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NavSource Online: Mine Warfare Vessel Photo Archive


MSO-486 was built for Portugal.

AM-478 Class Minesweeper:

  • Laid down 16 May 1953 as AM-486 by the Burger Boat Co., Manitowoc, WI
  • Launched 19 November 1953
  • Sponsored by Mrs. J. G. Barver
  • Reclassified by U. S. Navy as an Ocean Minesweeper, MSO-486, 7 February 1955
  • Completed 15 July 1955
  • Transferred to Portugal 15 August 1955 and named NRP Graciosa (M 417)
  • Decommissioned in April 1973 and scrapped at Southend-on-Sea, United Kingdom.


  • Displacement 665 t.
  • Length 172'
  • Beam 35'
  • Draft 10'
  • Speed 13.5 kts.
  • Complement 39
  • Armament: One 40mm mount and two .50 cal. machine guns
  • Propulsion: Two 800shp General Motors diesel engines, two shafts.
    Click on thumbnail
    for full size image
    Size Image Description Source
    MSO-478 134k c. 1970
    Portuguese Navy photo
    Robert Hurst
    Blaricum 57k 7 August 1979
    Southend-on-Sea, United Kingdom
    Being scrapped, left to right, the Graciosa, the Dutch minesweeper Blaricum (M 853), ex-MSC-112 and the Italian minesweeper Arsella (M 5451), ex-MSI-59

    There is no DANFS history available for MSO-486
    Additional Resources and Web Sites of Interest
    102 Minesweepers (MSO) Oceangoing Minesweepers
    Naval Minewarfare Association
    Association of Minemen
    Back to the Main Photo Index Back to the Mine Warfare Ship Photo Index Back to the Ocean Minesweeper (MSO) Photo Index

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    This page created and maintained by Joseph M. Radigan
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