SM U-56 was one of the 329 submarines serving in the Imperial German Navy in World War I.U-56 was engaged in the naval warfare and took part in the First Battle of the Atlantic. On 2 November 1916, U-56 was attacked by gunfire from the Imperial Russian Navy destroyer Grozovoi off Khorne Island, Norway (near Vardø). U-56 survived this attack. U-56 dropped off the crew of the Norwegian merchant ship Ivanhoe ashore at 07:45 on 3 November 1916 at . The Norwegian sailors were aboard the ship during the action of the previous day and their description matches with the Russian account.