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NavSource Online: Mine Warfare Vessel Photo Archive

Hummer (MSC[O] 20)

Call sign:
November - Charlie - Zulu - Delta

Hummer served the Navies of the United States and Japan.

YMS-1 Class Auxiliary Motor Minesweeper:

  • Laid down 11 December 1942 by Weaver Shipyards, Orange, TX
  • Launched 23 December 1943
  • Completed and commissioned USS YMS-372, 28 March 1944
  • Decommissioned 23 June 1946 at San Diego, CA
    Naval Vessel Register of 1 January 1949 lists plan for decommissioning and placing in reserve as February 1947
  • Named Hummer and reclassified as a Motor Minesweeper, AMS-20, 18 February 1947
  • Recommissioned 3 November 1950
  • Decommissioned 13 November 1953 at Long Beach, CA
  • Reclassified as a Coastal Minesweeper (Old), MSC(O)-20, 7 February 1955
  • Struck from the Naval Register 12 February 1959
  • Transferred to Japan 29 January 1959 and renamed Moroshima (MSC 663)
  • Fate unknown.


  • Displacement 270 t.
  • Length 136'
  • Beam 22' 9"
  • Draft 6' 3"
  • Speed 14.5 kts.
  • Complement 50
  • Armament: One 3"/50 dual purpose mount and two 20mm mounts
  • Propulsion: Two 880bhp General Motors 8-268A diesel engines, Snow and Knobstedt single reduction gear, two shafts.
    Click on thumbnail
    for full size image
    Size Image Description Source
    USS YMS-372
    YMS-372 121k Photo by Michael Pasterik EM1/c
    Crew member 1943 - 1945
    John S. Pasterik
    USS Hummer (AMS 20)
    YMS-372 118k Tommy Trampp
    JDS Moroshima (MSC 663)
    YMS-372 88k c. 1961
    Photo from the 1967/1968 edition of Jane's Fighting Ships
    Mike Green

    Commanding Officers
    01LTJG William Dempsey Randell, USN1950 - June 1952
    02LTJG Thomas Benton Parks, USNJune 1952 - 1953
    Courtesy Wolfgang Hechler and Ron Reeves

    View the Hummer (MSC[O] 20)
    DANFS history entry located on the Haze Gray & Underway website
    Back To The Main Photo Index Back To the Mine Warfare Ship Photo Index Back to the Auxiliary Motor Minesweeper (YMS) Photo Index Back to the Motor Minesweeper (AMS) Photo Index Back to the Coastal Minesweeper (MSC) Photo Index

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    This page created and maintained by Joseph M. Radigan
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