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NavSource Online: Mine Warfare Vessel Photo Archive

HM BYMS-2021
ex-HM J-821

BYMS-21 was built for Great Britain

BYMS-1 Class Motor Minesweeper:

  • Laid down 11 August 1941 as BYMS-21 by the Seattle Shipbuilding and Drydock Co., Seattle, WA
  • Launched 28 February 1942
  • Completed 31 July 1942
  • Transferred to Great Britain 3 August 1942 and reclassified HM J-821
  • Reclassified HM BYMS-2021
  • Transferred to the State Department, Foreign Liquidation Commission in August 1947
  • Returned to U.S. custody 1 September 1947 and sold
  • Fate unknown.


  • Displacement 270 t.
  • Length 136'
  • Beam 24' 6"
  • Draft 8'
  • Speed 15 kts.
  • Complement 32
  • Armament: One 3"/50 dual purpose gun mount, two 20mm mounts and two depth charge projectors
  • Propulsion: Two 880bhp General Motors diesel engines, Snow and Knobstedt single reduction gear, two shafts.
    Click on thumbnail
    for full size image
    Size Image Description Source
    BYMS-21 77k Freetown Harbor, Sierra Leone Robert Hurst
    BYMS-21 & YMS-161 122k Moored outboard of BYMS-2161, as part of a flotilla of British Yard Minesweepers tied up on the quayside in Copenhagen, Denmark harbour. They were the first British warships to enter that harbour at the close of hostilities at the end of WW II
    Photos from the collection of Able Seaman Appleford
    Ian Appleford
    BYMS-21 & YMS-161 108k

    There is no DANFS history available for BYMS-21
    Additional Resources and Web Sites of Interest
    Naval Minewarfare Association
    Association of Minemen
    Back To The Main Photo Index Back To the Mine Warfare Ship Photo Index Back to the British Motor Minesweeper (BYMS) Photo Index

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    This page created and maintained by Joseph M. Radigan
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