers which Donitz hated. All of this represented a massive, massive expansion. I will not dive too deep into the details on a lot of these designs, in many cases they were larger and more capable than what the Germans had previously built, but they were also often in a relatively early stage by the time they were cancelled at the start of the war. The best example of this is that at least in some of the initial designs the Type-H battleships were back to diesel engines, the idea that would never die, even though I find it almost impossible that they would have stuck around until the final design. Instead, when the war did start even the very beginning phases of the expansion were not yet complete or even really started. Only a handful of the large ships would continue construction, and only the Bismarck, Tirpitz, and the cruiser Prinz Eugen would actually be completed, and they really came from the Pre-Plan Z expansion plans, not from Plan Z itself. While their dreams were big, at the end of the day they were just dreams, the reality was something quite different. I think the best place to end an episode on the preparations of the Kriegmarine is from this quote from Donitz that he would write a few days after the war started: “Seldom indeed has any branch of the armed forces of a country gone to war so poorly equipped. It could, in fact, do no more than subject the enemy to a few odd pinpricks.”