Destroyer escort

USS Evarts, an example of the Evarts subclass.
Class overview
Operators:	United States Navy  Royal Navy  Republic of China Navy  Free French Naval Forces  French Navy  Hellenic Navy  Marina Militare  Japan Maritime Self-Defense Force  Republic of Korea Navy  Philippine Navy  Portuguese Navy  Royal Netherlands Navy  Royal Thai Navy  National Navy of Uruguay
Subclasses:	Evarts (GMT) class Buckley (TE) class Cannon (DET) class Edsall (FMR) class Rudderow (TEV) class John C. Butler (WGT) class Dealey class Claud Jones class

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.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 (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.

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. 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).

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.