With the progress of the war, the further development of the German battleship design studies were influenced by the experience learned by the lessons of the ongoing seawar. Especially the loss of the battleship Bismarck had a huge inpact on the construction office of the Kriegsmarine.
The plans for the battleship H42 were focused on a better protection of the ship. Based on the design H41, the armament was kept identical, but the armor protection was again increased, leading to a projected ship size of 80000 t. The increased protection was achieved by thickening and enlarging the complete armor scheme, but also in improving the underwater protection against torpedo and mine hits.
Because of the lethal torpedo hit on the Bismarck the stern of the ship should be protected by two fins, protecting the props and rudders from the side, but it is questionable if this system would provide the required manouverability for the ship. Since the performance requirments still called for a top speed of 32 kn, the traditional three prop arrangement would not be sufficient enough to propulse the ship, therefore a 4 prop system was choosen, two of them powered by diesel engines, the other two powered by steam turbines.