USS Obstructor (ACM-7)

USS Obstructor (ACM-7) was a Chimo-class minelayer in the United States Navy during World War II.

Built by the Marietta Manufacturing Company in Point Pleasant, West Virginia, as a U.S. Army mine planter, USAMP 1st Lt. William G. Sylvester (MP-5) was delivered in December 1942 to the U.S. Army Coast Artillery Corps, Mine Planter Service. She was named for the first coast artillery officer killed (at Hickam Field, Hawaii, on 7 December 1941) in action in World War II. The Sylvester's embarked crew was, in Army terminology, implemented in November 1942, designated the 12th Coast Artillery Mine Planter Battery stationed at Fort Miles, Delaware.

The ship was transferred to the Navy on 4 January 1945. It was renamed Obstructor on 19 January 1945, converted at the Charleston Navy Yard and commissioned on 1 April 1945 with Lt. Sammie Smith in command.

Pacific Theatre operations
Following shakedown in Chesapeake Bay, Obstructor, a minesweep gear and repair ship, loaded gear and other supplies at Norfolk, Virginia, and sailed on 11 June 1945 for the Panama Canal. Transiting the canal on 21 June, she proceeded up the coast to San Diego. There at the end of the war, she sailed for the Far East on 18 August. Steaming via the Marshalls and the Marianas, she arrived at Manila and reported for duty with MinRon 106 on 8 October. On 17 October she got underway for Haiphong, arriving and joining task unit TU 74.4 on 22 October. Assuming duties as flagship, MinRon 106, the same day, Obstructor served as a minecraft tender for that task unit as it operated off Haiphong harbor, the island of Hainan and off Chinese ports during the next six months.

Decommissioning
In early May 1946, she sailed east en route back to the United States. Arriving at San Francisco on 15 June, she was decommissioned and was transferred to the U.S. Coast Guard on 28 June and was struck from the Navy List on 19 July 1946.

U.S. Coast Guard service history
Transferred to the U.S. Coast Guard, the ship was commissioned on 1 February 1947 as Heather (WABL / WLB-331) and stationed at Mobile, Alabama, until 5 December 1949. Heather was transferred and began operations from San Pedro, California, on 6 December 1949 until decommissioning on 15 December 1967 and transfer to Seattle, Washington, on 12 April 1968.