Destroyer escort (DE) was the United States Navy mid-20th-century classification for a warship designed with the endurance necessary to escort mid-ocean convoys of merchant marine ships.Blackman, pp. 393 & 394
Development of the destroyer escort was promoted by the British need in World War II for anti-submarine ships that could operate in open oceans at speeds of up to 20 knots. These "British Destroyer Escorts" were designed by the US for mass-production under Lend-Lease as a less expensive alternative to fleet destroyers.Potter & Nimitz, p. 550
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. Similar types of warships in other navies of the time included the 46 diesel powered Kaibōkan of the Imperial Japanese Navy, 10 Kriegsmarine F-class escort ships, 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 anti-aircraft capability, but remained smaller and slower than postwar destroyers.Cooney, pp. 6 & 7 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).NAVPERS, pp. 32 & 35
General description
Full-sized destroyers must be able to steam as fast or faster than cruisers and fast capital ships such as fleet carriers. This typically requires a speed of 28-40mph) (dependent upon the era and navy). They must carry torpedoes and a smaller caliber of naval guns to use against enemy ships, anti-aircraft guns, and antisubmarine detection equipment and weapons. While these requirements made the destroyer a fast all-around combatant, this made them too valuable to be relegated to convoy escort duties.
A destroyer escort needed only to be able to maneuver relative to a slow convoy (which in World War II would travel at ), 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. The slower speed of destroyer escorts was not a liability in this context as sonar was useless at speeds over .
As an alternative to geared steam-turbine propulsion found in sloops of similar purpose, size and speed (as well as full-sized destroyers and larger warships), many US destroyer escorts of the World War II 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 (produced on special precise machining tooling available in limited quantities, 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 war, many destroyer escorts were re-used as floating power stations for coastal cities in Latin America under programs funded by the World Bank.. ships were the exception to this and they used a geared diesel engine to drive the propellers directly. s used the typical boiler and geared turbine propulsion system.
Destroyer escorts were also useful for coastal antisubmarine 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, 36 more DEs were converted to DERs, serving as such until 1960–1965.Friedman, Destroyers, pp 230–232 Their mission was to extend the Distant Early Warning Line on both coasts, in conjunction with 16 s, which were converted Liberty ships.
During 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 (LCVPs) 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 (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.
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.
Alternatives Destroyer escorts were designed and built to naval construction standards, and as such could only be built at yards experienced with naval standards. The United States Maritime Commission created its S2-S2-AQ1 design – which was based on the British-designed River class – for much the same role but using civilian construction standards. These ships would be classed by the Navy as the Tacoma class frigates (PF).Friedman, Small Combatants These frigates had a greater range than the superficially similar destroyer escorts, but the US Navy viewed them as decidedly inferior in all other respects. The Tacoma class had a much larger turning circle than destroyer escorts, lacked sufficient ventilation for warm-weather operations (a reflection of their original British design and its emphasis on operations in the colder North Atlantic Ocean), were criticized as far too hot below decks, and, because of the mercantile style of their hulls, had far less resistance to underwater explosions than ships built to naval standards like the destroyer escorts.Gardiner, Robert, ed., Conway's All the World's Fighting Ships 1922–1946, New York: Mayflower Books, 1980, , pp. 148–149.
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 (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. 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 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 classes Class name Propulsion Guns Torpedoes Lead ship Commissioned Ships built Evarts (GMT)Silverstone, pp. 153–157 diesel - electric 3 × 3in/50 0 USS Evarts (DE-5) 15 April 1943 97 Buckley (TE)Silverstone, pp. 157–163 turbo - electric 3 × 3in/50 3 × 21in USS Buckley (DE-51) 30 April 1943 148 Cannon (DET)Silverstone, pp. 164–167 diesel - electric 3 × 3in/50 3 × 21in USS Cannon (DE-99) 26 September 1943 72 Edsall (FMR)Silverstone, pp. 167–170 geared diesel 3 × 3in/50 3 × 21in USS Edsall (DE-129) 10 April 1943 85 Rudderow (TEV)Silverstone, pp. 163 & 164 turbo - electric 2 × 5in/38 3 × 21in USS Rudderow (DE-224) 15 May 1944 22 John C. Butler (WGT)Silverstone, pp. 170–175 geared turbine 2 × 5in/38 3 × 21in USS John C. Butler (DE-339) 31 March 1944 83 DealeyBlackman, p. 458 geared turbine 4 × 3in/50 4 × 21in USS Dealey (DE-1006) 3 June 1954 13 Claud JonesBlackman, p. 457 diesel 2 × 3in/50 6 × 13in USS Claud Jones (DE-1033) 10 February 1959 4 BronsteinBlackman, p. 456 geared turbine 2 × 3in/50 Mk33,rapid-fire version using an auto-loading mechanism to insert the shell into the breech ASROC 6 × 13in USS Bronstein (DE-1037) 15 June 1963 2 GarciaBlackman, p. 455 geared turbine2 × 5in/38 USS Garcia (DE-1040) 21 December 1964 10 BrookeBlackman, p. 452 geared turbine1 × 5in/38 USS Brooke (DEG-1) 12 March 1966 6 KnoxBlackman, p. 453 geared turbine1 x 5in/54 USS Knox (DE-1052) 12 April 1969 46
World War II shipbuilding programs
total ships in the table: 507DEs + 56APDs
37 Buckleys listed here as Buckleys were converted to APDs after having been commissioned as destroyer escorts. All APDs listed in the table were completed as conversions. Captains were converted before commissioning as DEs.
Builder State Evarts + Captain Buckley + Captain (+Charles Lawrence APDs) Cannon Edsall Rudderow (+Crosley APDs) Butler total (laid down from) Feb 1942 Jul 1942 Oct 1942 Jun 1942 Jul 1943 Aug 1943 (launched until)Feb 1944May 1944Aug 1944Dec 1943Apr 1944Aug 1944 (commissioned from) Apr 1943 Apr 1943 May 1943 Apr 1943 Dec 1943 Dec 1943 (commissioned until) Aug 1944 Jul 1944 Dec 1944 Feb 1944 Sep 1944 Dec 1945 Consolidated Steel TX 12 (+6) 47 (+3) 34 93 Bethlehem(Fore River and Hingham) MA 27 + 46 14 (+23) 87 Bethlehem, San Francisco CA 12 12 Boston Navy Yard MA 21 + 31 10 62 Brown Shipbuilding TX 38 23 61 Federal Shipbuilding and Drydock Company NJ 36 16 52 Mare Island Navy Yard CA 31 31 Philadelphia Navy Yard PA 5 + 1 10 2 (+4) 18 Dravo Corporation DE, PA 3 (PA) 15 (DE) 18 Charleston Navy Yard SC 15 2 (+9) 17 Defoe Shipbuilding Company MI 13 4 (+11) 17 Western Pipe and Steel Company CA 12 12 Norfolk Navy YardVA 1010 Tampa Shipbuilding Company FL 9 9 Puget Sound Navy Yard WA 8 8