 The outbreak of the Second World War saw "M85" supporting the German invasion of Poland in September 1939, and she was sunk by a Polish mine on 1 October 1939 in one of the last acts of the Polish campaign.The M1916 Type minesweeper was an improved and slightly enlarged derivative of the M1914 and M1915 Type minesweepers which Germany had built since 1914.They were fleet minesweepers, seaworthy enough to operate in the open sea, and proved to be successful and reliable in service.