(ATA-198: dp. 534; l. 143'; b. 34'; s. 13 k.; cpl. 48; a. 13", 2 20mm.; cl. Maricopa)
Originally designated as ATR-125, she was redesignated ATA-198 on 15 May 1944; launched 17 January 1945 by Levingston Shipbuilding Co., Orange, Tex.; and commissioned 19 March, Lt. J. L. Bean in command.
Departing Galveston 18 April, ATA-198 steamed via the Panama Canal and San Francisco for duty in the Pacific. She reached Pearl Harbor 1 June, then continued 7 June via Eniwetok and Ulithi towing Pegasus (IX-222) to the Philippines. Arriving Leyte Gulf 18 July, she departed the 21st and reached Pearl Harbor via Kwajalein 7 August. From 9 August to 31 October she made two towing runs to San Francisco, and then resumed harbor and barge towing duty out of Pearl Harbor. For more than 3 years she made periodic towing runs to Wake Island; to various islands in the Hawaiian chain, including Maui and Midway; and to the West Coast.
Renamed Keosanqua 16 July 1948, she departed Pearl Harbor 7 December for Long Beach, where she arrived 22 December. Proceeding to San Diego 3 January 1949, she commenced target towing duty with the Fleet Sonar School and provided harbor and coastal towing services between San Diego and Long Beach. On 19 June 1951, while the United States fought to protect South Korea from Communist aggression, she departed San Diego for a 10-month deployment in the western Pacific.
Operating primarily out of Sasebo, Japan, Keosanqua provided tug service along the coast of Korea from Makpo to Inchon. Departing Sasebo 25 March, she steamed via Pearl Harbor to San Diego, arriving 19 April.
On two subsequent deployments (26 January-30 September 1953 and 7 February-2 October 1955) Keosanqua served with the mighty 7th Fleet in the Far East, providing harbor tug and target towing services out of Sasebo and Yokosuka. After returning from the western Pacific in 1955, she continued operations out of San Diego until 25 May 1956 when she decommissioned and entered the Pacific Reserve Fleet. Her name was struck from the Navy List 1 May 1961. She was transferred to the Republic of Korea and commissioned ROKS Yong Mun (ATA-2) on 1 February 1962.
Keosanqua received three battle stars for Korean War service.