What if the Mackensen class battlecruisers (and possibly other large surface ships) had been given higher priority and completed during World War One? I think it’s an interesting POD because it seems plausible and impactful.
The German fleet of capital ships throughout the war sought to destroy the Royal Navy in detail to break the blockade. Fast capital ships therefore have a place within existing strategies. The other main naval strategy was commerce war by U-boats. I think the decision to focus on U-boats was not a given, because the German high command vacillated between the two strategies. I have read German battlecruiser construction was slowed by the diversion of resources to the U-boats. A change in priorities away from commerce war should speed battlecruiser construction, where it seems significant resources were invested IOTL seeing as multiple Mackensens were launched. In peacetime, it seems Grosscruisers were built in ~30 months. If this pace continued in war time, the HSF would start getting its new ships in mid-1917, which is also fortunately before the butterflies from no USW get too crazy. They might get the ships even earlier if they could accelerate from their peace timetable which is something the British did with the Renown class.
Speaking of the British, we already probably have a good idea of what they would have done in response: all the same things they did IOTL because they assumed the Mackensens were being completed in a timely fashion. AIUI initially the Admiralty expected the Queen Elizabeth class to be consistently 25 knot fully armored battlecruisers rather than the at-best 24 knot battleships they got, so they weren’t really aware of the potential for a “battlecruiser gap” until the QEs came into service in 1915, leading to the Hood being laid down in mid 1916.
So in mid-1917 (with only a small butterfly net) the Germans might have have Von der Tan, Moltke, Seydlitz, 2 Derfflingers (Hindenburg complete with Lutzow sunk at Jutland) and 2 Mackensens. The Royal Navy might have only 3 surviving ships (Lion, Tiger, and Princess Royal) designed for BC-on-BC combat after Queen Mary was sunk at Jutland, and even they aren’t looking super hot in a matchup against Mackensens. The 4 remaining I-class dreadnought armored cruisers are downright obsolescent against a German scouting force with Mackensens, and the Courageous and Glorious were simply not designed for that task. The Repulse and Renown might be able to hold their own after their post-Jutland armor enhancements, but still aren’t ideal. Those Royal Navy ships have to hold the line for at least 6 months, because the Admiral-class (essentially designed as Mackensen killers) should be constructed faster without Unrestricted Submarine Warfare, but could probably never be ready before 1918.
Miscellaneous:
Do Saschen and Württemburg get built by 1917 too? What about Salamis, potentially constructed as a battlecruiser? Does the Royal Navy reconstruct Furious with 15 inch guns if they’re short on battlecruisers?
The German fleet of capital ships throughout the war sought to destroy the Royal Navy in detail to break the blockade. Fast capital ships therefore have a place within existing strategies. The other main naval strategy was commerce war by U-boats. I think the decision to focus on U-boats was not a given, because the German high command vacillated between the two strategies. I have read German battlecruiser construction was slowed by the diversion of resources to the U-boats. A change in priorities away from commerce war should speed battlecruiser construction, where it seems significant resources were invested IOTL seeing as multiple Mackensens were launched. In peacetime, it seems Grosscruisers were built in ~30 months. If this pace continued in war time, the HSF would start getting its new ships in mid-1917, which is also fortunately before the butterflies from no USW get too crazy. They might get the ships even earlier if they could accelerate from their peace timetable which is something the British did with the Renown class.
Speaking of the British, we already probably have a good idea of what they would have done in response: all the same things they did IOTL because they assumed the Mackensens were being completed in a timely fashion. AIUI initially the Admiralty expected the Queen Elizabeth class to be consistently 25 knot fully armored battlecruisers rather than the at-best 24 knot battleships they got, so they weren’t really aware of the potential for a “battlecruiser gap” until the QEs came into service in 1915, leading to the Hood being laid down in mid 1916.
So in mid-1917 (with only a small butterfly net) the Germans might have have Von der Tan, Moltke, Seydlitz, 2 Derfflingers (Hindenburg complete with Lutzow sunk at Jutland) and 2 Mackensens. The Royal Navy might have only 3 surviving ships (Lion, Tiger, and Princess Royal) designed for BC-on-BC combat after Queen Mary was sunk at Jutland, and even they aren’t looking super hot in a matchup against Mackensens. The 4 remaining I-class dreadnought armored cruisers are downright obsolescent against a German scouting force with Mackensens, and the Courageous and Glorious were simply not designed for that task. The Repulse and Renown might be able to hold their own after their post-Jutland armor enhancements, but still aren’t ideal. Those Royal Navy ships have to hold the line for at least 6 months, because the Admiral-class (essentially designed as Mackensen killers) should be constructed faster without Unrestricted Submarine Warfare, but could probably never be ready before 1918.
Miscellaneous:
Do Saschen and Württemburg get built by 1917 too? What about Salamis, potentially constructed as a battlecruiser? Does the Royal Navy reconstruct Furious with 15 inch guns if they’re short on battlecruisers?