I have been interested in the German H class battleships for some time but info has been hard to get. I do know that prewar Hitler had demanded 20-21 inch guns for a 70-80,000 ton super battleship but the Naval Staff convinced him that 16 inch gun battleships of the proposed H class would meet the needs of Kriegsmarine and were more practical in terms of port facilities. But what kind of ships would be if they were built. I know that German battleships of the H class of 55,000 (?) tons were under construction when the war broke out and were cancelled along with the aircraft carrier. I also read about the requirement for all major units to have diesel or mixed diesel/steam plants and thus have very great cruising ranges inspired by the success of the pocket battleships and be capable of 29 knots maximum speed.
Japan's Yamato class had nine eighteen inch guns as main armament, five and six inch secondary batteries, I think and a couple of eight inch turrets but I have to refer to my books to remember that along with light AA guns while torpedo tubes are something that my book is not sure of.
What do you think that the super battleships characteristics might have been if they had been built. Please feel free to speculate.