Spruance-class destroyer

The Spruance-class destroyer was developed by the United States to replace a large number of World War II-built Allen M. Sumner- and Gearing-class destroyers, and was the primary destroyer built for the U.S. Navy during the 1970s.

First commissioned in 1975, the class was designed with gas-turbine propulsion, all-digital weapons systems, automated 5-inch guns. Serving for three decades, the Spruance class was designed to escort a carrier group with a primary ASW mission, though in the 1990s 24 members of the class were upgraded with the Mark 41 Vertical Launching System (VLS) for the Tomahawk surface-to-surface missile. Rather than extend the life of the class, the navy accelerated its retirement. The last ship of the class was decommissioned in 2005, with most examples broken up or destroyed as targets.

Design
The class was designed for anti-submarine warfare (ASW) with point defense anti-aircraft warfare (AAW) missiles; upgrades provided anti-ship and land attack capabilities. The ships were initially controversial, especially among members of the United States Congress who believed that their unimposing looks, with only two guns and an ASROC or Armored Box Launcher (ABL) missile launcher per ship implied that the vessels were weak compared to Soviet or older US designs which had more visible guns or launchers for the Standard medium range missiles. Despite the criticism they were successful for their intended ASW roles.

The Spruances were comparable in size to cruisers (CG) under the U.S. Navy's hull classification symbol system.. Despite their "DD" designation indicating gun destroyers, their primary armament was missiles. However the Spruance class as designed carried anti-aircraft missiles only sufficient for point defense, compared to other American destroyers designated as DDG which were designed to provide anti-aircraft warfare screening to the fleet while also having surface-to-surface capabilities. A major update in the 1990s would add a Vertical Launch Missile System (VLS) for the Tomahawk surface-to-surface missile which effectively made the modernized vessels up to DDG standard, although this class still lacked the stealth and missile capabilities of later Aegis equipped cruisers and destroyers.

The "Spru-cans" were the first large U.S. Navy ships to use gas turbine propulsion; they had four General Electric LM2500 gas turbines to generate about 80,000 horsepower (60 MW). This configuration (developed in the 1960s by the Royal Navy and known as COmbined Gas And Gas, or COGAG) very successful and used on most subsequent U.S. warships. A slightly lengthened version of the hull was also used for the Ticonderoga-class cruisers. As of 2010, all US Navy surface combatants (except nuclear aircraft carriers and the LCS-1) use the LM2500 COGAG arrangement, usually with two such turbines per shaft.

The entire class of 30 ships was contracted on 23 June 1970 to the Litton-Ingalls shipyard in Pascagoula, Mississippi, under the Total Package Procurement concept originated by the Whiz Kids of Robert McNamara's Pentagon. The idea was to reap the benefits of mass construction, but labor and technical problems caused cost overruns and delayed construction. One additional ship, USS Hayler, was ordered on 29 September 1979. Hayler was originally planned as a DDH (Destroyer, Helicopter) design, which would carry more anti-submarine helicopters than the standard design of the Spruance class. Eventually this plan to build a DDH was scrapped and a slightly modified DD-963 class hull was put in commission. Four additional ships were built for the Iranian Navy with the Mark 26/Standard AAW missile system but were completed as Kidds for the U.S. Navy. The Kidds were nearly identical to the Spruances but they were more advanced general-purpose ships. It was once planned to build all of the Spruance class up to this standard, but it was too expensive. An air-capable mini V/STOL aircraft carrier with fighters and ASW helicopters based on the Spruance hull was seriously considered but not produced.

Upgrades
The Spruance design is modular in nature, allowing for easy installation of entire subsystems within the ship. Although originally designed for anti-submarine warfare, 24 ships of this class were upgraded with the installation of a 61 cell Vertical Launch Missile System (VLS) capable of launching Tomahawk missiles. The remaining seven ships not upgraded were decommissioned early. At least ten VLS ships, including Cushing, O'Bannon, and Thorn, had a 21 cell RIM-116 Rolling Airframe Missile launcher mounted on the starboard fantail.
 * David R. Ray tested the RAM system in the 1980s, but had the system removed after the tests.
 * Oldendorf was the test platform for the AN/SPQ-9B Anti-ship Missile Defense (ASMD) Firecontrol Radar to be outfitted on the San Antonio class amphibious transport dock. The AN/SPQ-9B is used to detect all known and projected sea skimming missiles.
 * Arthur W. Radford tested the Advanced Enclosed Mast/Sensor system which helped in the mast design of San Antonio class amphibious transport dock ships.
 * Merrill served as the Navy's test platform for the Tomahawk Cruise Missile Program receiving armored box launchers and test launching a Tomahawk 19 March 1980. Merrill carried two ABLs and an ASROC launcher into the 1990s until the ASROC launcher was removed.

Spruance-class destroyers fired 112 land attack Tomahawks during Operation Desert Storm.

Fate
The US Navy planned to replace its current destroyers and cruisers with the new Zumwalt class destroyer (DDG-1000) ships. In order to save $28 million a year the navy accelerated retirement of the ships, though they could have served to 2019 had they been maintained and updated. The last Spruance-class destroyer on active service, USS Cushing (DD-985), was decommissioned on 21 September 2005. It was then offered to the Pakistan Navy, but was sunk as a target 29 April 2009. Per the 2010 U.S. Defense budget, only three DDG-1000s are being built. The Arleigh Burke class is the navy's only operational class of destroyers.

Some Spruance destroyers were broken up, but rather than being preserved in storage like some older classes, the majority of the class finished their lives as targets. Most were deliberately sunk in various fleet exercises. One notable exception was the four ships of the Kidd class that were transferred to the Republic of China Navy (Taiwan). They are active and referred to as the Kee Lung class.

The USS Paul F. Foster (DD-964) replaced the USS Decatur (DD-936) in 2005 as the Self Defense Test Ship. It is a refurbished ship, operated by remote control which avoids the safety constraints and other problems associated with manned ships being targeted by or towing targets by live weapons. The prearranged attack is in practice aimed at a decoy barge pulled 150 feet behind the SDTS in case of damage.