Agile 1963
Aggressive 1963
Agile 1970
Pivot 1972
Engage 1979
No | Name | Yard No | Builder | Laid down | Launched | Comm | Fate |
MSO421 | Agile | Luders Marine, Stamford | 2.1954 | 19.11.1955 | 6.1956 | stricken 9.1977 | |
AM422, 2.1955- MSO422 | Aggressive | Luders Marine, Stamford | 5.1951 | 4.10.1952 | 11.1953 | stricken 2.1975 | |
AM423, 1.1955- MSO423 | Avenge | Luders Marine, Stamford | 8.1951 | 15.3.1953 | 5.1954 | stricken 2.1970 | |
AM424, 2.1955- MSO424 | Bold | Norfolk N Yd, Portsmouth | 12.1951 | 14.3.1953 | 9.1953 | stricken 2.1975 | |
AM425, 2.1955- MSO425 | Bulwark | Norfolk N Yd, Portsmouth | 12.1951 | 14.3.1952 | 11.1953 | stricken 2.1975 | |
AM426, 2.1955- MSO426 | Conflict | Fulton, Antioch | 8.1951 | 16.12.1952 | 3.1954 | stricken 6.1972 | |
AM427, 2.1955- MSO427 | Constant | Fulton, Antioch | 8.1951 | 14.2.1953 | 9.1954 | stricken 3.1994 | |
AM428, 2.1955- MSO428 | Dash | Astoria Marine | 7.1951 | 20.9.1952 | 8.1953 | sold 1.1984 | |
AM429, 2.1955- MSO429 | Detector | Astoria Marine | 10.1951 | 5.12.1952 | 1.1953 | stricken 12.1983 | |
AM430, 2.1955- MSO430 | Direct | Hiltebrant, Kingston | 2.1952 | 27.5.1953 | 7.1954 | stricken 10.1982 | |
AM431, 2.1955- MSO431 | Dominant | Hiltebrant, Kingston | 4.1952 | 5.11.1953 | 11.1954 | sold 1.1984 | |
AM432, 2.1955- MSO432 | Dynamic | Colberg, Stockton | 10.1951 | 17.12.1952 | 12.1953 | to Spain 7.1971 (Guadalete) | |
AM433, 2.1955- MSO433 | Engage | Colberg, Stockton | 11.1951 | 18.6.1953 | 6.1954 | stricken 4.1992 | |
AM434, 2.1955- MSO434 | Embattle | Colberg, Stockton | 11.1951 | 27.8.1953 | 11.1954 | stricken 5.1976 | |
AM435, 2.1955- MSO435 | Endurance | Martinac, Tacoma | 1.1952 | 8.8.1952 | 5.1954 | stricken 7.1972 | |
AM436, 2.1955- MSO436 | Energy | Martinac, Tacoma | 3.1952 | 13.2.1953 | 7.1954 | to Philippines 7.1972 (Davao del Norte) | |
MSO437 | Enhance | Maritinolich, San Diego | 7.1952 | 11.10.1952 | 4.1955 | stricken 2.1992 | |
MSO438 | Esteem | Maritinolich, San Diego | 9.1952 | 20.12.1952 | 9.1955 | stricken 9.1991 | |
MSO439 | Excel | Higgins, New Orleans | 2.1953 | 25.9.1953 | 2.1955 | stricken 3.1994 | |
AM440, 2.1955- MSO440 | Exploit | Higgins, New Orleans | 12.1951 | 10.4.1953 | 3.1954 | stricken 3.1994 | |
AM441, 2.1955- MSO441 | Exultant | Higgins, New Orleans | 5.1952 | 6.6.1953 | 3.1954 | stricken 3.1994 | |
AM442, 2.1955- MSO442 | Fearless | Higgins, New Orleans | 7.1952 | 17.7.1953 | 9.1954 | stricken 10.1990 | |
AM443, 2.1955- MSO443 | Fidelity | Higgins, New Orleans | 12.1952 | 21.8.1953 | 1.1955 | stricken 6.1989 | |
AM444, 2.1955- MSO444 | Firm | Martinac, Tacoma | 4.1952 | 15.4.1953 | 10.1954 | to Philippines 7.1972 (Davao del Sur) | |
AM445, 2.1955- MSO445 | Force | Martinac, Tacoma | 8.1952 | 26.6.1953 | 1.1955 | fire 24.4.1973 | |
AM446, 2.1955- MSO446 | Fortify | Seattle SB | 11.1951 | 19.2.1953 | 7.1954 | stricken 3.1994 | |
MSO447 | Guide | Seattle SB | 2.1953 | 17.4.1954 | 3.1955 | stricken 7.1972 | |
AM448, 2.1955- MSO448 | Illusive | Martinolich, San Diego | 10.1951 | 12.7.1952 | 11.1953 | stricken 6.1990 | |
AM449, 2.1955- MSO449 | Impervious | Martinolich, San Diego | 11.1951 | 29.8.1952 | 7.1954 | stricken 3.1992 | |
AM455, 2.1955- MSO455 | Implicit | Wilmington BW | 10.1952 | 1.8.1953 | 3.1954 | to Taiwan 9.1994 (永陽 [Yung Yang]) | |
AM456, 2.1955- MSO456 | Inflict | Wilmington BW | 10.1952 | 16.10.1953 | 5.1954 | stricken 5.1990 | |
AM457, 2.1955- MSO457 | Loyalty | Wilmington BW | 11.1951 | 22.11.1953 | 6.1954 | stricken 7.1972 | |
MSO458 | Lucid | Higgins, New Orleans | 3.1953 | 14.11.1953 | 5.1955 | stricken 5.1976 | |
MSO459 | Nimble | Higgins, New Orleans | 4.1953 | 6.8.1954 | 5.1955 | stricken 11.1976 | |
MSO460 | Notable | Higgins, New Orleans | 6.1953 | 15.10.1954 | 6.1955 | stricken 2.1971 | |
MSO461 | Observer | Higgins, New Orleans | 7.1953 | 19.10.1954 | 8.1955 | stricken 9.1977 | |
MSO462 | Pinnacle | Higgins, New Orleans | 8.1953 | 3.1.1955 | 10.1955 | stricken 11.1977 | |
AM463, 2.1955- MSO463 | Pivot | Wilmington BW | 3.1952 | 9.1.1954 | 7.1954 | to Spain 7.1971 (Guadalmedina) | |
AM464, 2.1955- MSO464 | Pluck | Wilmington BW | 3.1952 | 6.2.1954 | 8.1954 | stricken 1.1991 | |
AM465, 2.1955- MSO465 | Prestige | Wilmington BW | 4.1952 | 30.4.1954 | 9.1954 | wrecked 23.8.1958 | |
AM466, 2.1955- MSO466 | Prime | Wilmington BW | 12.1952 | 27.5.1954 | 10.1954 | stricken 10.1976 | |
AM467, 2.1955- MSO467 | Reaper | Wilmington BW | 5.1952 | 25.6.1954 | 11.1954 | stricken 2.1975 | |
AM468, 2.1955- MSO468 | Rival | Luders Marine, Stamford | 2.1952 | 15.8.1953 | 9.1954 | stricken 2.1971 | |
AM469, 2.1955- MSO469 | Sagacity | Luders Marine, Stamford | 10.1952 | 26.2.1954 | 1.1955 | stricken 10.1970 | |
MSO470 | Salute | Luders Marine, Stamford | 3.1953 | 14.8.1954 | 5.1955 | stricken 2.1971 | |
MSO471 | Skill | Luders Marine, Stamford | 8.1953 | 3.4.1955 | 11.1955 | stricken 9.1977 | |
AM472, 2.1955- MSO472 | Valor | Burger Boat, Manitowoc | 4.1952 | 13.5.1953 | 7.1954 | stricken 2.1971 | |
AM473, 2.1955- MSO473 | Vigor | Burger Boat, Manitowoc | 6.1952 | 23.6.1953 | 11.1954 | to Spain 4.1972 (Guadiana) | |
MSO474 | Vital | Burger Boat, Manitowoc | 10.1952 | 12.8.1953 | 6.1955 | stricken 9.1977 | |
MSO488 | Conquest | Martinac, Tacoma | 3.1953 | 20.5.1954 | 7.1955 | stricken 6.1994, to Taiwan (永慈 [Yung Tzu]) | |
MSO489 | Gallant | Martinac, Tacoma | 5.1953 | 4.6.1954 | 9.1955 | stricken 4.1994, to Taiwan (永固 [Yung Ku]) | |
MSO490 | Leader | Martinac, Tacoma | 9.1953 | 15.9.1954 | 11.1955 | stricken 3.1992 | |
MSO491 | Persistent | Martinac, Tacoma | 6.1954 | 23.4.1955 | 2.1956 | to Spain 7.1971 (Guadalquivir) | |
MSO492 | Pledge | Martinac, Tacoma | 6.1954 | 20.7.1955 | 4.1956 | stricken 1.1994, to Taiwan (永德 [Yung Teh]) | |
MSO493 | Stalwart | Boward Marine, Fort Lauderdale | 6.1954 | 3.12.1955 | 4.1957 | fire 25.6.1966 | |
MSO494 | Sturdy | Boward Marine, Fort Lauderdale | 10.1954 | 28.1.1956 | 10.1957 | stricken 9.1977 | |
MSO495 | Swerve | Boward Marine, Fort Lauderdale | 12.1954 | 1.11.1955 | 7.1957 | sold 2.1978 | |
MSO496 | Venture | Boward Marine, Fort Lauderdale | 1.1955 | 27.11.1956 | 2.1958 | stricken 9.1977 | |
MSO508 | Acme | Frank Sample, Boothbay Harbor | 11.1954 | 23.6.1955 | 3.1957 | stricken 5.1976 | |
MSO509 | Adroit | Frank Sample, Boothbay Harbor | 11.1954 | 20.8.1955 | 3.1957 | stricken 5.1992 | |
MSO510 | Advance | Frank Sample, Boothbay Harbor | 6.1955 | 12.7.1956 | 6.1958 | stricken 5.1976 | |
MSO511 | Affray | Frank Sample, Boothbay Harbor | 8.1955 | 18.12.1956 | 12.1958 | stricken 6.1993 |
Displacement standard, t |
637 |
Displacement full, t |
735 |
Length, m |
50.3 wl 52.3 oa |
Breadth, m |
10.4 |
Draught, m |
4.00 |
No of shafts |
2 |
Machinery |
MSO421 - 427, 432 - 449, 455 - 474, 488 - 496, 508 - 511: 4 Packard diesels MSO428 - 431: 2 General Motors diesels |
Power, h. p. |
MSO421: 3040 MSO422 - 427, 432 - 449, 455 - 474, 488 - 496, 508 - 511: 2280 MSO428 - 431: 1520 |
Max speed, kts |
MSO421: 15 MSO422 - 427, 432 - 449, 455 - 474, 488 - 496, 508 - 511: 14 MSO428 - 431: 13 |
Fuel, t |
diesel oil |
Endurance, nm(kts) |
2400(12) |
Armament |
1 x 1 - 40/60 Mk 3, 2 x 1 - 12.7/90, A Mk 2, A Mk 4, A Mk 6 acoustic, M Mk 5, M Mk 6, M Mk 7 magnetic, Oropesa No.1 wire minesweeping gear |
Electronic equipment |
SPS-53 radar, UQS-1 sonar |
Complement |
70 |
Project history: Although minesweeper design continued after 1945, and although the prototype new ocean sweeper was authorised under the FY50 programme, construction on a large scale did not begin until the Korean War, with ten units under the FY51 first supplemental budget, eighteen under the second, and fifteen under die third, another five being planned under the FY52 programme. The new sweeper was somewhat smaller than the 180ft Second World War type, and it was built of plywood for minimum magnetic signature. Two XMAP pressure sweeping caissons could be towed. Given problems in diesel engine procurement under what were then expected to be mobilisation conditions, designs were prepared for either a new Packard light-weight engine or for an existing GM commercial type. Reportedly the rapid development of the Packard (which was also used in the new coastal sweepers) and its aircraft-type design led to many mechanical problems, which were not corrected for as much as eight years after us introduction. Given its unfortunate reputation, the Packard never saw large-scale commercial service, and the Navy suffered again as production ended and spares were largely unavailable. Of ninety-three ships to the SCB-45A or Agile class design, fifty-eight were retained by the US Navy, the others being transferred.
The Acme (MSO508) and Ability (MSO519) classes were improved and slightly enlarged Agiles built under the FY54 and 55 programme, the latter designed as mine division flagships. Ultimately both series were fitted as flagships.
All of the new ocean sweepers were built of wood with bronze and stainless (non-magnetic) steel fittings, with automatic degaussing, to compensate for course changes, as well as electrical insulators in internal piping, lifelines, and stays. All also had a new mine-locating sonar, UQS-1, later replaced by SQQ-14, a variable-depth unit on a rigid retractable rod.
Modernizations: 1969, Engage, Exultant, Fearless, Fidelity, Force, Fortify, Impervious, Inflict; 1970, Enhance, Esteem, Illusive, Conquest, Leader: main diesels were replaced by 4 Waukesha (2280hp); - 1 x 1 - 40/60, UQS-1 sonar; + SQQ-14 sonar.
Naval service: Force was lost by fire off Guam 24.4.1973. Prestige ran aground 23.8.1958 in Naruto Straits (Japanese Inland Sea) and abandoned as CTL. Stalwart was lost by fire at San Juan (Perto Rico) 25.6.1966.
Embattle 1963
Exploit 1969
Affray 1983
© Ivan Gogin, 2015