USS Implicit (AM-455)

For other ships with the same name, see USS Implicit.

USS Implicit (AM-455/MSO-455) was an Agile-class minesweeper acquired by the U.S. Navy for the task of removing mines that had been placed in the water to prevent the safe passage of ships.

History
United States
Name	USS Implicit (MSO-455)
Builder	Wilmington Boat Works, Wilmington, California
Laid down	29 October 1952
Launched	1 August 1953
Commissioned	10 March 1954
Decommissioned	30 September 1994
Reclassified	MSO-455, 7 February 1955
Stricken	20 November 1994
Homeport	Long Beach, California
Fate	transferred to the Republic of China, 30 September 1994
Republic of China
Name	ROCS Yung Yang (MSO-1306)
Acquired	30 September 1994
Decommissioned	1 July 2025
General characteristics
Class & type	Agile class minesweeper
Displacement	620 tons
Length	172 ft (52.43 m)
Beam	36 ft (10.97 m)
Draught	10 ft (3.05 m)
Propulsion	Four Packard ID1700 diesel engines, two shafts, two controllable pitch propellers
Speed	16 knots
Complement	72
Armament	one 40 mm mount

Implicit was launched by Wilmington Boat Works, Wilmington, California 1 August 1953; sponsored by Mrs. Landon Horton, and commissioned 10 March 1954.

West Coast deployment

One of a class of new minesweepers constructed entirely of nonmagnetic materials, Implicit conducted shakedown training in California waters during mid-1954. She then began an operational pattern which was to continue for three years: minesweeping exercises, fleet maneuvers, and training cruises in the California-Mexico area. The ship then got underway from her home port, Long Beach, California, 7 August 1957 to join the U.S. 7th Fleet in the strategic Far East. During this deployment, Implicit operated with Japanese ships, Nationalist Chinese minesweepers, and with regular units of the U.S. 7th Fleet on their daily mission of maintaining peace and security in the area. She returned to Long Beach 1 March 1958.

Second Far East cruise

Training and readiness exercises out of Long Beach occupied the minesweeper until her second cruise to the Far East. She steamed out of Long Beach 8 January 1960 and during six months in the western Pacific Ocean took part in mine warfare exercises with 7th Fleet ships in the Philippines and off Okinawa. Implicit arrived Long Beach after this cruise 17 July 1960.

Participating in joint U.S.-Canadian exercises

Training operations and mine countermeasures drill were carried out until August 1961, when the veteran minecraft took part in joint American-Canadian mine-sweeping exercises off British Columbia.

Supporting Vietnam operations

Returning to Long Beach, the ship prepared for another Far Eastern deployment, this time in support of the American advisory effort in South Vietnam. Sailing 2 January 1962 for this embattled country, Implicit first participated in SEATO maneuvers and then moved to various ports in South Vietnam to assist in training officers and men. She returned to Long Beach from South Vietnam 17 August 1962.

Joint exercises with the Republic of China Navy

Implicit resumed a schedule of underway training and fleet exercises out of Long Beach until her next deployment, sailing with her division 3 January 1964. Stopping at Guam and Midway Island en route, she arrived off Taiwan for mine-warfare exercises in March. In May she returned to the Formosa Strait for a second operation, in which the ship acted under a Chinese Nationalist division commander in a demonstration of cooperation and smooth combined operations. Following her second SEATO exercise in the Pacific, Implicit resumed to Long Beach 28 July 1964 for a yard overhaul and readiness tactics and training along the coast of California.

Supporting Operation Market Time

Implicit in 1954.

Implicit departed Long Beach 21 September 1965 for the Far East. A unit of Mine Division 91, she joined the "Market Time Patrol" along Vietnam's 1,000-mile coastline to intercept Vietcong men and supplies trying to infiltrate into South Vietnam. Once she was fired on by Vietcong while cruising close to shore and retaliated with her 40mm. and other machineguns.

After a 2-week stopover, Implicit departed Kaohsiung, Taiwan, 14 January to continue her "Market Time" patrols into late 1966. By 15 March she had boarded more than 1,000 junks and sampans for inspection. On 22 and 23 March, the minesweeper fired nearly 700 rounds of 40mm. ammunition supporting small South Vietnamese naval craft under fire from enemy shore batteries. On 28 June Implicit got underway with a mine division for Long Beach, California, via Guam, Kwajalein, and Pearl Harbor arriving Long Beach, 2 August From 13 to 20 September she participated in minesweeping Operation Eager Angler off Santa; Rosa Island. Implicit joined a carrier task unit for Operation COMPTUEX through December and then continued training operations off Long Beach into 1967.

Decommissioning

Yung Yang(MSO-1306)

Implicit was decommissioned 30 September 1994 and handed over to Republic of China Navy among 3 other mine sweepers. She served in the ROC Navy until July 1st, 2025, when she was decommissioned.^[1][2][3]

She was the last wooden ship in the Navy that carried a full inspection cycle.