Destroyer escort

USS Evarts, an example of the Evarts subclass.
Class overview
Operators:
Subclasses:

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.[1] Kaibōkan were designed for a similar role in the Imperial Japanese Navy.[2] 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.[3]

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.[4] 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).[5]

General description

USS Dealey

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.

Origins

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.[6]

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.

Vietnam War

During the Vietnam War, the Republic of Vietnam Navy received two Edsall-class destroyer escorts from the United States.

US Navy destroyer escort class overview

Class name Lead ship Commissioned Ships built
Evarts (GMT) class[7] USS Evarts (DE-5) 15 April 1943 72
Buckley (TE) class[8] USS Buckley (DE-51) 30 April 1943 102
Cannon (DET) class[9] USS Cannon (DE-99) 26 September 1943 72
Edsall (FMR) class[10] USS Edsall (DE-129) 10 April 1943   85
Rudderow (TEV) class[11] USS Rudderow (DE-224) 15 May 1944 22
John C. Butler (WGT) class[12] USS John C. Butler (DE-339)   31 March 1944 87
Dealey class[13] USS Dealey (DE-1006) 3 June 1954 13
Claud Jones class[14] USS Claud Jones (DE-1033) 10 February 1959 4
Bronstein class[15] USS Bronstein (DE-1037) 15 June 1963 2
Garcia class[16] USS Garcia (DE-1040) 21 December 1964 10
Brooke class[17] USS Brooke (DEG-1) 12 March 1966 6
Knox class[18] USS Knox (DE-1052) 12 April 1969 46

Captain-class frigates of the Royal Navy

HMS Dacres, converted to act as a headquarters ship during Operation Neptune

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),[19][20] 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.[6][19] 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.[21]

Captain-class frigates acted in the roles of convoy escorts, anti-submarine warfare vessels,[22] 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.[23][24]

Free French

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

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-47, DE-6

French Navy

DE-1007, DE-1008, DE-1009, DE-1010, DE-1011, DE-1012, DE-1013, DE-1016, DE-1017, DE-1018, DE1019

Hellenic Navy

DE-173, DE-766, DE-768, DE-193

Italian Navy

DE-1020, DE-1031

Japanese Maritime Self-Defense Force

DE-168, DE-169

Philippine Navy

DE-168, DE-169, DE-170, DE-770, DE-771, DE-251, DE-637

Portuguese Navy

DE-1032, DE-1039, DE-1042, DE-1046

Republic of Korea Navy

DE-770, DE-771

Royal Navy

DE-574[note 1][23]

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

DE-746

National Navy of Uruguay

DE-166, DE-189,

Comparison with contemporary frigates

The table below compares destroyer escorts and frigates designed for similar missions.

Name Date Nation Displacement Speed Number built Notes
River-class frigate 1942 UK 1,370 tons 20 knots 151 [25]
Type A kaibōkan 1943 Japan 870 tons 19 knots 18 [2]
FMR class 1943 US 1,200 tons 21 knots 85 [10]
GMT class 1943 US 1,140 tons 21 knots 72 [7]
TE class 1943 US 1,400 tons 23 knots 102 [8]
DET class 1943 US 1,240 tons 21 knots 72 [9]
Tacoma-class frigate 1943 US 1,430 tons 20 knots 96 [26]
Type B kaibōkan 1943 Japan 940 tons 19 knots 37 [2]
Loch-class frigate 1944 UK 1,435 tons 20 knots 30 [27]
WGT class 1944 US 1,350 tons 24 knots 87 [12]
TEV class 1944 US 1,450 tons 24 knots 22 [11]
Bay-class frigate 1945 UK 1,580 tons 20 knots 26 anti-aircraft[27]
Dealey class 1954 US 1,450 tons 25 knots 13 [13]
Type E50 frigate 1955 France 1,290 tons 28 knots 4 fast[28]
Type 14 'Blackwood' frigate 1955 UK 1,180 tons 24 knots 15 "second-rate" anti-submarine warfare frigates. Cheaper to produce than Type 12.[29]
St. Laurent class 1955 Canada 2,263 tons 28 knots 7 anti-submarine[30]
Type B 1956 Japan 1,070 tons 25 knots 2 diesel[31]
Type 12 'Whitby' frigate 1956 UK 2,150 tons 31 knots 6 anti-submarine[32]
Type E52 frigate 1956 France 1,295 tons 28 knots 14 fast[33]
Almirante Clemente-class light destroyer 1956 Venezuela 1,300 tons 32 knots 6 fast[34]
Type 61 'Salisbury' frigate 1957 UK 2,170 tons 24 knots 4 aircraft direction[35]
Canopo-class frigate 1957 Italy 1,807 tons 26 knots 4 [36]
Type 41 'Loepard' frigate 1957 UK 2,300 tons 24 knots 7 anti-aircraft escort for convoys[37]
Azopardo-class frigate 1957 Argentina 1,160 tons 20 knots 2 [38]
Restigouche class 1958 Canada 2,366 tons 28 knots 7 anti-submarine[39]
Claud Jones class 1959 US 1,450 tons 22 knots 4 [14]
Type 12M 'Rothesay' frigate 1960 UK 2,380 tons 30 knots 12 ."Modified" Type 12. Anti-submarine[40]
Köln-class frigate 1961 Germany 2,100 tons 30 knots 6 fast[41]
River-class destroyer escort 1961 Australia 2,100 tons 30 knots 6 Originally designated as anti-submarine frigates, later re-designated as destroyer escorts.[42]
Isuzu-class destroyer escort 1961 Japan 1,490 tons 25 knots 4 [43]
Type 81 'Tribal' frigate 1961 UK 2,300 tons 28 knots 7 general purpose[44]
Bergamini-class frigate 1961 Italy 1,410 tons 26 knots 4 [45]
Commandant Rivière-class frigate 1962 France 1,750 tons 25 knots 13 dual purpose[33]
Mackenzie class 1962 Canada 2,366 tons 28 knots 4 anti-submarine[39]
Hvidbjørnen-class frigate 1962 Denmark 1,345 tons 18 knots 4 fishery protection[46]
Type 12I 'Leander' frigate 1963 UK 2,450 tons 30 knots 26 "Improved" Type 12. General purpose.[47]
Bronstein class 1963 US 2,360 tons 26 knots 2 [15]
Garcia class 1964 US 2,620 tons 27 knots 10 [16]
Oslo-class frigate 1966 Norway 1,450 tons 25 knots 5 [48]
Brooke class 1966 US 2,640 tons 27 knots 6 guided missile[17]
Peder Skram-class frigate 1966 Denmark 2,030 tons 28 knots 2 fast[49]
Van Speijk-class frigate 1967 Netherlands 2,200 tons 28 knots 6 [50]
Alpino-class frigate 1968 Italy 2,000 tons 28 knots 2 [45]
Alvand-class frigate 1968 Iran 1,110 tons 40 knots 4 [51]
Knox class 1969 US 3,011 tons 27 knots 46 [18]
Chikugo-class destroyer escort 1971 Japan 1,470 tons 25 knots 11 [43]

Surviving destroyer escorts

Four destroyer escorts are preserved as museum ships, while others remain in active service.

See also

Notes and references

This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.

Footnotes

  1. ↑ 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.

Source notes

  1. ↑ Blackman, pp. 393 & 394
  2. 1 2 3 Watts, pp. 225-239
  3. ↑ Potter & Nimitz, p. 550
  4. ↑ Cooney, pp. 6 & 7
  5. ↑ NAVPERS, pp. 32 & 35
  6. 1 2 Franklin 1999, p. 7.
  7. 1 2 Silverstone, pp. 153-157
  8. 1 2 Silverstone, pp. 157-163
  9. 1 2 Silverstone, pp. 164-167
  10. 1 2 Silverstone, pp. 167-170
  11. 1 2 Silverstone, pp. 163 & 164
  12. 1 2 Silverstone, pp. 170-175
  13. 1 2 Blackman, p. 458
  14. 1 2 Blackman, p. 457
  15. 1 2 Blackman, p. 456
  16. 1 2 Blackman, p. 455
  17. 1 2 Blackman, p. 452
  18. 1 2 Blackman, p. 453
  19. 1 2 Lenton 1998, pp. 198–199.
  20. ↑ Morison 1956, p. 34.
  21. ↑ Collingwood 1998, pp. 30–31.
  22. ↑ Franklin 1999, p. x.
  23. 1 2 DANFS: Hotham.
  24. ↑ Lenton 1974, p. 16.
  25. ↑ Lenton & Colledge, p. 225
  26. ↑ Silverstone, p. 246
  27. 1 2 Lenton & Colledge, p. 232
  28. ↑ Blackman, p. 114
  29. ↑ Blackman, p. 354
  30. ↑ Blackman, p. 44
  31. ↑ Blackman, p. 199
  32. ↑ Blackman, p. 353
  33. 1 2 Blackman, p. 113
  34. ↑ Blackman, p. 624
  35. ↑ Blackman, p. 356
  36. ↑ Blackman, p. 183
  37. ↑ Blackman, p. 355
  38. ↑ Blackman, p. 8
  39. 1 2 Blackman, p. 43
  40. ↑ Blackman, p. 351
  41. ↑ Blackman, p. 127
  42. ↑ Blackman, p. 21
  43. 1 2 Blackman, p. 198
  44. ↑ Blackman, p. 350
  45. 1 2 Blackman, p. 182
  46. ↑ Blackman, p. 79
  47. ↑ Blackman, p. 348
  48. ↑ Blackman, p. 240
  49. ↑ Blackman, p. 78
  50. ↑ Blackman, p. 229
  51. ↑ Blackman, p. 167

Bibliography

Online sources

Further reading

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