History of the H-Class
The H class of battleship is not actually a singular class of battleship but a series of planned battleships for the Kriegsmarine before the Second World War, these ships were quite literally larger Bismarcks with the ship being focused on here, H-39 having 16" inch guns however her primary and secondary layout was the same as the Bismarck class.
As for the story behind the H class, they were apart of Plan Z which was the plan to bolster the Kriegsmarine's surface fleet, the plan itself was the successor plan from the previous plan X which was more of a draft followed by plan Y with plan Z succeeding plan Y. Plan Z called for the following: 90 torpedo boats, 68 destroyers, 22 scout cruisers, 13 light cruisers, 5 Heavy cruisers (just the 5 admiral hipper class ships), 15 Panzerschiffe (ships similar to the Deutschland class), 4 aircraft carriers, 3 battlecruisers (no this is not the Scharnhorst class, this is made up of the O-class), and 10 battleships.
As the focus is on the H-39 for the H-class, plan Z called for the 2 Scharnhorst class, both Bismarck class ships, and then the other 6 would consist of ships of the H-class ships which were as mentioned previously was not a singular class of ship and if they were would make even the French look normal when it came to tweaking their designs for each ship of the class, H-39 design was basically a larger version of the Bismarck class with 16 inch guns like the other H-class ships would be designed. In terms of armament of the H-39 design was very similar to their predecessors with the exception of the main battery being 16" inch guns over the previous 15" inch guns, the secondary battery would be exactly identical with 12 150mm guns in twin turrets with 3 per side on the ship with 2 turrets located near the bridge superstructure, 2 turrets located more near the first funnel, and the last 2 more closer to the 2nd funnel. The AA battery would contain 16 105mm guns in the same twin mounts as found on Bismarck, in terms of AA guns the ship was planned to use 16 37mm and 24 20mm AA guns. To round off the weapons the H-39 would have unlike Bismarck or Tirpitz would have 6 underwater torpedo tubes in the bow even though every major naval power had seen the common sense to eliminate them from their own Battleships with the exception of the British who did remove them from many of their Dreadnought battleships but the designers decided to give their Nelson class the underwater torpedo tubes because why not. The ships would retain the 3 propeller arrangement which was in fact a design flaw as seen on what happened to Bismarck, the ship was to be powered by 12 MAN 9 cyl Diesel engines with 4 per propeller shaft giving them 165,000 shp giving them a designed speed of 30 knots, the ship also had 3 rudders in total with 1 main rudder alined with the keel and center propeller shaft and 2 smaller wing rudders. Armor would be similar to the Bismarck with 300mm for the main belt and 145mm for the upper belt, 220mm for the bulkheads, 385mm to 150mm of armor for the main turrets which is slightly greater than the Bismarck classes turrets, 365mm for the barbettes, 350mm to 200mm for the conning tower tower, 50mm to 80mm for the upper decks and 100mm to 120mm for the main armor deck, as well as 45mm for the torpedo bulkheads.
Fate of the H-39
Similar to the issue the French had where they had a limited amount of shipyards that were capable of building such ships, in the Germans case they only had 4 capable to building them, 2 ships would have their keels laid down under the designations Schlachtschiffe H and Schlachtschiffe J.
Schlachtschiffe H was laid down in mid July, 1939 while Schlachtschiffe J was just laid down in the beginning of September which would be the same month that Germany would invade Poland and as such work was suspended on both ships as it was viewed that the ships would not be completed until the war ended, in the end neither ship would come close to completion as resources were prioritized for the Luftwaffe as well as the Army. One caveat however was that the guns meant for the class would be built and used as costal guns with at least 10 guns made with a total of 7 being deployed in Norway, and another 3 used in Poland before being dismounted and used in France which appeared to have been later were scrapped but the guns in Norway had a different fate as only 3 of the guns would be scrapped while the other 4 were kept around of which one of these guns is open now a museum.
Despite work on the ships coming to a complete halt in 1941 the design of the H-class would be revised now known as H-41 which was not to modify the existing design of the H-39 but as an improved design so no ships of the modified or subsequent designs which would follow a trend of being even larger than the last would ever be laid down or have any parts made for them making the H-39 class the most advance German battleships that were designed and began construction