History of Bismarck battleship (part 3)

History of Bismarck battleship (part 3)

BISMARCK'S DESIGN Introduction.

Contrary to what some authors have suggested, the origin of the design of the Bismarck Class battleships had nothing to do with the Bayern Class of World War I except for the fact that they were also equipped with eight 38cm guns in four twin turrets and a three-shaft propulsion plant. The battleships of the Bismarck Class were the product of a warship development that had begun with the construction of the pocket battleships (Panzerschiffe) of the Deutschland Class in the late 20's and early 30's under the restrictions of the Treaty of Versailles.Historical Background.

The Treaty of Versailles of 1919, stated in its Article 181 that the German naval forces in commission could not exceed six battleships, six light cruisers, twelve destroyers and twelve torpedo boats, while Article 190 limited the displacement of capital ships to 10,000 tons. On 6 February 1922, the United States, the British Empire, France, Italy and Japan, signed the Washington Naval Treaty. Under the terms of this treaty, the five major naval powers agreed to limit the standard displacement of their capital ships to 35,000 tons (35,560 metric tons), and the calibre of their heavy guns to 16 inches (40.6cm). The total capital ship standard tonnage was distributed as follows: ·  United States 525,000 tons (533,400 mt).
 ·  British Empire 525,000 tons (533,400 mt).
 ·  France 175,000 tons (177,800 mt).
 ·  Italy 175,000 tons (177,800 mt).
 ·  Japan 315,000 tons (320,040 mt).

The London Naval Conference of January-April 1930 was intended to review the Washington Naval Treaty, but France and Italy refused to ratify it because of the low battleship tonnage ratios they were assigned.

In the early 30's, German naval ship building was still restricted by the Treaty of Versailles, and it was not until 18 June 1935 when Britain's Foreign Minister Sir Samuel Hoare and the German Ambassador Joachim von Ribbentrop signed the Anglo-German Naval Agreement in London, that its restrictions were finally lifted. Germany was then allowed to build a surface fleet of up to 35 per cent of that of Britain, and up to 45 per cent in the case of submarines. This meant that Germany could now build 184,000 tons of battleships, in other words five 35,000-ton battleships. Between December 1935 and March 1936 the five major powers met again in London. Japan withdrew from the conference since her demands for parity with the United States and the British Empire in capital ship tonnage were not met. So, an escalator clause was added, and allowed to build battleships of up to 45,000 tons in case a non-signatory power was suspected of building ships outside the treaty limits. Since Italy and Japan did not sign the Treaty, the standard displacement of 45,000 tons was understood to be acceptable by the other powers including Germany.The Bismarck Class.

After the Anglo-German Naval Agreement was signed, the battleship "F" (later Bismarck) was officially ordered, and the building contract placed on 16 November 1935 with the shipbuilding firm Blohm & Voss, founded by Hermann Blohm and Ernst Voss in 1877. Designed by Dr. Hermann Burkhardt, the battleships "F" and "G" (Bismarck and Tirpitz) were basically improved versions of the battleships "D" and "E" (Scharnhorst and Gneisenau), and featured many of the details of their predecessors. The Bismarck looked like an enlarged Scharnhorst indeed. Officially listed as a 35,000-ton battleship to comply with the London Treaty, Bismarck's real displacement was actually some 7,000 tons higher. According to the 1937 escalator clause this was well within the 45,000-ton limit. Moreover, none of the other naval powers kept themselves inside the 35,000-ton limit either, and all the battleships that came out of the 1936 London Treaty (Vittorio Veneto, Richelieu, King George V, and North Carolina) exceeded this limit.

More than 90% of the ship’s hull was electrically welded. Special care was put to the stability of the ship, and one of the most outstanding characteristic of the new Bismarck Class was its superb capability to absorb damage due to the protected volume. The subdivision was very extensive, and the hull was divided into 22 watertight compartments/sections (Abteilungen) numbered I-XXII from stern to bows. 17 of those compartments were within the citadel; this meant that 70% of the waterline length was protected by heavy armour. The design required a very wide beam of 36 meters which also contributed to maintain a high degree of stability. The ship comprised 17 decks from the keel to the foretop:· Foretop (Vormars).
· Searchlight deck (Scheinwerferdeck).
· Lower searchlight deck (Unteres Scheinwerferdeck).
· Admiral’s bridge (Admiralsbrücke).
· Upper mast deck (Oberes Mastdeck).
· Lower mast deck (Unteres Mastdeck).
· Bridge deck (Brückendeck).
· Lower bridge deck (Unteres Brückendeck).
· First deck (Aufbaudeck).
· Upper deck (Oberdeck).
· Battery deck (Batteriedeck).
· Main deck / Armour deck (Zwischendeck [tweendeck] / Panzerdeck).
· Upper platform deck (Oberes Plattformdeck).
· Middle platform deck (Mittleres Plattformdeck).
· Lower platform deck (Unteres Plattformdeck).
· Stowing [stowage] (Stauung).

In contrast with the Scharnhorst, the lower main belt of the Bismarck was reduced in thickness from 350 mm to 320 mm (Tirpitz 315 mm). A 320 mm belt backed by a 110-120 mm sloped armour deck was considered more than enough to defeat any projectile at any distance, and made the battleship practically immune in close range engagements. The upper belt, was however, increased in thickness up to 145 mm and had no portholes. Underwater, the thickness of the torpedo bulkhead remained the same, but the distance between this and the outer hull was increased from 4.5 to 5.5 meters amidships.

Scharnhorst cross section

Bismarck cross section

The new design had to be longer due to the fourth battery turret. The traditional arrangement of four twin turrets was selected. Although 40.6cm main guns were permitted by the 1936 London Naval Treaty, the new and powerful 38 cm SK C/34 with a high muzzle velocity was considered more than adequate to fulfil its purposes. Germany did not have 40.6cm guns available at that time anyway. The secondary artillery was to be the same as in the Scharnhorst Class, however the use of single turrets amidships was abandoned in favor of twins.
DESIGN DETAILS

	Scharnhorst	Bismarck
Displacement:  ·  Official:  ·  Standard:  ·  Full load:	26,420 mt 32,060 mt 38,430 mt	35,560 mt 41,700 mt 50,900 mt
Dimensions:  ·  Waterline length:  ·  Beam:  ·  Draught:	226 meters 30 meters 8.6 meters	241.5 meters 36 meters 9.3 meters
Armour protection:  ·  Upper belt:  ·  Lower main belt:  ·  Main turrets:  ·  Upper deck:  ·  Third armour deck:  ·  Conning tower:  ·  Torpedo bulkhead:  ·  Protected length 1:  ·  PC/TC 2:	45 mm 350 mm 100-340 mm 50 mm 80-110 mm 200-350 mm 45 mm 68% (153 meters) 16/21	145 mm 320 mm 130-360 mm 50-80 mm 80-120 mm 220-350 mm 45 mm 70% (170 meters) 17/22
Armament:  ·  Main:  ·  Secondary:  ·  Anti-aircraft:	9 x 28cm/L54.5 12 x 15cm/L55 14 x 10.5cm/L65 16 x 3.7cm/L83 14 x 2cm	8 x 38cm/L52 12 x 15cm/L55 16 x 10.5cm/L65 16 x 3.7cm/L83 18 x 2cm
Propulsion plant:	12 Wagner boilers Three turbine sets 125,000 hp	12 Wagner boilers Three turbine sets 138,000 hp
Speed:	31 knots	29 knots
Endurance:	7,100 nm at 19 knots	8,525 nm at 19 knots
Fuel capacity:	6,108 metric tons	8,294 metric tons
Aircraft:	3 x Arado Ar 196	4 x Arado Ar 196
Crew:	1,900	2,065

source : http://www.kbismarck.com/