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UNITED STATES OF AMERICA

COASTAL FORCES

110ft submarine chasers of WWII (1942-1944)

SC677 1943

SC1025 1945

Project history: In days of the First World War in the USA the big number of 110ft submarine chasers has been built. Secretary of Navy Roosevelt (future President) participated in development of building of this huge series on small shipyards. When in 1937 leading particulars of ASW ship intended for patrol in coastal areas and on fleet anchoring were defined, Roosevelt has insisted on return to project of twenty years' prescription, which at building was criticised for the small displacement and insufficient endurance. Perhaps, unique concessions for technical progress were a choice of diesels as main engines and installation of sonar.

Under the FY1938 program three experimental chasers under some differing projects (SC449, SC450 and SC453) were built. Latter, designed by the Navy, also has formed a basis for serial chasers. She differed from the predecessor of WWI times in the increased breadth and stronger hull structure with application of steel bracings.

Serial SCs were developed from SC453. Chasers of different years of building differed by armament structure. Only some lead boats received designed armament, since 1942 DCT "Mousetrap" was fitted, and 12.7mm MGs were replaced by 20mm Oerlikons; since 1943 newly built ships instead of out-of-date 76mm/23 gun received 76mm/50, and ASW armament was strengthened by two DCTs. In 1944 replacement of 76mm/23 guns by 40mm "Boforses" started and by next year in the US Navy only 4 chasers old short gun were remained.

Shortages of diesels of eligible power led to that 231 chasers received 500hp diesels instead of 1200hp. Maximal speed of such boats was limited by 16kts.

In 1944 eight hunters were converted to motor gunboats for  operations against Japanese boats and had index PGM. After rearming their armament consisted from single 76mm/23 gun and single 40mm/56 Bofors or 2 single 40mm/56 Boforses; 4 twin 12.7mm MGs, 1 single 60mm mortar and multi-barrelled 83mm Bazooka.

In 1944 35 SCs were converted to command and control ships of amphibious forces SC(C).

Modernizations: 1942, earlier SC497 class chasers were re-armed as new built ones.

1942 -1943, earlier SC497 class chasers were re-armed as new built ones.

12.1943, SC644, 757, 1035, 1053, 1056, 1071, 1072 and 1366 were converted to gunboats: - 1 x 1 - 76/23, 2 x 1 - 20/70, 2 x 4 - 178 Mousetrap ASWRL, 2 DCT, 1 DCR; + (1 x 1 - 76/23 Mk 14, 1 x 1 - 40/56 Mk 1.2) or 2 x 1 - 40/56 Mk 1.2, 4 x 2 - 12.7/90, 1 x 1 - 60/12 M19 mortar, 1 multi-barreled Bazooka grenade launcher

1943 - 1944, earlier SC497 class chasers were re-armed as new built ones.

1944, 35 units were converted to SC(C) amphibious command ships: - 2 x 1 - 20/70, 2 DCT, 2 DCR

1.1946, SC: 1 x 1 - 40/60 Mk 3, 3 x 1 - 20/70 Mk 10, 2 x 4 - 178 Mousetrap Mk 20 ASWRL, 2 DCT, 2 DCR (34), SF or SO or SU or SCR-517A or SW-1C radar, QC sonar

1.1946, PGM: (1 x 1 - 76/23 Mk 14, 1 x 1 - 40/60 Mk 3) or 2 x 1 - 40/60 Mk 3, 4 x 2 - 12.7/90, 1 x 1 - 60/12 M19 mortar, 1 x 4 - 57/27 M9A1 Bazooka launcher, SF or SO or SU or SCR-517A or SW-1C radar

1.1946, SC(C): 1 x 1 - 40/60 Mk 3, 1 x 1 - 20/70 Mk 10, 2 x 4 - 178 Mousetrap MK 20 ASWRL, SF or SO or SU or SCR-517A or SW-1C radar, QC sonar

Naval service: SC694 and 696 were sunk by German aircraft and SC744 by kamikaze.

SC724 1942

© Ivan Gogin, 2014-15