Destroyer escort

A destroyer escort (DE) is the classification for a smaller, lightly armed warship designed to be used to escort convoys of merchant marine ships, primarily of the United States Merchant Marine in World War II. Slower and less expensive than a fleet destroyer, destroy escorts were employed primarily for anti-submarine warfare, but also provided some protection against aircraft and smaller attack vessels. The US built roughly 457 destroyer escorts spread out over 8 classes. The Royal Navy deployed destroyer escorts of the Evarts subclass and of the Buckley subclass (with the torpedo tubes removed) and designating them as Captain-class frigates. The Royal Navy and Commonwealth forces' frigates had a similar role to American destroyer escorts.

Although destroyer escorts lacked the arms, armor and speed to attack fast armored cruisers and battleships, at the Battle off Samar, the task group Taffy 3 of escort carriers, destroyers and destroyer escorts were attacked by a superior Japanese fleet led by the giant battleship Yamato. The Butler-class destroyer escort Samuel B. Roberts became known as "the destroyer escort that fought like a battleship" as it inflicted damage from torpedoes and gunfire on much larger cruisers, and was an instrumental part of a small task force of light ships forcing a far superior enemy fleet to turn back.

Origins
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 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.

General description


Full size destroyers must be able to keep up with and exceed the speed of fast capital ships such as fleet carriers and cruisers, typically needing better than 25-35 knot speeds (dependent upon the era and navy) and carrying torpedoes and a smaller caliber of cannon to use against enemy ships, as well as anti-submarine detection equipment and weapons.

A destroyer escort only needed to be able to maneuver relative to a slow convoy (which in WW II would travel at 10 to 12 knots), defend against aircraft, detect, pursue and attack submarines. These lower requirements greatly reduce the size, cost, and crew required for the destroyer escort. While fleet destroyers were more effective for anti-submarine warfare, the destroyer escort outweighed this by being able to be built faster and cheaper. Destroyer escorts were also considerably more seaworthy than corvettes.

As an alternative to steam turbine propulsion found in full size destroyers and larger warships, many US destroyer escorts of the WWII period had diesel-electric or turbo-electric 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 optimum speed for the propellers. The current from the engine room can be used equally well for other purposes, and post-WWII many destroyer escorts were recycled as floating power stations for coastal cities in Latin America under programs funded by the World Bank.

Destroyer escorts were also useful for coastal anti-submarine and radar picket ship duty.

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 (LCVP) could be launched. The modern Littoral Combat Ship also adds transport and boat launching capabilities to a ship smaller than a destroyer.

Battle off Samar
Destroyer escorts were not meant to fight against cruisers and battleships, but that is what happened in the Battle off Samar, which was part of the Battle of Leyte Gulf, 23-26 October, 1944. While Admiral Halsey's main force of US carriers and battleships was pursuing the Japanese decoy carrier force, the task of guarding the landing ships and troops fell to escort carriers, destroyers and destroyer escorts. While the escort carriers launched their planes, the Butler-class destroyer escort ship Samuel B. Roberts of task group Taffy 3 joined other outgunned destroyers in a counter-attack against Admiral Kurita's powerful force of Japanese cruisers and battleships, including the Yamato.

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.

Postwar U.S. ship reclassification
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 displacement). One example of this ambiguity are the Ticonderoga-class air defense ships, which are classified as cruisers even though they use the same hull as the Spruance-class destroyers.


 * List of destroyer escorts of the United States Navy

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 of America, launched in 1942–1943 and delivered to the United Kingdom under the provisions of the Lend-Lease agreement (under which the United States of America supplied the United Kingdom and other Allied nations with materiel between 1941 and 1945), they were drawn from two sub-classes of the destroyer escort (originally British destroyer escort) classification: 32 from the Evarts sub-class and 46 from the Buckley sub-class. Upon reaching the UK the ships were substantially modified by the Royal Navy, making them distinct from the US Navy destroyer escort ships.

Captain-class frigates acted in the roles of convoy escorts, anti-submarine 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 post-war period, all of the surviving Captain-class frigates except one (HMS Hotham) were returned to the US Navy before the end of 1947 in order to reduce the amount payable under the provisions of the Lend-Lease agreement; the last Captain-class 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 (F-1), ex-Cronin (DE-107)
 * FFL Sénégalais (F-2), ex-Corbestier (DE-106)
 * FFL Somali (F-3), ex-Somali (DE-111)
 * FFL Hova (F-4), ex-Hova (DE-110)
 * FFL Marocain (F-5), ex-Marocain (DE-109)
 * FFL Tunisien (F-6), ex-Crosley (DE-108)

Mutual Defense Assistance Program - Post WWII
Under the Mutual Defense Assistance Program (MDAP) the Destroyer Escorts leased to the Free French were permanently transferred to the French Navy. In addition the following navies also acquired Destroyer Escorts:

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

 * DE-168, DE-169

Philippine Navy

 * DE-168, DE-169, DE-170, DE-770, DE-771, DE-251, DE-637

Portuguese Navy

 * DE-1032, DE-1039, DE-1042, DE-1046

Republic of Korea Navy

 * DE-770, DE-771

Royal Navy
DE-574

Royal Netherlands 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,

Notes and references

 * Footnotes


 * Source notes


 * Bibliography




 * Online sources