A merchant name retained. Mercer (APB‑39) is named for counties in Illinois, Kentucky, Missouri, New Jersey, North Dakota, Ohio, Pennsylvania, and West Virginia.
(APB‑39: dp. 4,080; l. 328'; b. 50'; dr. 11'2"; s. 10 k.; cpl. 141; trp. 1,226; a. 8 40mm., 8 20mm.; cl. Benewah)
The second Mercer (APB‑39), originally APL‑39, was reclassified APB‑39, 7 August 1944; laid down 24 August 1944 by Boston Navy Yard; launched as APB‑39, 17 November 1144: sponsored by Mrs. Lillian Gaudette; named Mercer 14 March 1945; and commissioned 19 September 1945, Lt. Comdr. Edward E. Vezey, Jr., USNR, in command.
Mercer, a barracks ship built on an LST hull, commenced her career of berthing and messing large numbers of naval personnel at New York 7 November 1915. Transferred to the Inactive Fleet in January 1946, she remained at New York until 9 September, when she got underway for Orange, Tex., and duty there until the spring of 1947. She then headed for Green Cove Springs, Fla., where she decommissioned 18 June 1947, but remained in service with the Florida Group, Atlantic Reserve Fleet. She recommissioned 12 October 1951 and after brief overhaul sailed for Norfolk, Va., en route to Naples, Italy, where she served as receiving ship until 1 July 1952.
Returning to the United States 21 July, she underwent overhaul and reported to Davisville, R.I., for duty as barracks ship for Mobile Construction Battalions. On such duty into late 1955, Mercer was thrice deployed to Argentia, Newfoundland: 19 March to 3 October 1953, 14 March to 18 October 1954, and 27 February to 25 July 1955. Her Seabee duty was interrupted when she sailed to Washington, D.C., to berth midshipmen of the U.S. Merchant Marine Academy taking part in President Dwight Eisenhower’s Inaugural Parade in 1953.
Upon returning from her 1955 Argentia deployment, Mercer sailed to New York for preinactivation overhaul, and 7 November sailed for Green Cove Springs where she decommissioned 17 February 1956 and once again entered the Reserve Fleet. She was ordered reactivated 11 years later and taken to Long Beach for modernization. She recommissioned 11 May 1968 and on 2 June reported for duty with the Amphibious Force, Pacific Fleet, at San Diego. Within the month she was en route to her ultimate assignment, the Republic of Vietnam. Arriving at Vung Tau 31 July, into 1969 she has supported mobile naval units fighting Vietcong and North Vietnamese forces operating in South Vietnam.