High Quality Content by WIKIPEDIA articles! HMS Black Swan (Pennant Numbers L57, U57, later F57), named after the Black Swan, was the name ship of the Black Swan-class of sloops of the British Royal Navy. This class was admired for its sea-going qualities. She was laid down by Yarrow Shipbuilders on 20 June 1938, launched on 7 July 1939, and commissioned on 27 January 1940.