A RAF Coastal Command Catalina, piloted by Ensign Leonard B. Smith of the U.S. Navy and flying out of Castle Archdale Flying boat base, Lower Lough Erne, Northern Ireland, located on 26 May 1941, some 690 nautical miles northwest of Brest, the German battleship Bismarck, which was attempting to evade Royal Navy forces as she sought to join other Kriegsmarine forces in Brest.