The Tribal class was originally conceived as a series of destroyers with greater emphasis on guns over torpedoes in response to new designs by other countries. HMS Cossack participated in the second battle of Narvik and in the legendary Hunt for Bismarck, during which she conducted a series of torpedo attacks on the famous German battleship. In 1941, HMS Cossack slipped beneath the waves after being struck by torpedoes from German submarine U-563. Among the rescued crew members was the ship's cat Oscar, which had previously been rescued from Bismarck! The cat gained the nickname "Unsinkable Sam" and would later also survive the sinking of his next ship, aircraft carrier Ark Royal.