The thinking behind my proposal was that it might put less pressure on the German shipbuilding industry and therefore more ships would be completed.
IOTL the Germans began 9 major warships (2 Graff Zeppelins, 2 Bismarcks and 5 Hipper class) of about 206,000 tons standard displacement.
Had all gone to plan:
Graff Zeppelin, Hipper, Blücher and Prinz Eugen would have been completed before World War II broke out;
Bismarck would have been completed in October 1939; Aircraft Carrier B in November 1939; Seydlitz in January 1940; Tirpitz in February 1940 and Lützow in July 1940.
The aircraft carriers would have taken an average of 32 months to build, the battleships 39 months and the heavy cruisers 36 months. The projected completion dates are from M.J. Whitley's books.
However, German industry could not meet the schedule.
Only the Hipper had been completed by the time war broke out (April 1939 instead of July 1938). Blücher and Prinz Eugen were not completed until late September 1939 and August 1940 respectively (instead of October 1938 and May 1939). The average delay on the 3 heavy cruisers that were actually completed was 12 months.
The battleships were also completed about a year behind schedule in August 1940 (Bismarck) and February 1941 (Tirpitz).
Neither of the aircraft carriers was completed, but according to Whitley the Graff Zeppelin was 88% complete when work was suspended in June 1940. Her completion was scheduled for the end of 1940. If she had been completed then she would have taken 48 months to build, but would not have been capable of operational employment for about another year because some of her armament and fire control equipment had not been fitted.
The Anglo-German Naval Agreement gave the Germans enough tonnage to build a 3rd 35,000 ton battleship. In October 1935 they planned to lay Battleship H down in October 1937 for completion in January 1941 (39 months). When the British announced the Lion class the Germans had enough tonnage for a fourth 35,000 ton battleship, which (in January 1937) they planned to lay down in May 1938 for completion in 3½ years (November 1941). Incidentally the British King George V and Prince of Wales were laid down in January 1937 for completion by 1st July 1940 which was also 3½ years.
But, Battleships H and J were not laid down until July and August 1939 respectively. Whitley said part of the delay was in part due to no slipways being available, but that the major cause of the delay was because the Germans spent too much time designing the ships.
He also attributes the Germans laying down no more cruisers after Kreuzer L (Seydlitz) to them spending an excessive time agreeing on the specification of what became Cruiser M. According to him Cruisers M to P were ordered in May 1938, with Cruiser M scheduled to be laid down in November 1939 for completion in May 1942 (30 months).
However, if the Germans had decided to build Battleships H and J as improved Bismarcks and agreed the specification of the Cruiser M class in reasonable time the overloading of the shipyards would have been even worse.
In This Timeline
My proposal was that the Germans still lay down 9 major warships, but that they lay down 3 Bismarcks and 6 light cruisers of 8,000 tons for a total of 171,000 tons (instead of 2 aircraft carriers, 2 battleships and 5 heavy cruisers for a total of 206,000 tons). That is the same number of hulls, but hopefully less strain on the shipyards.
I thought 6 light cruisers of 8,000 tons standard displacement would be a better investment than the 5 Hippers because:
-48,000 tons of structural steel and armour instead of 70,000 tons - the surplus would go towards Battleship H;
-The main armament might be easier to produce. Three triple 5.9" turrets (18 total) or four twin 5.9" turrets (24 total) versus four twin 8" turrets (20 total). If the former was chosen it might be quicker to produce as its a design that is already in production. If the latter I thought there might be some economies of scale as it was also being built for the Scharnhorst and Bismarck classes;
-The light cruisers might be easier to build. The projected building time for a Hipper class was 36 months and the projected building time for the Kreuzer M class was 30 months. Leipzig and Nurnberg were both completed in 24 months, albeit when the shipyards were less congested;
-An improved Nurnberg or Kreuzer M would be more useful operationally. They would be more useful for commerce raiding due to their combined steam and diesel machinery (COSAD) which gave them greater endurance. Furthermore it should be more reliable than the high-pressure steam plants used by the Hipper class as theoretically they would cruise on their diesels with the steam plant as a boost engine for maximum speed.
-They had less firepower and were less heavily armoured, which would make them easier to sink, but I thought some of this could be overcome by having them operate in pairs. That is the higher rate of fire of sixteen 5.9" would offset the longer range and hitting power of eight 8".
Substituting a third Bismarck for the two aircraft carriers was on the grounds that even if Graff Zeppelin and Aircraft Carrier B had been completed on schedule it is likely that they would not have been effective warships as they were the Germans first attempt at building aircraft carriers. Even if they had got it right first time it would have taken longer than normal for them to become operational because the Germans would be learning the operating techniques from scratch.
Therefore in the short term they would convert a merchant ship to gain design and operating experience. The Germans (if they hadn't already IOTL) would also send Kriegsmarine and Luftwaffe personnel for training on aircraft carriers and carrier aircraft with the Imperial Japanese Navy. Similarly personnel from the aircraft industry and Kriegsmarine warship designers would go to work in the Japanese aircraft industry and IJN warship design department to gain experience of carrier aircraft and aircraft carrier design respectively.
The accumulated experience would go towards the long term plan which would be a class of 4 aircraft carriers that would be build in the first half of the 1940s and the aircraft that would operate from them. IOTL the Germans planned (in May 1938) to order Aircraft Carriers C and D in April 1941, lay them down in July 1941 and complete them in July 1944. ITTL they would be preceded by Aircraft Carriers A and B ordered in April 1939 (in place of the real Battleships H and J) for completion in the third quarter of 1942.
Therefore
Battleships F (Bismarck) and G (Tirpitz) would still be ordered on 16th November 1935 and 14th June 1936 respectively. Bismarck would still be laid down on 1st July 1936 for completion on 1st October 1939 and Tirpitz would still be laid down on 2nd November 1936 for completion on 1st February 1940.
Battleship H would be ordered on 16th November 1935 and laid down at Germania on 30th September 1936 in place of Aircraft Carrier B, with 1st January 1940 as its planned completion date.
The five light cruisers ordered in place of the Hipper class would be laid down at the same yards on the same dates with their projected completion dates advanced by 6 months each, i.e. from January 1938 to January 1940.
The sixth light cruiser would be ordered on 16th November 1935 in place of Graff Zeppelin. She would be laid down at Deutsche Werke on 28th December 1936 in place of Graff Zeppelin with a projected completion date of 1st July 1939.
It would not be possible to complete any of the above to schedule.
The light cruisers would be completed an average of 6 months late (total time to build 36 months) instead of 12 months late for the Hipper class (total time to build 48 months). Therefore at least 2 would have been completed before the outbreak of World War II, the second pair in September 1939 and the final pair by August 1940.
Furthermore, I was hoping to have Battleship H completed in January 1941 (51 months like Bismarck and Tirpitz).
The Follow On Programme
Also the British announcement of the Lion class would allow the Germans to order Battleship J in January 1937. To speed up delivery she was to be a repeat Bismarck to be laid down on 1st October 1937 and completed on 1st February 1941. That was the original (October 1935) schedule for Battleship H, but as she was laid down in September 1936 ITTL Battleship J can take her place.
Plan Z would be for a fleet the same size as OTL, but there would be some differences in detail.
There would still be 4 aircraft carriers, but as already explained Ships A and B would be laid down in 1939 for completion in 1942 while in accordance with OTL Ships C and D would be laid down in 1941 for completion in 1944.
There would still be 8 battleships and 5 battlecruisers, but instead of 2 Bismarck and 6 H class there would be 4 Bismarck and 4 K class (built to the H class design of OTL). All other things being equal Battleships K, L, M and N would be ordered on 25th May 1939 and the orders for battlecruisers O, P and Q would be ordered on 8th August 1939.
The plan would still be for 30 cruisers by 1944. However, instead of 13 heavy and 17 light cruisers the plan would be for 12 heavy and 18 light cruisers. ITTL the Germans already had 12 light cruisers completed or under construction instead of 5 heavy and 6 light cruisers. In 1938 they decided to build the balance of 6 light cruisers before proceeding to the 12 heavy cruisers. Therefore Cruisers N to S were ordered to the 8,000 ton light cruiser design built in place of the Hipper class. IOTL Cruisers M to P were ordered in May 1938, but N, O and P were ordered in 1937 followed by Q, R and S in 1938 ITTL.
However
We know that World War II is going to break out in September 1939. Other threads on the site have suggested that although Hitler told his generals and admirals to prepare for war in 1944 he knew that he had to make war before Germany lost his lead in the European arms race that he had started. This means that the Germans have to use the Anglo-German Naval Agreement to get the strongest possible surface fleet for about 1940 instead of 1944. That what was behind my idea to build a third Bismarck instead of the aircraft carriers and light cruisers instead of heavy cruisers.
Therefore after the Munich Crisis the Germans should have concentrated their resources on completing the ships that were already under construction rather than start to build ships that had no chance of completion.
In practice this would mean not ordering the 4 aircraft carriers, 4 battleships and 3 battlecruisers that would otherwise be ordered in 1939 ITTL to concentrate the available resources on the 4 battleships that were already under construction. However, at least 3 of the 6 light cruisers ordered in 1937 and 1938 would be laid down 1938-39 with the intention of completing them in 1941. Some of the turrets would come from ordering Z-23 to Z-42 as Type 1936B destroyers armed with five 5" guns in single mountings instead of Type 1936A ships with five 5.9" guns in one twin and three single mountings.
Summary and Conclusions
IOTL the Germans ordered 2 aircraft carriers, 2 battleships and 5 heavy cruisers between October 1934 and July 1936. They managed to complete both battleships and 3 of the cruisers between April 1939 and February 1941.
ITTL the Germans ordered 3 battleships and 6 light cruisers over the same period. The 3 battleships would be completed between August 1940 and February 1941. The 6 light cruisers would be completed between April 1938 and July 1940. The Battleship H was built in about 51 months like Bismarck and Tirpitz. The light cruisers were built in an average of 36 months instead of the 48 months it took to build Hipper, Blücher and Prinz Eugen.
Germany should have the resources to do this because:
-The 9 ships that were begun IOTL had a combined displacement of 206,000 tons. The 9 ships begun ITTL had a combined displacement of 171,000 tons so less structural steel and armour is required.
-A Graff Zeppelin class aircraft carrier was actually longer than a Bismarck class battleship so it should be possible to lay down Battleship H on the slipway used for Aircraft Carrier B.
-The Graff Zeppelin class had more powerful machinery than the Bismarck class and the Hipper class had more powerful machinery than the 8,000 ton light cruiser. Therefore it should be easier to produce the machinery for 3 Bismarcks and 6 light cruisers than it was for 2 Graff Zeppelins, 2 Bismarcks and 5 Hippers.
-IOTL the Germans had launched 8 of the 9 ships by September 1939, which as far as I know included fitting their armour and machinery. I don't know how far advanced the structure of Aircraft Carrier B was or if her machinery had been installed. However, I think it is reasonable to assume that the Germans would have at least been able to launch 9 out of 9 ships by September 1939 ITTL.
Therefore the Germans could have built the hulls and machinery. Could they have built their armament, fire control and fitted them out in time?
In the case of the light cruisers I think the answer is yes:
-The main turrets should be easier to be produce;
-They had a much lighter AA armament of two twin 88mm instead of six twin 105mm and presumably fewer AA directors too.
For Battleship H it would have been harder:
-The 3 Hipper class completed IOTL had a combined armament of eighteen twin 105mm and the 6 light cruisers built in their place ITTL required twelve twin 88mm. Therefore the six surplus mounts and their fire control equipment would provide 75% of the heavy anti-aircraft armament of Battleship H;
-But then there are the four 15" and six 5.9" turrets plus their associated fire control equipment. The twin 5.9" is in large scale production with: 24 being built for Cruisers G to M (instead of 20 twin 8" for the Hipper class); 8 being built for Scharnhorst and Gneisenau; and 12 being built for Bismarck and Tripitz for a grand total of 54 turrets. Therefore I think they could squeeze in another 6 for Battleship H. If Saphroneth is correct about the lack of gun pits for the main armament then it's not possible to build the 15" turrets in time to complete her in January 1941.
For the follow on programme:
-(Based on how long it took to build Bismarck and Tirpitz), Battleship J if laid down in October 1937 would be launched in February 1940 and completed in February 1942. However, its more likely that she would have been suspended when she reached the fitting out stage to concentrate resources on completing her sister ships;
-The 6 repeat light cruisers would do better. At least 3 of them would be completed. This is in part because the 6 light cruisers built in place of Graff Zeppelin and the Hipper class were launched in an average of 18 months instead of 24 months, which freed up slipways for the repeat ships. Furthermore they were all completed in an average of 36 months instead of 48 months for the 3 Hipper class that were completed, which in turn freed up fitting out births for the repeat ships.