HMS Rawalpindi was a British armed merchant cruiser that was sunk in a surface action against the German battleships Scharnhorst and Gneisenau during the first months of the Second World War. Her captain was Edward Kennedy.
Scale model of HMS Rawalpindi
An armed merchantman is a merchant ship equipped with guns, usually for defensive purposes, either by design or after the fact. In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in long distance and high value trade.
HMS Alcantara and SMS Greif dueling at close range during the action of 29 February 1916
RMS Carmania sinking SMS Cap Trafalgar near the Brazilian islands of Trindade, 14 September 1914
Kormoran in 1940. During a single ship action on 19 November 1941, off the coast of Western Australia the German auxiliary cruiser Kormoran sank HMAS Sydney before being scuttled.