Bismarck Class Battleship - Bismarck Class Design

Bismarck Class Design

A series of conceptual designs were begun in 1932 to determine the ideal characteristics of a battleship built to the 35,000 long tons (36,000 t) limit of the Washington Naval Treaty. These early studies determined that the ship should be armed with eight 33 cm (13 in) guns, have a top speed of 30 kn (56 km/h; 35 mph), and have strong armour protection. The actual design work for what became the Bismarck class was begun in 1933 and continued until 1936. In June 1935, Germany signed the Anglo-German Naval Agreement, which allowed Germany to build battleships at a ratio of 35 percent to the total tonnage of the Royal Navy. At the time, France, which had begun a program of naval expansion, was viewed as the most likely threat, not Great Britain. As a result, Bismarck and Tirpitz were intended to counter the new French battleships being built at the time. A series of questions needed to be answered during the design process, including the calibre of the main battery, the propulsion system, and armour protection.

The deciding factor for the adoption of 38 cm (15 in) guns for Bismarck and Tirpitz was the decision of the French Navy to arm its four Richelieu class ships then under construction with 38 cm pieces. It was decided that four twin turrets would provide the best solution to distribution of the main battery, as it would provide equal firepower forward and aft, as well as simplify fire control. The naval constructors examined diesel geared drive, steam drive, and turbo-electric drive engines; the last system was the preferred choice, as it had been extremely successful in the two American Lexington class aircraft carriers and the French passenger ship Normandie.

The design staff were also required to provide sufficient range to the new battleships; they would have to make long voyages from German ports to reach the Atlantic, and Germany had no overseas bases where the ships could refuel. Due to the numerical inferiority of the German fleet and the assumption that naval battles would take place at relatively close range in the North Sea, the Bismarck design placed great emphasis on stability and armour protection. Very thick vertical belt armour was adopted, along with heavy upper-citadel armour plating and extensive splinter protection in the bow and stern of the ships.

The displacement of Bismarck and Tirpitz were limited by the capabilities of existing infrastructure in Kiel and Wilhelmshaven, and the Kaiser Wilhelm Canal. On 11 February 1937, the Construction Office informed Generaldmiral Erich Raeder that the ships could not displace more than 42,000 long tons (43,000 t) due to the constraints of the harbour and canal depths. The Office also expressed a preference for building a third vessel and remaining within the 35,000-ton treaty limit. Admiral Werner Fuchs, the head of the General Command Office of the Oberkommando der Marine, advised Raeder and Adolf Hitler that a series of modifications would be necessary to reduce the displacement to ensure the new ships met the legal requirements of the London Naval Treaty. Japan, however, refused to sign the new treaty, and so on 1 April 1937 an escalator clause permitting treaty signatories to build ships up to a limit of 45,000 long tons (46,000 t) went into effect. The final design displacement of 41,400 long tons (42,100 t) was well within this limit, so Fuchs's modifications were discarded.