Launching of Seydlitz
|Namesake||Friedrich Wilhelm von Seydlitz|
|Builder||Deutsche Schiff- und Maschinenbau, Bremen|
|Laid down||29 December 1936|
|Launched||19 January 1939|
|Fate||Scuttled incomplete, 29 January 1945|
|General characteristics (as cruiser)|
|Class and type||Admiral Hipper-class cruiser|
|Length||210 m (689 ft 0 in) overall|
|Beam||21.80 m (71 ft 6 in)|
|Draft||Full load: 7.90 m (25.9 ft)|
|Speed||32 knots (59 km/h; 37 mph)|
|Aircraft carried||3 aircraft|
|Aviation facilities||1 catapult|
|General characteristics (as aircraft carrier)|
|Class and type||none|
|Length||216 m (708 ft 8 in) overall|
|Draft||Full load: 6.65 m (21.8 ft)|
|Aircraft carried||20 aircraft|
Seydlitz was a heavy cruiser of Nazi Germany's Kriegsmarine, fourth in the Admiral Hipper class, but was never completed. The ship was laid down in December 1936 and launched in January 1939, but the outbreak of World War II slowed her construction and fitting-out work was finally stopped in the summer of 1940 when she was approximately 95 percent complete. The unfinished ship remained pier-side in the shipyard until March 1942, when the Kriegsmarine decided to pursue aircraft carriers over surface combatants. Seydlitz was among the vessels chosen for conversion into auxiliary aircraft carriers.
Renamed Weser, the ship was to have had a complement of ten Bf 109 fighters and ten Ju 87 divebombers. Work was not completed, however, and the incomplete vessel was towed to Königsberg where she was eventually scuttled. The ship was seized by the advancing Soviet Army and was briefly considered for cannibalization for spare parts to complete her sistership Lützow for the Soviet Navy. This plan was also abandoned, and the ship was broken up for scrap.
The Admiral Hipper class of heavy cruisers was ordered in the context of German naval rearmament after the Nazi Party came to power in 1933 and repudiated the disarmament clauses of the Treaty of Versailles. In 1935, Germany signed the Anglo–German Naval Agreement with Great Britain, which provided a legal basis for German naval rearmament; the treaty specified that Germany would be able to build five 10,000-long-ton (10,000 t) "treaty cruisers". The Admiral Hippers were nominally within the 10,000-ton limit, though they significantly exceeded the figure.
Seydlitz was 210 meters (690 ft) long overall and had a beam of 21.80 m (71.5 ft) and a maximum draft of 7.90 m (25.9 ft). The ship had a design displacement of 17,600 t (17,300 long tons; 19,400 short tons) and a full load displacement of 19,800 long tons (20,100 t). Seydlitz was powered by three sets of geared steam turbines, which were supplied with steam by twelve ultra-high pressure oil-fired boilers. The ship's top speed was 32 knots (59 km/h; 37 mph), at 132,000 shaft horsepower (98,000 kW). As designed, her standard complement consisted of 42 officers and 1,340 enlisted men.
Seydlitz's primary armament was eight 20.3 cm (8.0 in) SK L/60 guns mounted in four twin gun turrets, placed in superfiring pairs forward and aft.[a] Her anti-aircraft battery consisted of twelve 10.5 cm (4.1 in) L/65 guns, twelve 3.7 cm (1.5 in) guns, and eight 2 cm (0.79 in) guns. The ship also carried a pair of triple 53.3 cm (21.0 in) torpedo launchers abreast of the rear superstructure. The ship was equipped with three Arado Ar 196 seaplanes and one catapult. Seydlitz's armored belt was 70 to 80 mm (2.8 to 3.1 in) thick; her upper deck was 12 to 30 mm (0.47 to 1.18 in) thick while the main armored deck was 20 to 50 mm (0.79 to 1.97 in) thick. The main battery turrets had 105 mm (4.1 in) thick faces and 70 mm thick sides.
Seydlitz was ordered by the Kriegsmarine from the Deschimag shipyard in Bremen. Seydlitz was originally designed as a light cruiser version of the Admiral Hipper-class heavy cruisers, armed with twelve 15 cm (5.9 in) guns instead of the Admiral Hipper's eight 20.3 cm (8.0 in) guns. The Kriegsmarine decided, however, to complete the ship identically to Admiral Hipper on 14 November 1936. Her keel was laid on 29 December 1936, under construction number 940. The ship was launched on 19 January 1939, but after the outbreak of World War II in September 1939, work was halted when the ship was approximately 95 percent complete.
Following the loss of the battleship Bismarck in May 1941, during which British aircraft carriers proved instrumental, and the near torpedoing of her sistership Tirpitz in March 1942, the Kriegsmarine became convinced of the necessity of acquiring aircraft carriers. Work on the purpose-built carrier Graf Zeppelin, which had been halted in April 1940, was resumed in March 1942. The Kriegsmarine also decided to convert a number of vessels into auxiliary aircraft carriers. Seydlitz was among the ships selected for conversion, along with several passenger liners.
At the same time as construction of Graf Zeppelin resumed, conversion work began on Seydlitz. The majority of the superstructure was cut away, with the exception of the funnel, to prepare for the installation of a flight deck and an aircraft hangar. In total, approximately 2,400 t (2,400 long tons; 2,600 short tons) of material from the ship was removed. The flight deck was to have been 200 m (660 ft) long and 30 m (98 ft) wide. The hangar was 137.50 m (451.1 ft) long and 17 m (56 ft) wide forward and 12 m (39 ft) wide amidships and aft. Her armament was reduced to an anti-aircraft battery of ten 10.5 cm L/65 guns in twin mounts, two forward of the conning tower and three aft, ten 3.7 cm guns in dual mounts, and twenty-four 2 cm guns in quadruple mounts.
Seydlitz's air complement was to have consisted of ten Bf 109 fighters and ten Ju 87 Stuka divebombers. The Bf 109 fighters were a navalized version of the "E" model, designated as Bf 109T. Their wings were longer than the land-based model to allow for shorter take-off. The Ju 87 type selected was to have been the "E" variant, which was a navalized version of the Ju 87D, and were modified for catapult launches and were equipped with arresting gear.
The ship was renamed Weser, but work was ceased in June 1943, before the conversion was completed. The unfinished vessel was then transferred to Königsberg, where she remained for the rest of the war. On 29 January 1945, the ship was scuttled before the advancing Soviet Red Army could seize her. The Soviet Navy nevertheless considered using the wreck for parts to complete the cruiser Lützow, a sister-ship of Seydlitz the Soviets had purchased unfinished before the outbreak of war. This was not carried out, however, and the ship was broken up for scrap.