 Complete the following phrase:  At the start of World War II, Sturgeon conducted patrols in the North Sea. On 6 September, she was mistakenly bombed by British aircraft. On her second patrol, she fired three torpedoes at an unidentified submarine, which was in fact her sister ship , but the torpedoes missed. On her third patrol, she missed the German U-boat and was damaged after hitting the bottom, requiring repairs. On 20 November, she sank the German armed trawler with torpedoes. The sinking was the first successful attack by a British submarine of the war, and was a morale boost for British submariners. During her next patrols in the North Sea, Sturgeon sighted and sank several ships, including the German troop transport Pionier and the Danish merchants SS Sigrun and SS Delfinus. Afterwards, Sturgeon patrolled in the Bay of Biscay, acted as a beacon during Operation Torch, then, after being again damaged by Allied aircraft, escorted the 