The Treaty of Versailles drastically limited the size of the postwar Kriegsmarine. Germany would not be allowed any dreadnought battleships. The Germans could keep pre-dreadnought vessels of 10000 tons or less, roughly the size of a heavy cruiser in most navies. Presented with a problem, the German engineers developed a novel solution. They designed the pocket battleships, warships of relatively small size (12000 tons or so), with relatively heavy armamanets (6 11″ guns) that were faster than any ship more powerful than they and more powerful than any ship faster. The pocket battleships were designed as commerce raiders, not as main line units.
Alas, the concept behind the pocket battleships went the way of all technology. The Royal Navy retained three of its battlecruisers, each of which would have no difficulty catching and destroying the German ships. More troubling, the French built Dunkerque and Strasbourg, a pair of battlecruisers that similarly would have meant doom for the German vessels.
In 1933, the new Nazi government was looking for a way to tweak the British and French. The Kriegsmarine realized that building additional pocket battleships would serve no compelling purpose. Accordingly, the navy developed plans for two new ships, MUCH larger than the pocket battleships. These ships became the battlecruisers Scharnhorst and Gneisenau, named after a pair of crack armored cruisers destroyed at the Battle of Falkland Islands. Scharnhorst displaced 33000 tons and carried 9 11″ guns, leftovers from cancelled pocket battleships. Plans to fit Scharnhorst with 6 15″ guns were never carried out. Scharnhorst could make 32 knots, superior to most of the ships of the Royal Navy.
Scharnhorst had an extremely active career. After a couple early raiding cruises, Scharnhorst and Gneisenau helped cover the German landings in Norway. They engaged, without much effect, the British battlecruiser Renown. A month later, the British aircraft carrier Glorious somehow blundered into Scharnhorst and Gneisenau. The German ships quickly destroyed the British carrier, although Scharnhorst took a torpedo hit. In early 1941, Scharnhorst and Gneisenau left Kiel for a very successful two month raiding cruise before pulling into the French naval base at Brest. The Kriegsmarine planned a massive naval operation for May 1941. Scharnhorst and Gneisenau would depart from Brest and lead the Royal Navy to the south. In the meantime, the newly commissioned Bismarck, accompanied by the cruiser Prinz Eugen, would enter the Atlantic through Denmark Straights and wreak havoc on Atlantic convoys. Bismarck, being a battleship, could deal with the older British battleships used to escort convoys. Unfortunately for the Germans, RAF attacks on Brest disabled the facilities and prevented Scharnhorst and Gneisenau from sortieing. Bismarck’s journey was not, erm, successful.
Scharnhorst remained at Brest for the rest of 1941, but increased RAF bombing attacks made the German naval presence untenable. The German ships could not sortie, and could not remain in Brest. The Germans developed a risky plan in which Scharnhorst, Gneisenau, Prinz Eugen, and six destroyers would dash up the English Channel, hopefully avoiding British surface ships, aircraft, and submarines, in an effort to make it to Wilhelmshaven. The plan worked beautifully, and the German fleet escaped with only minor damage. The dash was a great embarassment to the Admiralty and the Royal Air Force.
Scharnhorst remained at Kiel for most of 1942. In early 1943, she proceeded to Norway with Prinz Eugen (Gneisenau had been badly damaged by an RAF attack on Kiel, and would not be returned to service). While in Norway, Scharnhorst operated as part of a “fleet in being” with Prinz Eugen, Tirpitz (the sister of Bismarck), and other ships. These vessels threatened British convoys to Russia, inducing the convoys to occasionally disperse (making the easy prey for U-boats), and forcing the Royal Navy to keep assets in the area.
On Christmas, 1943, Scharnhorst departed Norway in an attempt to catch a British convoy. Unfortunately for the Germans, the Royal Navy received intelligence of the German movements, and dispatched Duke of York with several cruisers and destroyers to intercept. Duke of York was a fast battleship, more heavily armed and armored than Scharnhorst. The German battlecruiser withstood several hits before losing speed, at which point the British cruisers and destroyers closed to make a torpedo attack on Scharnhorst. The ship capsized and sank at 7:45pm on December 26. 36 men from the crew of 1968 were rescued.