commissioned on 25 February 1941. The made two battleship raids against Allied convoys in the Atlantic Ocean during early 1941. The battleships and conducted Operation Berlin between January and March 1941. During this raid they sailed from Germany, attacked Allied shipping and returned to occupied France. A second raid, Operation Rheinübung, was attempted in May and involved the battleship Bismarck and heavy cruiser Prinz Eugen. While the German ships destroyed the British battlecruiser HMS Hood on 24 May, Bismarck was crippled by Fairey Swordfish torpedo bombers from the British aircraft carrier and sank on 27 May after being bombarded by several British battleships from the Home Fleet. Admiral Sir John Tovey was the commander in chief of this fleet, and led it from the battleship during the battle. The loss of Bismarck left Tirpitz as Germany's only remaining full-sized battleship. At the time her crew were still being trained. After the German invasion of the Soviet Union on 22 June 1941 the Allies began sending convoys loaded with supplies through the Norwegian Sea and Arctic Ocean to ports in northern Russia. The Arctic convoys that were dispatched during 1941 and early 1942 were lightly opposed, with only a single Allied merchant ship and the destroyer being sunk by German submarines prior to March 1942. Harsh weather conditions, including extreme cold, heavy seas and gales, made air and naval operations in the area difficult for all of the combatants. In December 1941 the German military began transferring substantial naval and air forces to northern Norway, which they had occupied since early 1940. The forces sent to Norway were tasked with attacking the Arctic convoys as well as defending the area from an invasion. At this time the German dictator Adolf Hitler wrongly believed the Allies intended to invade Norway. On 12 January 1942 Hitler ordered Tirpitz to be transferred from Germany to Trondheim in Norway. The battleship and two escorting destroyers departed Wilhelmshaven in Germany on 14 January and arrived in Trondheim on 16 January. She was to form the main element of a powerful battle group once other German warships arrived in the area. Karl Topp commanded Tirpitz at this time. The Allies learned of Tirpitzs arrival at Trondheim on 17 January from Ultra intelligence obtained by decrypting intercepted German radio signals. British photo reconnaissance aircraft located the battleship there on 23 January, and regular sorties were flown over the