The Kriegsmarine's mixed diesel and steam baseline

Submarines, torpedo boats, and Deutschland-class ships already used diesel, while destroyers, the Scharnhorst and Bismarck classes, and much of the surface fleet relied on steam. The Königsberg and Leipzig classes show that German designers were already experimenting with combined diesel and steam arrangements. Their diesels served cruising needs while steam machinery supplied high speed, creating a route toward larger diesel warships. This counterfactual redirects engineering effort from advanced high-pressure steam machinery to the development of large diesels. The existing experience makes a diesel emphasis plausible and also shows the complexity of a hybrid plant.