Sea Control Ship

The Sea Control Ship (SCS) was a small aircraft carrier developed and conceptualized by the United States Navy under Chief of Naval Operations Elmo Zumwalt during the 1970s. Currently the term refers to naval vessels that can perform similar duties. The SCS was intended as an escort vessel, providing air support for convoys. It was canceled after budgetary cuts to the US Navy.

The SCS was to be equipped with a mix of Rockwell XFV-12 fighter aircraft and anti-submarine warfare helicopters. It was tasked with carrying out anti-submarine warfare operations.

Concept
In the late 1960s, studies by US Navy studies identified a potential requirement for large scale convoy operations in the event of a war with the Soviet Union. In order to compensate for a shortage of escort ships, it was suggested that helicopters operating from small helicopter carriers could fill the gap. When Elmo Zumwalt became Chief of Naval Operations in 1970, he seized on the idea of small helicopter carriers as part of his "High-Low" plan in which large numbers of cheaper lower capability ships would be built to supplement existing expensive high capability ships. The proposed small carrier, which was named the Sea Control Ship (SCS), was required to provide continuous airborne cover of two anti-submarine and one airborne early warning helicopters, as well as carrying VSTOL fighters to stop Soviet long-range aircraft (like the Tupolev Tu-95 "Bear") from shadowing convoys and directing submarines and surface ships against them. This resulted in a requirement to carry 14 helicopters and three VSTOL fighters such as the AV-8 Harrier. It was hoped that production SCSs could be built for $100 million each, an eighth of the price of a full sized CVN.

The resultant design had a full load displacement of 13736 LT and an overall length of 610 ft. It was to be powered by two General Electric LM2500 gas turbines generating 45000 shp and driving a single shaft, which would propel the ship to a speed of 26 kt. Weaponry was to be limited, consisting of two Phalanx Close-in weapon systems to defend against anti-ship missiles.

Experimental Sea Control Ship
In 1971 the USS Guam (LPH-9) was chosen as a test vessel. Testing began on January 18, 1972. In 1974 she was deployed to the Atlantic Ocean as part of the US Marine Corps. The vessel was equipped with AV-8A Harrier STOVL fighters and Sea King ASW helicopters. The tests were completed in July 1974; the USS Guam resumed its role as an amphibious assault ship.

Similar and related ships
The SCSs were smaller than most fleet aircraft carriers, and the concept was seized upon by nations wanting cheap aircraft carriers. Spain's flagship, Principe de Asturias (R11), and her smaller cousin ship, Thailand's HTMS Chakri Naruebet, were based on the final US Navy blueprints for a dedicated sea control ship, but with the addition of a ski-jump ramp and follow a similar mission profile. As currently configured, the Italian aircraft carrier Giuseppe Garibaldi (551) would also fit under the SCS description. A STOVL flight deck equipped with Harriers for air cover was seriously considered in the 1970s for the SCS but in the end rejected by the US Navy and Congress.

The British began life separately from the Elmo Zumwalt SCS design and has its origins in a sketch design for a 6,000 ton, guided-missile armed, helicopter-carrying escort cruiser intended as a complement to the much larger (60,000 ton) CVA-01 design fleet aircraft carrier. The cancellation of CVA-01 in 1966 meant that the smaller cruiser would now have to provide the anti-submarine warfare (ASW) taskforce with command and control facilities. A 17,500 ton vessel was chosen with a "through-deck", nine Sea King helicopters and the missiles right forward. By 1970, the "through-deck" design had advanced into a Naval Staff Requirement for an 18,750 ton Through-Deck Command Cruisers (TDCC). In May 1975, the British Government authorised the maritime version of the Hawker Siddeley Harrier, which was successfully developed into the Sea Harrier. This meant that the design was reworked again to include a small complement of these VTOL aircraft. In order to launch a heavily-laden Harrier more efficiently by STOVL (short take-off vertical landing) from the comparatively short - 170 m - flight deck, a 'ski-jump' was developed.

The Soviet s had a similar mission, but were much bigger as they were effectively an SCS and a heavy missile cruiser combined into one hull. The Kiev class was equipped with twelve short ranged defensive Yakovlev Yak-38 STOL fighters and sixteen Kamov Ka-25 or Kamov Ka-27 ASW helicopters which operated from an angled flight deck. The forward deck was filled with eight large P-500 Bazalt surface-to-surface missiles for land and sea strike missions as well as torpedo launchers and strong layered missile and gun anti-aircraft defenses.

Ships with secondary SCS mission
Ships that can be used for secondary SCS missions include many modern amphibious carriers, such as the U.S. and  classes. All of these ships typically operate STOVL/VTOL fighter/attack aircraft and some have also operated as light carriers in both of the Persian Gulf operations after unloading and deploying the Marine ground forces equipment (e.g. tanks, armored vehicles, landing craft), troop, and cargo helicopters of their primary amphibious assault mission. The Spanish ship Juan Carlos I will also split its duties between amphibious assault and SCS/aircraft carrier work.

Falklands War
The only example of a conflict where a SCS-type ship played a large part was the Falklands War in 1982. Unable to acquire new full-size carriers due to political opposition, Britain had procured "through-deck cruisers" for her NATO contribution to keep sea lanes clear of Soviet submarines and patrol aircraft. In this mission they typically carried four to five BAE Sea Harriers and nine Sea Kings for anti-submarine warfare. When Argentina invaded the Falkland Islands, HMS Invincible (R05) and HMS Hermes (R12) (a conversion of a light fleet carrier to ASW carrier) were filled to capacity with RAF Harrier and RN Sea Harrier fighter aircraft to recover the islands. The Sea Harriers shot down 21 Argentine aircraft in air-to-air combat with no air-to-air losses, although two Sea Harriers were lost to ground fire and four to accidents. Both types of Harriers were also used for strike missions and support of the ground troops.