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Destroyer escorts were oceangoing antisubmarine
vessels that carried a destroyer’s
complement of depth charges
and other antisubmarine gear, but not
the full surface and antiaircraft
weaponry. They were also
destroyers, not nearly as fast (20 knots, about as fast as a surfaced
submarine), and easier to build.
They were designed for convoy
rather than fleet operations.
Large numbers of destroyer escorts were constructed by the British and Americans, and they proved effective in both the Atlantic and the Pacific. One destroyer escort, the England, sank six Japanese submarines out of a patrol line whose location had been uncovered by the code breakers. The Japanese did not start building their equivalent of destroyer escorts until 1943, which was very late in the game, and they were never built in sufficient numbers.
Destroyer Escort Program. The U.S. Navy had discussed
constructing small, inexpensive destroyers
for convoy escort before the war, but there was reluctance to build
what were viewed as second-class destroyers. Instead, Navy planners
assumed that an existing destroyer design (such as the Farragut) could be adapted for mass
production if necessary. However, British
experienced in 1940 made it clear that great numbers of
vessels were required for escort duty. Prodded by the British, who
desired to acquire such vessels under Lend-Lease, the Americans
serious study of the concept. In June 1941 the
British military mission requested 100 vessels based on a U.S. Navy
conceptual design for a 280' (85m) ship with two 5"/38 dual-purpose guns and a
bank, as well as extensive antisubmarine gear, capable of 24 knots. A
speed of 24 knots was considered the minimum necessary for escorting
fast troop transports and for
providing the acceleration required by antisubmarine tactics. The
specifications also called for a double rudder to provide the required
Americans initially planned to build a vast number of destroyer escorts
(over a thousand were ordered) to a single design, but because of
shortages of both 5" guns and machinery,
six distinct classes were eventually built on the same basic plan. The Evarts
were armed with 3" guns and used diesel engines; when these proved
badly underpowered, with a maximum speed far short of the desired 24
knots, production shifted to the Buckley
and Rudderow classes. These used
more powerful turboelectric machinery that gave a speed just short of
the desired 24 knots, but required a somewhat longer hull.
The Buckleys were armed
with 3" guns while the Rudderows
were armed with 5" guns. The longer hull became standard, even when
production shifted back to lower power diesel-electric (Cannon
class) or diesel (Edsall class) engines, or to
steam turbine engines (John C. Butler class). The Cannons and Edsalls had 3" guns while the John C. Butlers were armed with 5"
guns. Because of the shortage of 5" guns, none were mounted on the
classes with less powerful machinery. All had powerful antisubmarine armament, including QC sonar, multiple depth charge throwers, and Hedgehog (which was not installed on American fleet destroyers).
The ships proved very stable, which allowed them to ship considerable additional equipment. However, British officers complained that the ships were too stable, recovering from rolling so abruptly that crews were exhausted from the constant lurching and accurate gunnery was impossible. One British captain wrote acidly that
Rolling -- since this report is written
at sea it is difficult to describe with reticence the nauseating
movement of these vessels in the open sea ....
The violent "lurching" is the principal controlling factor in efficiency. As gun platforms these ships are satisfactory only under the most favorable weather....
Depth charge reloading is possible in a moderate heavy sea pounding the ship.... Under average conditions however it must be an even bet whether the throwers lob their charges vertically upwards and on to the quarter deck or immediately alongside propellers....
... these ships present no problem at all as to damage control. There is none.
(Friedman 2004.) The British modified the ships with deeper bilge keels that greatly reduced the rolling, much to the satisfaction of their officers. However, congested shipyards in both Britain and the United States meant that it took some time to complete the improvements.
Destroyer escort construction competed heavily with landing craft, and orders for new units began to be canceled, starting in September 1943. Other units were converted to fast transports.
British Escort Destroyers. The British acquired a large number
of American destroyer escorts under Lend-Lease as the "Captain" class.
The British also constructed a large number of small destroyers as the "Hunt" class.
These were described as escort destroyers and likely inspired the
American destroyer escort program, but differed from the American ships
in having somewhat better speed (about 27 knots) and heavier
antiaircraft armament. The program nearly came to disaster when
inclination tests of the first hull showed that her metacentric height
had been miscalculated by the designers and she would be too unstable to
be seaworthy if completed as designed. Hasty design changes restored
the necessary stability for the first group, and two additional groups
with various improvements were ordered.
Few of the British escort destroyers were deployed to the Far East,
and that late in the war. However, a handful arrived in time to
participate in occupation operations in southeast Asia, and they
doubtless would have participated in the invasion of Japan had that actually taken place.
Destroyer Escort Program. The Japanese suffered crippling
destroyer losses in the Solomons
in 1942. While the standard Yugumo destroyer class was an
excellent design, its construction took far too long to make good the
Japanese losses. The Japanese Navy therefore rushed a new design into
production (the Matsu class) that emphasized
ease of construction and survivability. These were designated as
destroyers but resembled the American destroyer escorts, being slightly
smaller but faster and better armed. Further simplifications to speed
up construction resulted in the Tachibana design.
John C. Butler class
"Hunt" II class
"Hunt" III class
"Hunt" IV class
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