USS Gearing (DD-710)
|Name:||Gearing class destroyer|
Bethlehem Steel, Fore River Shipyard
|Operators:|| United States
Republic of China Navy (Taiwan)
Republic of Korea Navy
|Preceded by:||Allen M. Sumner-class destroyer|
|Succeeded by:||Mitscher-class destroyer|
|General characteristics as originally built|
|Displacement:||2,616 tons standard; 3,460 tons full load|
|Length:||390.5 ft (119.0 m)|
|Beam:||40.9 ft (12.5 m)|
|Draught:||14.3 ft (4.4 m)|
|Propulsion:||2 shaft; General Electric steam turbines; 4 boilers; 60,000 shp|
|Speed:||36.8 knots (68.2 km/h)|
|Range:||4,500 nmi (8,330 km) at 20 knots (37 km/h)|
The Gearing class of destroyers originated near the end of World War II when the United States Navy required more range (fuel) and anti-aircraft capabilities from its Allen M. Sumner-class destroyers. It managed that by adding 14 ft (4.3 m) to the length in the midsection.
The first of these modified Sumner-class destroyers was Gearing (DD-710).
In the late 1950s forty-four of the Gearing-class destroyers underwent extensive modernization overhauls, known as FRAM I, which was designed to shift them from more of an AA platform to an anti-submarine warfare platform.
The FRAM MK I program was designed primarily for the Gearing-class destroyers. This upgrade includes rebuilding the ship's superstructure, engines, electronic systems, radar, sonar, and weapons. The aft twin 5" guns were removed. Upgraded systems include SQS-23 sonar, SPS-10 surface search radar, 2 x triple Mk 32 torpedo launchers, 8-cell ASROC box launcher, and QH-50C DASH ASW drone helicopter, with its own landing pad and hangar. 
The Gyrodyne QH-50C DASH was an unmanned anti-submarine helicopter, controlled remotely from the ship. The drone could carry 2 x MK.44 homing ASW torpedoes. During this era the ASROC system had an effective range of only 5 nautical miles (9 km), but the DASH drone allowed the ship to deploy ASW attack to sonar contacts as far as 22 nautical miles (41 km) away. 
The FRAM MK II program was designed primarily for the Sumner-class destroyers, but were used to upgrade the Gearing class as well. This upgrade program includes life-extension refurbishment, a new radar system, Mk. 32 torpedo, DASH ASW drone, and most importantly, a new variable depth sonar (VDS).
After the Gearing class ships were retired from USN service, many were sold abroad, including over a dozen to the ROCN (Republic of China Navy) in Taiwan. The ROCN upgraded these ships under the Wu Chin I, II, and III programs and commissioned them as the Chao Yang class. The last batch of 7 Chao Yang-class destroyers were retired in early 2000s. 
Under the Wu Chin upgrade program, the old twin 5" mounts were removed and replaced with 4 x Hsiung Feng II SSM, 10 x SM-1 (box launchers), 1 x 8-cell ASROC, 1 x 76 mm gun, 2 x 40 mm/70 AA, 1 x 20 mm Phalanx CIWS and 2 x triple 12.75" torpedo tubes. The DASH ASW drones were not acquired, but hangar facilities aboard those ships that had them were later be used to accommodate ASW version of Hughes MD500 helicopters.
After the Chao Yang destroyers were decommissioned, the SM-1 launch boxes were moved to other ROCN ships to improve their anti-air capability.