The H39-Class battleship Hindenburg is my best scratch build model so far. Since I was fascinated by those big Bismarck class successors, I wanted to build one for quite a long time. As the general appearance had much similarities to the Bismarck or Tirpitz , it could easily done by using two Revell Tirpitz and one Monogram Bismarck  kits. The forward superstructure (command tower) had to be slightly modified and moved a bit forward, while the afterwards superstructure (second funnel and hangar complex) had to build from scratch. The remaining parts of this kits were later used to build the Schneidheim and the Odin . 

The six battleships of the H-class were the projected successors of the battleships Bismarck and Tirpitz .

Those ships, which would have been the core of the fleet build according to the Z-Plan, were mainly enlarged and improved versions of their predecessors. In difference to them, those ships were planned with commerce war in mind, therefore diesel engines were selected instead of the usual high pressure steam engine used by the German navy in those days.

Design of these ships started in 1937, and a total construction time of 50 months was projected to complete a ship of this class. All ships were scheduled to be completed by 1944. Only two of the ships were actually started, Schlachtschiff H at Blohm & Voss, Hamburg on June 15th, 1939 and Schlachtschiff  J at AG Weser, Bremen on August 15th, 1939. Construction was stopped on October 10th, 1939 as the focus in German naval construction switched to the construction of more U-boats instead of battleships. Up to this day, 1200 tons of steel was already used for the Schlachtschiff  H , 3500 tons were in construction and another 12000 tons were already ordered. (Schlachtschiff  J was still in an earlier phase of construction). In 1940, the used material was wrecked on the shipyard and used elsewhere.

Although it was obvious that Germany would not be able to build a complete new battleship during wartime, the plans for the H-class battleships were further developed and improved, to study the design of a competitive battleship and increase sheer ship scale to counteract increasing bomb weights. Lessons learned in naval conflicts including German warships, like Norway, the sinking of the Bismarck and the loss of the Scharnhorst were used to upgrade the plans, so the size of the later H-class designs increased in a very spectacular way. Comparing the basic data of the different H-class designs shows this very effectively, as shown in the table below:

Design	Size / Length	Artillery	Performance / Speed
Tirpitz	52.600 tons 251 m	8 x 38 cm	163.000 shp  30.8 kn
H39	62.497 tons 277,8 m	8 x 40,6 cm	165.000 shp  30,0 kn
H40A	65.600 tons 282,9 m	6 x 40,6 cm	230.000 shp  32,2 kn
H40B	70.000 tons 299,8 m	8 x 40,6 cm	240.000 shp  32,3 kn
H41	76.000 tons 300,4 m	8 x 40,6 cm	165.000 shp  28,8 kn
H42	98.000 tons 305,2 m	8 x 40,6 cm	270,000 shp  32,2 kn
H43	120.000 tons 330,2 m	8 x 50,8 cm	270.000 shp  31,0 kn
H44	141.500 tons 345,1 m	8 x 50,8 cm	165.000 shp  30,1 kn
CVN John C. Stennis, completed 1995	102.000 tons 332,9 m	none	280.000 shp  30,0+ kn

It is obvious that everything after the H40 was far from realization. The H44 would have been bigger than the latest U.S. Nuclear Aircraft Carrier, the John C. Stennis . There even would have been no usable port for a H44 in Germany.