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FIGHTING SHIPS OF THE WORLD
UNITED STATES OF AMERICA
MINE WARFARE SHIPS
AGGRESSIVE ocean minesweepers (1953 - 1958)


Photo



Embattle 1963

Ships


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


Technical data


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



Graphics


<i>Affray</i> 1983
Affray 1983
<i>Exploit </i>1969
Exploit 1969
<i>Embattle </i>1963
Embattle 1963


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.