Destroyer escort
Destroyer escort was the United States Navy mid-20th-century classification for a 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 in 1975. From circa 1954 until 1975 new-build US Navy ships designated as destroyer escorts 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. 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. 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.
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 . 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, 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 than fleet destroyers. Their much slower speed was not a liability in this context, since sonar was useless at speeds over.
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 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.
Destroyer escorts were also useful for coastal antisubmarine and radar picket ship duty. During The Second World War, seven destroyer escorts were converted to radar picket destroyer escorts, 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 s, which were converted Liberty ships.
During The Second World War, some 95 destroyer escorts were converted by the US to high-speed transports. 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 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, 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. The BDE designation was retained by the first six destroyer escorts transferred to the United Kingdom ; 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.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 declared ocean escorts as frigates. 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. and the littoral combat ship were the main ship types planned in this area. However, by 2017 the Navy had reversed course, and put out a Request For Proposals for a new frigate class, temporarily designated FFG. One major problem with ship classification is whether to base it on a ship's role, or on its size. One example of this ambiguity is the air-defense ship class, which is classified as cruiser, though it uses the same hull as the s.Vietnam War
During the Vietnam War, the Republic of Vietnam Navy received two s from the United States.US Navy destroyer escort class overview
''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, they were drawn from two subclasses of the destroyer escort classification: 32 from the Evarts subclass and 46 from the Buckley subclass. 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, antisubmarine 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 postwar period, all of the surviving Captain-class frigates except one 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.
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
- FFL Algérien, ex-Cronin
- FFL Sénégalais, ex-Corbestier
- FFL Somali, ex-Somali
- FFL Hova, ex-Hova
- FFL Marocain, ex-Marocain
- FFL Tunisien, ex-Crosley
Mutual Defense Assistance Program - Post WWII
Republic of China Navy (Taiwan)
French Navy
Hellenic Navy
Italian Navy
Japanese Maritime Self-Defense Force
Philippine Navy
Portuguese Navy
Republic of Korea Navy
Royal Navy
DE-574Royal Netherlands Navy
Royal Thai Navy
National Navy of Uruguay
Comparison with contemporary frigates
The table below compares destroyer escorts and frigates designed for similar missions.| Name | Date | Nation | Displacement | Speed | Number built | Notes |
| 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 | |
| 1943 | US | 1,430 tons | 20 knots | 96 | ||
| Type B kaibōkan | 1943 | Japan | 940 tons | 19 knots | 37 | |
| 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 | |
| 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 'Blackwood' frigate | 1955 | UK | 1,180 tons | 24 knots | 15 | "second-rate" anti-submarine warfare frigates. Cheaper to produce than Type 12. |
| 1955 | Canada | 2,263 tons | 28 knots | 7 | anti-submarine | |
| Type B | 1956 | Japan | 1,070 tons | 25 knots | 2 | diesel |
| Type 12 'Whitby' 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 'Salisbury' frigate | 1957 | UK | 2,170 tons | 24 knots | 4 | aircraft direction |
| Canopo-class frigate | 1957 | Italy | 1,807 tons | 26 knots | 4 | |
| Type 41 'Leopard' frigate | 1957 | UK | 2,300 tons | 24 knots | 7 | anti-aircraft escort for convoys |
| Azopardo-class frigate | 1957 | Argentina | 1,160 tons | 20 knots | 2 | |
| 1958 | Canada | 2,366 tons | 28 knots | 7 | anti-submarine | |
| Claud Jones class | 1959 | US | 1,450 tons | 22 knots | 4 | |
| Type 12M 'Rothesay' frigate | 1960 | UK | 2,380 tons | 30 knots | 12 | ."Modified" Type 12. Anti-submarine |
| 1961 | Germany | 2,100 tons | 30 knots | 6 | fast | |
| 1961 | Australia | 2,100 tons | 30 knots | 6 | Originally designated as anti-submarine frigates, later re-designated as destroyer escorts. | |
| 1961 | Japan | 1,490 tons | 25 knots | 4 | ||
| Type 81 'Tribal' frigate | 1961 | UK | 2,300 tons | 28 knots | 7 | general purpose |
| 1961 | Italy | 1,410 tons | 26 knots | 4 | ||
| 1962 | France | 1,750 tons | 25 knots | 13 | dual purpose | |
| 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 'Leander' frigate | 1963 | UK | 2,450 tons | 30 knots | 26 | "Improved" Type 12. General purpose. |
| Bronstein class | 1963 | US | 2,360 tons | 26 knots | 2 | |
| Garcia class | 1964 | US | 2,620 tons | 27 knots | 10 | |
| 1966 | Norway | 1,450 tons | 25 knots | 5 | ||
| Brooke class | 1966 | US | 2,640 tons | 27 knots | 6 | guided missile |
| 1966 | Denmark | 2,030 tons | 28 knots | 2 | fast | |
| 1967 | Netherlands | 2,200 tons | 28 knots | 6 | ||
| 1968 | Italy | 2,000 tons | 28 knots | 2 | ||
| 1968 | Iran | 1,110 tons | 40 knots | 4 | ||
| Knox class | 1969 | US | 3,011 tons | 27 knots | 46 | |
| 1971 | Japan | 1,470 tons | 25 knots | 11 |
Surviving destroyer escorts
Five destroyer escorts are preserved as museum ships, while others remain in active service.- The is preserved in Galveston, Texas.
- The is preserved in Albany, New York.
- The BNS Bauru, formerly is preserved in Rio de Janeiro, Brazil.
- The modified, ARC Cordoba, formerly is preserved in Tocancipa, Colombia.
- The , formerly, was recently decommissioned by the Philippine Navy and will be preserved as a museum ship at Sangley Point.
- The HTMS Pin Klao, formerly, is active in the Royal Thai Navy as a training ship. She is the last operational World War II destroyer escort in any navy.
- The Japanese Maritime Self-Defense Force operates six s.
Footnotes