The Lend-lease Act was passed into law in the USA in March 1941 enabling the United Kingdom to procure merchant ships, warships, munitions and other war materiel from the USA, in order to help with the war effort. This enabled the UK to commission the USA 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 (DE) on January 25, 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.
Full size destroyers must be able to keep up with and exceed the speed of fast capital ships, typically needing better than 25-35 knot speeds (dependent upon the era and navy) and carrying torpedoes and a relatively smaller caliber of cannon to use against enemy ships, as well as anti-submarine detection equipment and weapons.
However, a destroyer escort need only be able to maneuver relative to a slow convoy (which in World War II would travel at 10 to 12 knots), defend itself against aircraft, and detect, chase down, and attack a submerged (3 to 6 knot speed) or surfaced (22 knot speed) submarine. These lower requirements greatly reduce the size, cost, and crew required for the destroyer escort. While fleet destroyers were still more effective for anti-submarine warfare, the destroyer escort outweighed this by being able to be built considerably faster and more economically. Destroyer escorts were also considerably more seaworthy than Corvettes.
Destroyer escorts were also useful for coastal anti-submarine and radar picket ship duty.
Some 95 Destroyer escorts were converted to APDs (High Speed Transports). This involved adding an extra deck which allowed space for about 10 officers and 150 men. The modern Littoral Combat Ship also adds transport and boat launching capabilities to a ship smaller than a destroyer. Two large davits were also installed, one on either side of the ship from which landing craft (LCVP) could be launched.
Destroyer escorts were not meant to fight against cruisers and battleships, but that is what happened in the Battle off Samar. While Admiral Halsey's main force of US carriers and battleships was pursuing the Japanese decoy carrier force, that left the landing ships and troops guarded by escort carriers and destroyer escorts. While the escort carriers launched their planes, destroyer escort ship Samuel B. Roberts of task group Taffy 3 joined other out-gunned destroyers in a counter-attack against Admiral Kurita's powerful force of Japanese cruisers and battleships.
With no armor, only two 5-inch guns and 3 Mark-15 torpedoes capable of punching a hole in enemy hulls, her crew lacked the weapons and training in tactics to compete with the much larger heavy cruiser Chokai. The Roberts dodged shellfire to fire a salvo of 3 torpedoes which struck the cruiser. The battle continued for an hour, and the Roberts fired over 600 5-inch shells, and hit the upper works with 40 mm Bofors and 20 mm anti-aircraft guns at close range. Chikuma's bridge was set afire and the number 3 gun turret was disabled. Chikuma scored two direct hits on the Roberts, which soon sank with 89 of her crew. After the battle the Roberts became known as "the destroyer escort that fought like a battleship". The Roberts was an instrumental part of a small task force of light ships that forced a much larger armoured battle force to turn away from American landing forces in Leyte Gulf, though at a high cost.
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. The DDG 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 the amount of tons). One example of this ambiguity are the Ticonderoga-class air defense ships, which are classified as cruiser even though they use the same hull as the Spruance class destroyer.
|Class Name||Lead Ship||Commissioned||Ships Built|
|Evarts class||USS Evarts (DE-5)||15 April 1943||72|
|Buckley class||USS Buckley (DE-51)||30 April 1943||102|
|Cannon class||USS Cannon (DE-99)||26 September 1943||72|
|Edsall class||USS Edsall (DE-129)||10 April 1943||85|
|Rudderow class||USS Rudderow (DE-224)||15 May 1944||22|
|John C. Butler 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|
The main design difference between the Royal Navy frigates and the US Navy destroyer escorts was that the British Buckley class had the forward torpedo tubes removed (the Evarts class was not designed to carry torpedo tubes As well, British frigates had the ice cream makers, the iced water fountains, the dishwashers, and laundries (in some ships) and the replacing of the primitive American two seat "thunder trough" toilets (which did not offer even so much as a simple canvas screen to spare blushes) with an enclosed water closet.