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USS IMPERVIOUS (MSO-449) - an Aggressive class minesweeper

In Commission 1954 to 1991

MSO-449 Deployments - Major Events

Add a MSO-449 Shellback Initiation Add a MSO-449 Deployment - Major Event
Month Year to Month Year Deployment / Event
NOV 1951 - Keel Date: 18 NOV 1951
at Martinolich Shipbuilding Co. San Diego CA
AUG 1952 - Launch Date: 29 AUG 1952
JUL 1954 - Commissioned: 15 JUL 1954
SEP 1964 - SEP 1964 West Pac-Viet Nam
APR 1966 - SEP 1966 West Pac-Viet Nam
APR 1966 - SEP 1966 West Pac-Viet Nam
JAN 1971 - DEC 1972 West Pac-Viet Nam
JAN 1972 - DEC 1972 West Pac-Viet Nam
FEB 1973 - JUL 1973 Operation Endsweep - Sweeping harbors in North Vietnam
FEB 1973 - JUL 1973 West Pac-Viet Nam
MAR 1974 - JUN 1974 Change of Homeport from Guam to Mayport FL
APR 1974 - APR 1974 Panama Canal
JUN 1974 - JUN 1974 Entered Reserve Trainer Status
JAN 1991 - JUN 1991 Desert Storm
DEC 1991 - Decommissioned: 12 DEC 1991

MSO-449 General Specifications

Class: Aggressive class minesweeper

Complement: 74 Officers and Enlisted

Displacement: 620 tons

Length: 172 feet

Beam: 36 feet

Draft: 10 feet

Final Disposition: Scrapped 4 December 2000


Impervious (AM-449) was launched by Martinolich Shipbuilding Co., San Diego, Calif., 29 August 1952 ; sponsored by Miss Mary Lin Moore; and commissioned 15 July 1954, Lt. Comdr. A. T. Ford in command.

Following shakedown and mine warfare training off the California coast, Impervious was reclassified MSO-449 on 7 February 1955. She sailed 1 July with her division for duty in the Far East with the 7th Fleet, arriving Sasebo via Pearl Harbor 5 August. During this deployment, she operated with ships of the Republic of Korea Navy and visited Taiwan before returning to her home port, Long Beach, 15 February 1956. During the next two years she operated out of Long Beach.

Impervious sailed for her second 7th Fleet deployment 3 January 1958, and during the next 6 months trained in Japanese waters. She also helped train Nationalist Chinese crews during April and May, preparing them to help to preserve the freedom and independence of Taiwan. The minesweeper returned to Long Beach 15 July 1958, and during September took part in a giant amphibious exercise off Camp Pendelton, Calif.

In April 1959 Impervious interrupted her regular training schedule to take part in a joint mine warfare exercise with Canadian ships, and spent the rest of the year on training exercises in California waters. In early 1960 the ship prepared for another deployment to the Far Bast, sailing 3 May for Japan. During August she participated in maneuvers with Korean and Nationalist Chinese ships, and in October Impervious operated with units of the Philippine Navy in similar operations off Corregidor. She sailed via Guam and Pearl Harbor to Long Beach, arriving 16 November.

The ship spent 1961 and early 1962 on important readiness operations, visiting several West Coast ports, and sailed again for 7th Fleet duty 7 April 1962. After training in the Philippines the minesweeper spent part of July on patrol with Vietnamese Naval units off Danang, and the Navy supported the South Vietnamese people in their fight for freedom. She visited Hong Kong and Yokosuka before arriving Pearl Harbor 8 September 1962. During October and November, Impervious took part in atomic tests at Johnson Island, and arrived Long Beach 21 November.

In March 1963 the ship took part in another large amphibious operation, "Steelgate", then worked out of Long Beach before again joining Canadian ships for mine warfare exercises off British Columbia in November. She got underway for the western Pacific again 8 May 1964, and after stopping at various islands moved to the coast of South Vietnam in September for special operations supporting the American Advisory unit. After mine exercises off the Philippines she returned Long Beach 7 December 1964. The following 12 months were spent in tactics and exercises along the coast of southern California, overhaul at Los Angeles, and readiness operations to prepare her for another Far Eastern deployment assisting Allied forces to defend freedom in Southeast Asia.

[Note: The above USS IMPERVIOUS (MSO-449) history may, or may not, contain text provided by crew members of the USS IMPERVIOUS (MSO-449), or by other non-crew members, and text from the Dictionary of American Naval Fighting Ships]