HMS Calgarian was an armed merchant cruiser of the Royal Navy. She was sunk by the U-boat off Rathlin Island, Northern Ireland on 1 March 1918. The initial strike did not sink her and the crew managed to contain the damage. The U-boat torpedoed her again, despite the protection of other ships. She was hit by 4 torpedoes and quickly sank with the loss of two officers and 47 ratings. SS Calgarian was originally built for the Allan Line, making her maiden voyage from Liverpool to Canada on 8 May 1914. Her sister ship was the Alsatian.