USS Evarts, an example of the Evarts subclass.
Destroyer escort (DE) was the United States Navy mid-20th century classification for a 20-knot (23 mph) warship designed with endurance to escort mid-ocean convoys of merchant marine ships. Kaibōkan were designed for a similar role in the Imperial Japanese Navy. The Royal Navy and Commonwealth forces identified such warships as frigates, and that classification was widely accepted when the United States redesignated destroyer escorts as frigates (FF) in 1975. Destroyer escorts, frigates and kaibōkan were mass-produced for World War II as a less expensive anti-submarine warfare alternative to fleet destroyers.
Post-war destroyer escorts and frigates were larger than those produced during wartime, with increased anti-aircraft capability, but remained smaller and slower than post-war destroyers. As Cold War destroyer escorts became as large as wartime destroyers, the United States Navy converted some of their World War II destroyers to escort destroyers (DDE).
Full-size destroyers must be able to steam as fast or faster than the fast capital ships such as fleet carriers and cruisers. This typically requires a speed of 25–35 knots (46–65 km/h) (dependent upon the era and navy). They must carry torpedoes and a smaller caliber of cannon to use against enemy ships, as well as anti-submarine detection equipment and weapons.
A destroyer escort needed only to be able to maneuver relative to a slow convoy (which in World War II would travel at 10 to 12 knots (19 to 22 km/h)), and be able to defend against aircraft and detect, pursue and attack submarines. These lower requirements greatly reduce the size, cost, and crew required for the destroyer escort. Destroyer escorts were optimized for anti-submarine warfare, having a tighter turning radius and more specialized armament (such as the forward-firing Hedgehog mortar) than fleet destroyers. Their much slower speed was not a liability in this context, since sonar was useless at speeds over 20 knots (37 km/h). Destroyer escorts were also considerably more sea-kindly than corvettes.
As an alternative to steam turbine propulsion found in full size destroyers and larger warships, many US destroyer escorts of the World War II period had diesel-electric or turbo-electric drive, in which the engine rooms functioned as power stations supplying current to electric motors sited close to the propellers. Electric drive was selected because it does not need gearboxes (which were heavily in demand for the fast fleet destroyers) to adjust engine speed to the much lower optimum speed for the propellers. The current from the engine room can be used equally well for other purposes, and post-World War II many destroyer escorts were recycled as floating power stations for coastal cities in Latin America under programs funded by the World Bank.
Destroyer escorts were also useful for coastal anti-submarine and radar picket ship duty. During World War II, seven destroyer escorts (DEs) were converted to radar picket destroyer escorts (DERs), supplementing radar picket destroyers. Although these were relegated to secondary roles after the war, in the mid-1950s twelve more DEs were converted to DERs, serving as such until 1960-1965. Their mission was to extend the Distant Early Warning line on both coasts, in conjunction with sixteen Guardian-class radar picket ships, which were converted Liberty ships.
In World War II, some 95 destroyer escorts were converted by the US to high-speed transports (APDs). This involved adding an extra deck which allowed space for about 10 officers and 150 men. Two large davits were also installed, one on either side of the ship from which landing craft (LCVP) could be launched.
The Lend-lease Act was passed into law in the United States in March 1941 enabling the United Kingdom to procure merchant ships, warships, munitions and other materiel from the US, in order to help with the war effort. This enabled the UK to commission the US to design, build and supply an escort vessel that was suitable for anti-submarine warfare in deep open ocean situations, which they did in June 1941. Captain E.L. Cochrane of the American Bureau of Shipping came up with a design which was known as the British Destroyer Escort (BDE). The BDE designation was retained by the first six destroyer escorts transferred to the United Kingdom (BDE 1, 2, 3, 4, 12 and 46); of the initial order of 50 these were the only ones the Royal Navy received, the rest being reclassified as destroyer escort on 25 January 1943 and taken over by the United States Navy.
When the United States entered the war, and found they also required an anti-submarine warfare ship and that the destroyer escort fitted their needs perfectly, a system of rationing was put in place whereby out of every five destroyer escorts completed, four would be allocated to the U.S. Navy and one to the Royal Navy.
Post-World-War-II U.S. ship reclassification
After World War II United States Navy destroyer escorts were referred to as ocean escorts, but retained the hull classification symbol DE. However other navies, most notably those of NATO countries and the USSR, followed different naming conventions for this type of ship which resulted in some confusion. In order to remedy this problem the 1975 ship reclassification reclassified ocean escorts (and by extension, destroyer escorts) as frigates (FF). This brought the USN's nomenclature more in line with NATO, and made it easier to compare ship types with the Soviet Union (see Cruiser Gap). As of 2006 there are no plans for future frigates for the US Navy. USS Zumwalt and the Littoral Combat Ship (LCS) are the main ship types planned in this area. One major problem with ship classification is whether to base it on a ship's role (such as escort or air defense), or on its size (such as displacement). One example of this ambiguity are the Ticonderoga-class air-defense ships, which are classified as cruisers even though they use the same hull as the Spruance-class destroyers.
US Navy destroyer escort class overview
|Class Name||Lead Ship||Commissioned||Ships Built|
|Evarts (GMT) class||USS Evarts (DE-5)||15 April 1943||72|
|Buckley (TE) class||USS Buckley (DE-51)||30 April 1943||102|
|Cannon (DET) class||USS Cannon (DE-99)||26 September 1943||72|
|Edsall (FMR) class||USS Edsall (DE-129)||10 April 1943||85|
|Rudderow (TEV) class||USS Rudderow (DE-224)||15 May 1944||22|
|John C. Butler (WGT) class||USS John C. Butler (DE-339)||31 March 1944||87|
|Dealey class||USS Dealey (DE-1006)||3 June 1954||13|
|Claud Jones class||USS Claud Jones (DE-1033)||10 February 1959||4|
|Bronstein class||USS Bronstein (DE-1037)||15 June 1963||2|
|Garcia class||USS Garcia (DE-1040)||21 December 1964||10|
|Brooke class||USS Brooke (DEG-1)||12 March 1966||6|
|Knox class||USS Knox (DE-1052)||12 April 1969||46|
Captain-class frigates of the Royal Navy
The Captain class was a designation given to 78 frigates of the Royal Navy, constructed in the United States, launched in 1942–1943 and delivered to the United Kingdom under the provisions of the Lend-Lease agreement (under which the United States supplied the United Kingdom and other Allied nations with materiel between 1941 and 1945), they were drawn from two sub-classes of the destroyer escort (originally British destroyer escort) classification: 32 from the Evarts sub-class and 46 from the Buckley sub-class. Upon reaching the UK the ships were substantially modified by the Royal Navy including removal of torpedo tubes, making them distinct from the US Navy destroyer escort ships.
Captain-class frigates acted in the roles of convoy escorts, anti-submarine warfare vessels, coastal forces control frigates and headquarters ships for the Normandy landings. During the course of World War II this class participated in the sinking of at least 34 German submarines and a number of other hostile craft with 15 of the 78 Captain-class frigates being either sunk or written-off as a constructive total loss.
In the post-war period, all of the surviving Captain-class frigates except one (HMS Hotham) were returned to the US Navy before the end of 1947 in order to reduce the amount payable under the provisions of the Lend-Lease agreement; the last Captain-class frigate was returned to United States custody in March 1956.
Six Cannon-class destroyer escorts were built for the Free French Navy. Although initially transferred under the Lend-lease Act these ships were permanently transferred under the Mutual Defense Assistance Program.
List of Free French destroyer escorts
- FFL Algérien (F-1), ex-Cronin (DE-107)
- FFL Sénégalais (F-2), ex-Corbestier (DE-106)
- FFL Somali (F-3), ex-Somali (DE-111)
- FFL Hova (F-4), ex-Hova (DE-110)
- FFL Marocain (F-5), ex-Marocain (DE-109)
- FFL Tunisien (F-6), ex-Crosley (DE-108)
Mutual Defense Assistance Program - Post WWII
Under the Mutual Defense Assistance Program (MDAP) the Destroyer Escorts leased to the Free French were permanently transferred to the French Navy. In addition the following navies also acquired Destroyer Escorts:
Republic of China Navy (Taiwan)
- DE-1007, DE-1008, DE-1009, DE-1010, DE-1011, DE-1012, DE-1013, DE-1016, DE-1017, DE-1018, DE1019
- DE-1020, DE-1031
Japanese Maritime Self-Defense Force
- DE-1032, DE-1039, DE-1042, DE-1046
Republic of Korea Navy
Royal Netherlands Navy
- USS Burrows (DE-105), USS Rinehart (DE-196), USS Gustafson (DE-182), USS O'Neill (DE-188), USS Eisner (DE-192), USS Stern (DE-187)
Royal Thai Navy
National Navy of Uruguay
Comparison with contemporary frigates
The table below compares United States destroyer escorts with other destroyer escorts and frigates designed for similar missions.
|River-class frigate||1942||UK||1,370 tons||20 knots||151|
|Type A kaibōkan||1943||Japan||870 tons||19 knots||18|
|FMR class||1943||US||1,200 tons||21 knots||85|
|GMT class||1943||US||1,140 tons||21 knots||72|
|TE class||1943||US||1,400 tons||23 knots||102|
|DET class||1943||US||1,240 tons||21 knots||72|
|Tacoma-class frigate||1943||US||1,430 tons||20 knots||96|
|Type B kaibōkan||1943||Japan||940 tons||19 knots||37|
|Loch-class frigate||1944||UK||1,435 tons||20 knots||30|
|WGT class||1944||US||1,350 tons||24 knots||87|
|TEV class||1944||US||1,450 tons||24 knots||22|
|Bay-class frigate||1945||UK||1,580 tons||20 knots||26||anti-aircraft|
|Dealey class||1954||US||1,450 tons||25 knots||13|
|Type E50 frigate||1955||France||1,290 tons||28 knots||4||fast|
|Type 14 frigate||1955||UK||1,180 tons||24 knots||8||anti-submarine|
|St. Laurent class||1955||Canada||2,263 tons||28 knots||7||anti-submarine|
|Type B||1956||Japan||1,070 tons||25 knots||2||diesel|
|Type 12 frigate||1956||UK||2,150 tons||31 knots||6||anti-submarine|
|Type E52 frigate||1956||France||1,295 tons||28 knots||14||fast|
|Almirante Clemente-class light destroyer||1956||Venezuela||1,300 tons||32 knots||6||fast|
|Type 61 frigate||1957||UK||2,170 tons||24 knots||4||aircraft direction|
|Canopo-class frigate||1957||Italy||1,807 tons||26 knots||4|
|Type 41 frigate||1957||UK||2,300 tons||24 knots||4||anti-aircraft|
|Azopardo-class frigate||1957||Argentina||1,160 tons||20 knots||2|
|Restigouche class||1958||Canada||2,366 tons||28 knots||7||anti-submarine|
|Claud Jones class||1959||US||1,450 tons||22 knots||4|
|Type 12M frigate||1960||UK||2,380 tons||30 knots||12||anti-submarine|
|Köln-class frigate||1961||Germany||2,100 tons||30 knots||6||fast|
|River-class destroyer escort||1961||Australia||2,100 tons||30 knots||6||Originally designated as anti-submarine frigates, later re-designated as destroyer escorts.|
|Isuzu-class destroyer escort||1961||Japan||1,490 tons||25 knots||4|
|Type 81 frigate||1961||UK||2,300 tons||28 knots||7||general purpose|
|Bergamini-class frigate||1961||Italy||1,410 tons||26 knots||4|
|Commandant Rivière-class frigate||1962||France||1,750 tons||25 knots||13||dual purpose|
|Mackenzie class||1962||Canada||2,366 tons||28 knots||4||anti-submarine|
|Hvidbjørnen-class frigate||1962||Denmark||1,345 tons||18 knots||4||fishery protection|
|Type 12I frigate||1963||UK||2,450 tons||30 knots||26||general purpose|
|Bronstein class||1963||US||2,360 tons||26 knots||2|
|Garcia class||1964||US||2,620 tons||27 knots||10|
|Oslo-class frigate||1966||Norway||1,450 tons||25 knots||5|
|Brooke class||1966||US||2,640 tons||27 knots||6||guided missile|
|Peder Skram-class frigate||1966||Denmark||2,030 tons||28 knots||2||fast|
|Van Speijk-class frigate||1967||Netherlands||2,200 tons||28 knots||6|
|Alpino-class frigate||1968||Italy||2,000 tons||28 knots||2|
|Alvand-class frigate||1968||Iran||1,110 tons||40 knots||4|
|Knox class||1969||US||3,011 tons||27 knots||46|
|Chikugo-class destroyer escort||1971||Japan||1,470 tons||25 knots||11|
Surviving destroyer escorts
Three destroyer escorts are preserved as museum ships, while others remain in active service.
- The Edsall-class destroyer escort USS Stewart (DE-238) is preserved in Galveston, Texas.
- The Cannon-class destroyer escort USS Slater (DE-766) is preserved in Albany, New York.
- The Cannon-class destroyer escort BNS Bauru (BE-4), formerly USS McAnn (DE-179) is preserved in Rio de Janeiro, Brazil.
- The Cannon-class destroyer escort BRP Rajah Humabon (PF-11), formerly USS Atherton (DE-169), is active in the Philippine Navy.
- The Edsall-class destroyer escort HTMS Pin Klao (DE-1), formerly USS Hemminger (DE-746), is active in the Royal Thai Navy.
- The Edsall-class destroyer escort ARM Manuel Azueta (D-111), formerly USS Hurst (DE-250), is active in the Mexican Navy.
- The Japanese Maritime Self-Defense Force operates six Abukuma-class destroyer escorts.
- The Enemy Below for a movie filmed on a DE.
- Modern Naval tactics.
- List of destroyer escorts of the United States Navy
- List of frigates
- Ocean escort
- List of destroyers of the Second World War
- List of frigates of the Second World War
Notes and references
- DE-574 was originally provided to the United Kingdom under the Lend-Lease (Public Law 77-11) scheme, DE-574 was returned to the US custody under the provisions of the Lend-Lease scheme on the 25 April 1952 and simultaneously transferred back to the United Kingdom under the Mutual Defence Assistance Program.
- Blackman, pp. 393 & 394
- Watts, pp. 225-239
- Potter & Nimitz, p. 550
- Cooney, pp. 6 & 7
- NAVPERS, pp. 32 & 35
- Franklin 1999, p. 7.
- Silverstone, pp. 153-157
- Silverstone, pp. 157-163
- Silverstone, pp. 164-167
- Silverstone, pp. 167-170
- Silverstone, pp. 163 & 164
- Silverstone, pp. 170-175
- Blackman, p. 458
- Blackman, p. 457
- Blackman, p. 456
- Blackman, p. 455
- Blackman, p. 452
- Blackman, p. 453
- Lenton 1998, pp. 198–199.
- Morison 1956, p. 34.
- Collingwood 1998, pp. 30–31.
- Franklin 1999, p. x.
- DANFS: Hotham.
- Lenton 1974, p. 16.
- Lenton & Colledge, p. 225
- Silverstone, p. 246
- Lenton & Colledge, p. 232
- Blackman, p. 114
- Blackman, p. 354
- Blackman, p. 44
- Blackman, p. 199
- Blackman, p. 353
- Blackman, p. 113
- Blackman, p. 624
- Blackman, p. 356
- Blackman, p. 183
- Blackman, p. 355
- Blackman, p. 8
- Blackman, p. 43
- Blackman, p. 351
- Blackman, p. 127
- Blackman, p. 21
- Blackman, p. 198
- Blackman, p. 350
- Blackman, p. 182
- Blackman, p. 79
- Blackman, p. 348
- Blackman, p. 240
- Blackman, p. 78
- Blackman, p. 229
- Blackman, p. 167
- Blackman, Raymond V.B. (1970–71). Jane's Fighting Ships. Jane's Yearbooks.
- Collingwood, Donald (1998). The Captain class frigates in the second world war: an operational history of the American-built destroyer escorts serving under the White Ensign from 1943–46. Leo Cooper. ISBN 978-0-85052-615-8. Retrieved 24 May 2012.
- Cooney, David M. (1980). Ships, Aircraft and Weapons of the United States Navy. United States Government Printing Office.
- Franklin, Bruce Hampton (1999). The Buckley-Class Destroyer Escorts. Chatham Publishing. ISBN 1-86176-118-X.
- Lenton, H T. (1998). British and Empire Warships of the Second World War. Greenhill Books/Naval Institute Press. ISBN 1-85367-277-7. Retrieved 24 May 2012.
- Lenton, H.T. (1974). British Escort Ships. Macdonald and Jane's. ISBN 0-356-08062-5. Retrieved 24 May 2012.
- Morison, Samuel Eliot (1956). History of United States Naval Operations in World War II. Vol. 10: The Atlantic Battle Won, May 1943 – May 1945. Little, Brown and Company. ISBN 978-0316583107. Retrieved 24 May 2012.
- NAVPERS (1955). Warship Identification Manual. United States Government Printing Office.
- Potter, E.B.; Nimitz, Chester W. (1960). Sea Power. Prentice-Hall.
- Silverstone, Paul H. (1968). U.S. Warships of World War II. Doubleday & Company.
- Watts, Anthony J. (1966). Japanese Warships of World War II. Doubleday & Company.
- For an excellent book on the subject of a particular example of this type of ship in World War II, the USS Abercrombie (DE-343) see Little Ship, Big War: The Saga of DE-343 by Edward Peary Stafford. Naval Institute Press, 2000 ISBN 1-55750-890-9
- For an excellent book on the subject of the Captains class frigate variant of the Destroyer Escort in World War II, see The Captain Class Frigates in the Second World War by Donald Collingwood. published by Leo Cooper (1998), ISBN 0-85052-615-9.
- Destroyers and escort ships at Encyclopædia Britannica
- DESA - Destroyer Escort Sailors Association
- Destroyer Escort Historical Museum, Albany, NY
- Seawolf Park GALVESTON
- Free cardstock model plan of Butler class Destroyer Escort, to print off and assemble.
- USS Slater Photos on board the Destroyer Escort USS Slater DE-766
- USS Bangust WWII Photos of life on board the Destroyer Escort USS Bangust DE-739 in WWII
- Destroyer Escort Bangust DE-739 Home Page
- Captains Class Frigates
- Escort http://www.uboat.net/
- Why DE boats are death to subs August 1943 Popular Science article on destroyer escort with large illustration