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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. From circa 1954 until 1975 new-build US Navy ships designated as destroyer escorts (DE) were called ocean escorts. Destroyer escorts, frigates, and kaibōkan were mass-produced for World War II as a less expensive antisubmarine warfare alternative to fleet destroyers.[3] Other similar warships include the 10 Kriegsmarine escort ships of the F-class and the two Amiral Murgescu-class vessels of the Romanian Navy.

Postwar destroyer escorts and frigates were larger than those produced during wartime, with increased antiaircraft capability, but remained smaller and slower than postwar 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

Full-sized 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 antisubmarine detection equipment and weapons.

A destroyer escort need

Postwar destroyer escorts and frigates were larger than those produced during wartime, with increased antiaircraft capability, but remained smaller and slower than postwar 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]

Full-sized 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 antisubmarine 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 antisubmarine 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).

As an alternative to steam-turbine propulsion found in full-sized destroyers and larger warships, many US destroyer escorts of The Second World War period had diesel-electric or turboelectric 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 optimal speed for the propellers. The current from the engine room can be used equally well for other purposes, and after The Second World War, many destroyer escorts were re-used as floating power stations for coastal cities in Latin America under programs funded by the World Bank.[citation needed]

Destroyer escorts were also useful for coastal antisubmarine and radar picket ship duty. During The Second World War, 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, 12 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 16 Guardian-class radar picket ships, which were converted Liberty ships.

During The Second World War, 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 (LCVPs) could be launched.[citation needed]

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, 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 antisubmarine 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 escorts 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 antisubmarine 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, new-build 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. To remedy this problem, the 1975 ship reclassification dec

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 antisubmarine 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).

As an alternative to steam-turbine propulsion found in full-sized destroyers and larger warships, many US destroyer escorts of The Second World War period had diesel-electric or turboelectric 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 optimal speed for the propellers. The current from the engine room can be used equally well for other purposes, and after The Second World War, many destroyer escorts were re-used as floating power stations for coastal cities in Latin America under programs funded by the World Bank.[citation needed]

Destroyer escorts were also useful for coastal antisubmarine and radar picket ship duty. During The Second World War, 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, 12 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 16 Guardian-class radar picket ships, which were converted Liberty ships.

During The Second World War, 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 (LCVPs) could be launched.[citation needed]

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, 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 antisubmarine 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 escorts 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 antisubmarine 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

When the United States entered the war, and found they also required an antisubmarine 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.

After World War II, new-build 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. To remedy this problem, the 1975 ship reclassification declared ocean escorts (and by extension, destroyer escorts) as frigates (FF). This brought the USN's nomenclature more in line with NATO, and made comparing ship types with the Soviet Union easier. As of 2006, no plans existed for future frigates for the US Navy. USS Zumwalt and the littoral combat ship (LCS) were the main ship types planned in this area. However, by 2017 the Navy had reversed course, and put out a Request For Proposals (RFP) for a new frigate class, temporarily designated FFG(X). 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 is the Ticonderoga-class air-defense ship class, which is classified as cruiser, though it uses the same hull as the Spruance-class destroyers.

Vietnam War

During the Vietnam War, the Republic of Vietnam

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

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 (MDAP).

List of Free French destroyer escorts

Mutual Defense Assistance Program - Post WWII

Under the MDAP the destroyer escorts leased to the Free French were permanently transferred to the French Navy. In addition, the following navies also acquired DEs:

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

Captain-class frigates acted in the roles of convoy escorts, antisubmarine 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 postwar period, all of the surviving Captain-class frigates except one (HMS Hotham) were returned to the US Navy before the end of 1947 to reduce the amount payable under the provisions of the Lend-Lease agreement; the last such frigate was returned to United States custody in March 1956.[23][24]

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 (MDAP).

List of Free French destroyer escorts

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

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.

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

Five 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. ^ a b c Watts, pp. 225-239
  3. ^ Potter & Nimitz, p. 550
  4. ^ Cooney, pp. 6 & 7
  5. ^ NAVPERS, pp. 32 & 35
  6. ^ a b Franklin 1999, p. 7.
  7. ^ a b Silverstone, pp. 153-157
  8. ^ a b Silverstone, pp. 157-163
  9. ^ a b Silverstone, pp. 164-167
  10. ^ a b Silverstone, pp. 167-170
  11. ^ a b Silverstone, pp. 163 & 164
  12. ^ a b Silverstone, pp. 170-175
  13. ^ a b Blackman, p. 458
  14. ^ a b Blackman, p. 457
  15. ^ a b Blackman, p. 456
  16. ^ a b Blackman, p. 455
  17. ^ a b Blackman, p. 452
  18. ^ a b Blackman, p. 453
  19. ^ a b Lenton 1998, pp. 198–199.
  20. ^ Morison 1956, p. 34.
  21. ^ Collingwood 1998, pp. 30–31.
  22. ^ Franklin 1999, p. x.
  23. ^ a b DANFS: Hotham.
  24. ^ Lenton 1974, p. 16.
  25. ^ Lenton & Colledge, p. 225
  26. ^ Silverstone, p. 246
  27. ^ a b Lenton & Colledge, p. 232
  28. ^ 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. ^ a b c Watts, pp. 225-239
    3. ^ Potter & Nimitz, p. 550
    4. ^ Cooney, pp. 6 & 7
    5. ^ NAVPERS, pp. 32 & 35
    6. ^ a b Franklin 1999, p. 7.
    7. ^ a b Silverstone, pp. 153-157
    8. ^ a b Silverstone, pp. 157-163
    9. ^ a b Silverstone, pp. 164-167
    10. ^ a b Silverstone, pp. 167-170
    11. ^ a b Silverstone, pp. 163 & 164
    12. ^ a b Silverstone, pp. 170-175
    13. ^ a b Blackman, p. 458
    14. ^ a b Blackman, p. 457
    15. ^ a b Blackman, p. 456
    16. ^ a b Blackman, p. 455
    17. ^ a b Blackman, p. 452
    18. ^ a
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