UNITED STATES NAVY (UNITED STATES OF AMERICA)

Ship project history: Necessity for building, along with destroyers, of smaller and cheaper ships was advanced by a number of officers and admirals of the American Navy in 1939. Such "2nd rank" destroyers could fulfil successfully convoys escort and solve many auxiliary tasks, abstraction on which of destroyers was inexpedient. Oroginally General Board has disapproved of building of similar ships, but next year situation has cardinally changed, and as a result some projects have been prepared. Any of them was not been accepted, as the American designers have tried to go on a way of decreasing of usual destroyer to 1000-1200t displacement, having stored thus her basic armament. As a result very cramped arrangement with unsatisfactory combination of leading particulars was received.

In spite of the fact that the project has not been finished yet, in January, 1941 the decision on building of such 50 destroyers was accepted. That though somehow to boost process of designing, the General board in February changed requirements on speed (not less than 25kts.) and to armament structure (earlier it was provided to install DP 127mm guns). Soon new project was ready: 1140t displacement, 85.3m length, 24kts speed, 2 single 102/50mm or 127/38mm single-purpose guns, 1 quadruple 40mm Bofors, 2 single 20mm Oerlikons and 1 triple TT. General board approved project, however in such kind it was never realised: in May, 1941 this program was cancelled. Probably destroyer escort also would not appear at all, but unexpectedly the help has come from Britain. British commission has become interested in the project and 23/6/1941 directed inquiry about possibility of building of 100 similar ships, with replacement of SP by 3 single 76/50mm AA guns, installation of twin rudders for improvement of manoeuvrability and retuning under the British standard of bridge. Specified corrections have been brought in the project, and already 15/8/1941 plan of building of 50 ships for UK was approved by Roosevelt. Simultaneously the American Navy HQ convinced the president to begin building of similar ships for own navy, but this sentence has been rejected. Only in November, 1941 the order for first DE for USN has followed.

After the introduction of the USA into war congestion of the industry by various defence orders has led to necessity of including to project of significant changes concerning machinery. Originally provided 12000hp twin-shaft geared steam turbines was replaced by diesel, diesel-electric or turbo-electric machinery and only small part of ships was equipped by geared turbines. Besides, new machinery required more spacious engine room and, consequently, lengthened hull.

In the project the displacement reserve for armament strengthening (replacement of three 76mms openly standing guns by two 127mm in enclosed mounts) was included, as has been realised in late series.

In total there were six series of destroyer escorts:

Evarts class (GMT): 6000hp diesel-electric machinery (4 1500hp diesels-generators, 2 electric motors), 76mm guns, "short" hull.

Cannon class (DET): 6000hp diesel-electric machinery (4 1500hp diesels-generators, 2 electric motors), 76mm guns, "long" hull.

Edsall class (FRM): 6000hp diesel machinery (4 1500hp diesels working through gears on 2 shafts), 76mm guns, "long" hull.

Buckley class (TE): 12000hp turbo-electric machinery, 76mm guns, "long" hull.

Rudderow class (TEV): 12000hp turbo-electric machinery, 127mm guns, "long" hull.

John С. Butler class (WGT): 12000hp geared steam turbine machinery, 127mm guns, "long" hull.

In 1944 when the number of escorts on Atlantic has been recognised by sufficient, large number of DEs of Buckley and Rudderow classes were converted to fast landing transports for service on Pacific. Thus they received the superstructure expanded to sides, all anti-submarine armament (except two DCR) part of artillery and torpedoes were removed . After conversion such transport could carry up to 162 rangers for which landing 4 LCVP were available.

In addition to above, many old destroyers and destroyer escorts were converted to fast transports, as follows:

APD1 - Caldwell class

APD2 - 9, 14 - 17, 19 - 22, 25 - Wickes class

APD10 - 13, 18, 23, 24, 29, 31 - 36 - Clemson class

APD37 - 40, 42 - 57, 59 - 63, 65, 66, 75 - 81, 84 - 86 - "TE" (Buckley) class

APD139 - "TEV" (Rudderow) class

Conversion of DE635 (planned APD41), 636 (58), 214 (64), 665 (67), 666 (68), 790 (82), 791 (83) of "TE" class and DE684 (137), 685 (138) of "TEV" class was not started.

Modernizations: None.

Naval service: No significant events.