Preceded by John C. Butler class Built 1952–1957 | Succeeded by Claud Jones class In commission 1954–1994 | |
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Operators United States Navy
National Navy of Uruguay
Colombian National Navy Subclasses Oslo class
Admiral Pereira da Silva class | ||
The Dealey-class destroyer escorts were the first post-World War II escort ships built for the United States Navy.
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Slightly faster and larger than the escort destroyers they succeeded, the Dealey class were fitted with twin-mounted 3-inch guns, ASW rockets, a depth charge rack and 6 depth charge launchers. There were later modernisations that removed the ASW rockets and the depth charges in favor of nuclear-capable anti-submarine rocket launchers and torpedo mounts which fired lighter homing torpedoes. A large SQS 23 sonar was refitted in a bow sonar dome and most of the class were also fitted with a hangar and landing pad for DASH drone helicopters to deliver MK 44 and Mk 46 torpedoes. The drone helicopters proved very unreliable and their failure contributed to the relatively short life of the class.
They were decommissioned in 1972 and 1973 in favor of the Knox-class frigate. Dealey and Hartley were sold at surplus to other countries in 1972, with the remainder of the class being sold for scrap.
Development and design
In the late 1940s, the US Navy developed a requirement for a replacement for the PC-461-class submarine chaser in the coastal convoy escort and patrol roles. The existing submarine chasers were considered too small to carry the required anti-submarine weapons and sensors, and too slow to catch modern submarines, with a ship the size of existing destroyer escort required. The ships would need to be cheap and quick to build, as large numbers would be required in the event of a war. By 1950, the requirement had changed to an "Ocean Escort" with a speed of at least 25 knots (46 km/h; 29 mph) at full load and an endurance of 6,000 nautical miles (11,000 km; 6,900 mi) at 12 knots (22 km/h; 14 mph). An ahead-throwing anti-submarine weapons, at first planned to be the Mark 17, a large, trainable Hedgehog anti-submarine spigot mortar.
The final design, SCB-71, or the Dealey or DE-1006-class, was 315 feet (96.0 m) long overall and 308 feet (93.9 m) at the waterline, with a beam of 36 feet 8 inches (11.18 m) and a draft of 11 feet 10 inches (3.61 m). Displacement was 1,314 long tons (1,335 t) light and 1,877 long tons (1,907 t) full load. 2 Foster-Wheeler boilers fed steam to a geared steam turbine, which drove a single propeller shaft. The machinery was rated at 20,000 shaft horsepower (15,000 kW) which gave a design speed of 27 knots (50 km/h; 31 mph). A single-shaft machinery layout was chosen to ease mass production, avoiding potential bottlenecks in gear-cutting which had delayed production of wartime Destroyer Escorts.
As built, the ships had a gun armament of two twin 3 inch (76 mm)/50 calibre guns, mounted fore and aft. The Mark 17 Hedgehog was cancelled before the ships where built, so in its place two British Squid anti-submarine mortars were fitted ahead of the ship's bridge in Dealy, with a RUR-4 Weapon Alpha anti-submarine rocket launcher fitted in the remaining ships of the class. Launchers for anti-submarine torpedoes were fitted, and depth charge throwers were fitted on the ships' fantail. Sensors included the SPS-6 air-search radar and the SQS-4 low-frequency sonar.
The prototype ship, Dealey, was built under the Fiscal year (FY) 1952 shipbuilding program, with two ordered in both the FY 1953 and 1954 programs and eight in the 1955 program. Production was stopped at 13 because the Dealey-class was considered too expensive at $12 million for mass production. This resulted in the smaller, diesel-powered Claud Jones-class being built. The Dealey design formed the basis for the Norwegian Oslo-class and Portuguese Admiral Pereira da Silva-class frigates.
Modifications
All of the class except Dealey, Cromwell and Courtney were upgraded in the 1960s by adding facilities for the DASH drone helicopter, with a hangar and helicopter deck replacing the aft 3-inch gun mount and the longer-ranged SQS-23 sonar replaced the SQS-4. The three unmodified ships were fitted with a Variable Depth Sonar (VDS). All ships had their Squid or Weapon Alpha launchers removed late in their US Navy career, while Mark 32 torpedo tubes for Mark 44 or Mark 46 anti-submarine torpedoes were fitted.