On 20 December 1943, "Scharnhorst" was ordered to intercept the next convoy to the Soviet Union, Convoy JW 55B. The ship was to operate only with five destroyers; "Tirpitz" had been damaged in a British raid in September, and "Lützow" was away for periodic repairs. On 25 December, the location of the convoy was ascertained, and at 19:00 the ship left port, under the command of Rear-Admiral Erich Bey. The British fleet had a significant advantage: they were able to decrypt German naval codes, and were aware of Bey's intentions. The cruisers , , and were positioned to block "Scharnhorst". Admiral Bruce Fraser, aboard the battleship , was some 270 miles away, and steaming to cut off "Scharnhorst" after she was engaged by the three cruisers. "Belfast" picked up "Scharnhorst" on radar at 08:40; forty minutes later lookouts on "Sheffield" spotted the ship, at a distance of . Shortly thereafter, "Belfast" fired star shells to illuminate the target, and "Norfolk" opened fire with her 20.3 cm (8 in) guns; in the span of 20 minutes, she hit "Scharnhorst" twice. The second hit destroyed "Scharnhorst"'s forward Seetakt radar.