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NavSource Online: Mine Warfare Vessel Photo Archive

USCGC Heather (WLB 331)
ex-USCGC Heather (WAGL 331)
ex-USS Obstructor (ACM 7)
ex-USAMP 1st Lieutenant William G. Sylvester

Obstructor served the US Army, Navy and Coast Guard

Chimo Class Auxiliary Minelayer:

  • Laid down in 1941 for the U.S. Army Coast Artillery Corps, Mine Planter Service as USAMP 1st Lieutenant William G. Sylvester at Marietta Manufacturing Co., Point Pleasant, WV
  • Launched in 1942
  • Transferred to the Navy 4 January 1945 and converted to an Auxiliary Minelayer at Charleston Navy Yard
  • Commissioned USS Obstructor (ACM 7), 1 April 1945
  • Decommissioned 28 June 1946 and transferred to the Coast Guard
  • Struck from the Naval Register 19 July 1946
  • Commissioned USCGC Heather (WAGL 331), 1 February 1947
  • Reclassified WLB-331 in 1965
  • Decommissioned 15 December 1967
  • Transferred to Seattle, WA 12 April 1968
  • Fate unknown.


  • Displacement 1,300 t.
  • Length 188' 2"
  • Beam 37'
  • Draft 12' 6"
  • Speed 12.5 kts.
  • Complement 69
  • Armament: One 40mm gun mount, and four 20mm mounts
  • Propulsion: Two Combustion Engineering header type boilers, two 1,200shp Skinner Unaflow reciprocating engines, two shafts.
    Click on thumbnail
    for full size image
    Size Image Description Source
    USAMP 1st Lieutenant William G. Sylvester
    Obstructor 17k William Sylvester posed for Bakersfield High School yearbook, Class of 1934
    Photo courtesy of Ken Hooper, Bakersfield, CA
    Tommy Trampp
    Photos added 17 September 2021
    Obstructor 106k The U.S. Government chose Decoration Day in 1949 to unveil a plaque and the new electronics building at Fort Bliss, Texas to the memory of Lt. Sylvester. His mother and stepfather were present for the ceremony
    Photo courtesy of John Hamilton, Fort Bliss, Texas
    USS Obstructor (ACM 7)
    Obstructor 177k Anchored off Hong Kong, in the fall of 1945
    Courtesy of Lieutenant Commander John J. Heard, USNR, (Ret), 1978
    Naval History and Heritage Command photo NH 86269
    Mike Green
    Obstructor 49k 15 June 1946
    Arriving back at San Francisco, CA
    Mel Haas MM/3c
    Former crew member
    USCGC Heather (WAGL 331)
    Obstructor 60k Robert Hurst
    USCGC Heather (WLB 331)
    Obstructor 50k c. 1967 Robert Hurst

    Commanding Officers
    01LCDR Sammie Smith, USNR1 April 1945 - 17 October 1945
    02LT John J. Heard, USNR17 October 1945 - 16 December 1945
    03LTJG Richard Ellis Nippes, USNR16 December 1945 - 8 January 1946
    04LT Joseph S. Slocum, USNR8 January 1946 - 5 March 1946
    05LTJG Eugene Harter Chittenden, USN5 March 1946 - 28 June 1946
    Courtesy of Wolfgang Hechler and Ron Reeves

    View the Obstructor (ACM 7)
    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 Minelayer (ACM) Photo Index Back to the U.S. Army Mine Planter Photo Index

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