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NavSource Online: Mine Warfare Vessel Photo Archive


Courtesy of Arie van Mazijk

Call sign:
Papa - Alpha - Xray - Tango

AM-484 was built for the Netherlands

AM-480 Class Fleet Minesweeper:

  • Laid down 27 February 1952 as AM-484 by Peterson Builders Inc., Sturgeon Bay, WI
  • Launched 2 May 1953
  • Completed 12 August 1955
  • Transferred to the Netherlands and commissioned HRNLMS Onvermoeid (M 887), 23 September 1954
  • Reclassified by U. S. Navy as an Ocean Minesweeper, MSO-484, 7 February 1955
  • Reclassified A-857 in August 1965
  • Placed out of service 1 October 1971
  • Struck from the Naval Register 15 June 1972
  • Scrapped 8 January 1975 by Ross and Sons of Girvan, Ayrshire, United Kingdom.


  • Displacement 750 t.
  • Length 171'
  • Beam 35'
  • Draft 10' 4"
  • Speed 15 kts.
  • Complement 39
  • Armament: One 40mm mount and two .50 cal. machine guns
  • Propulsion: Two 800shp General Motors diesel enginess, two shafts.
    Click on thumbnail
    for full size image
    Size Image Description Source
    AM-484 55k Minesweeper hulls AM-483, 484, 485 for the Netherlands in the background. In the foreground is the last American-made side-wheeler still afloat in the U.S. and used as a floating warehouse. Restored and now serves as a museum in Sandusky, Ohio
    Photo courtesy Peterson Builders
    Mercuur Museum Website
    HRNLMS Onvermoeid (M 887)
    MSO-484 64k 30 April 1955
    Ponta Delgada, Azores
    Brouwershaven (M 858), ex-MSC-150, Onvermoeid and Onverdroten (M 889), ex-MSO-485 in dress ship for Queen's Day still wearing their U.S. Navy hull numbers
    Arie van Mazijk
    HRNLMS Onvermoeid (A 857)
    MSO-484 168k HRNLMS Vos (F 820), ex-PCE-1606, HRNLMS Panter (F 821), ex-PCE-1608 and Onvermoeid passing the light cruiser de Ruyter (C 801) to port Pieter Bakels
    MSO-484 77k . Arie van Mazijk
    MSO-484 98k
    MSO-484 96k
    MSO-484 395k Leading a squadron of seven Adjutant/Beemster Class Coastal Minesweepers, with HRNLMS Borne (M 850) to starboard and HRNLMS Breukelen (M 852) to port
    MSO-484 386k Leading a squadron of five Adjutant/Beemster Class Coastal Minesweepers
    MSO-484 71k .
    MSO-485 107k Undated post card showing Onvermoeid, Onbevreesd (A 855) and Onverdroten (A 859) laid up in the Reserve Fleet

    There is no DANFS history available for MSO-484
    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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