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Chakri Naruebet (OHPC)
Aircraft Carrier

The major addition to the Royal Thai Fleet was the vertical/short take off and landing (VSTOL) carrier Chakri Naruebet (which means "The Great of the Chakri Dynasty"), built by Bazan-Ferrol of Spain, and delivered to the RTN in 1997. Although acquisition of its full complement of VSTOL aircraft and helicopters was substantially slowed by the cutbacks imposed on defense purchases, it did come with seven AV-8S and two TAV-8S Matador (Harrier) STOL attack aircraft [withdrawn in 2006]. Six new-build S-70B-7 Seahawk multi-mission helicopters were also on board.

Because of the ship's capabilities and size it the most auspicious ship of the Royal Thai Navy. But the lack of funding restricted its operations and as a result, it was not deployed to support the UN mission in East Timor. This Offshore Patrol Helicopter Carrier (OHPC) intends to undertake a wide range of missions such as disaster relief, environment protection, amphibious operations, patrolling of territorial waters and control of local air space, Search And Rescue coordination and Exclusive Economic Zone surveillance. Secondary role is air support for all maritime operations.

The 11,400-ton displacement ship was the first air-capable vessel to enter service in Southeast Asia. The RTN designation of offshore patrol helicopter carrier (OPHC) reflects the ship's chief peacetime roles of disaster relief, search and rescue, exclusion zone surveillance and environmental protection. However, the navy also acknowledges that the ship has potential as a regional sea control asset during times of crisis. Rivalry between the Royal Thai Marine Corps and the new Air and Coastal Defense Command (ACDC) is of national concern.

The carrier was used after the 2004 Indian Ocean tsunami as well as in rescue operations after flooding in Thailand in 2010 and 2011. On May 25, 2015 Thailand deployed the carrier in its waters to serve as a temporary medical and processing center for migrants found adrift. The move came as the United States offered to launch reconnaissance flights over the Bay of Bengal to locate any remaining vessels, with thousands of Bangladeshi and Myanmar boat people still believed to be stranded at sea.

Prime Minister Prayut Chan-O-Cha told reporters If any boats (with migrants) are found, the navy will lead it to this large navy vessel for assistance... [Thailand will] facilitate their passage to temporary shelters in Malaysia and Indonesia... If anyone is injured or sick, they can be treated at hospitals in Thailand but will face illegal entry charges it is up to them to decide.


Under the contract signed in July 1992, the Chakrinaruebet is being constructed at Bazan's El Ferrol yard in Spain. The carrier would cost an estimated US$257 million, or US$365 million if fully equipped with combat systems and armament.

The Chakrinaruebet was launched on 20 February 1996. Sea trials commenced in October/November 1996, and delivery toot place in March 1997. The carrier was tasked with warfare/flagship command and control, air support for amphibious operations and the Thai surface fleet, EEZ surveillance and protection, search and rescue, and disaster relief. It was based in the Gulf of Thailand. The RTN may later consider a second carrier to protect its maritime zones in the Andaman Sea.

Thailand's two Naresuan-class frigates, were expected to escort the carrier, are also fitted with CODOG systems.


With a design similar to that of the Spanish carrier Principe de Asturias, HTMS Chakri Naruebet was fitted with a 12 degree ski jump to enable the use of Harrier-style aircraft. The carrier has a full-load displacement of 11,485.5 tons. Its overall length is 182.6m; flight-deck waterline beam 22.5m, and full-load draft 6.12m. It can accommodate a crew complement of 600 (there are also apartments for the Thai royal family). The structure has altered little from the original plans of 1992, although the sponsons have been changed slightly, the deckhouse for 2D radar has not been installed, and the main deck crane has been moved to the starboard of the forward lift.

The carrier's maximum speed is 26.2 knots, with a cruise speed of 17.2 knots. Range is estimated to be 10,000 nautical miles at 12 knots. Two spade rudders and four hull stabilisers have been fitted.

US Navy standards of subdivision were followed, with 13 watertight bulkheads and three independent fire zones. Twin rudders provide good maneuverability. The twin shaft Combined Diesel or Gas Turbines (CODOG) each rated at 33,600 HP. The machinery is located in two compartments, and includes two GE LM-2500 gas turbines, two Bazan-MTU 16 1163 TAB83 diesel engines each with an output power of 6437 HP at 1200 rpm and two twin-reduction gearboxes. Two variable-pitch five-blade variable-pitch propellers are fitted.

Armament was planed to eventually consist of four Raytheon/General Dynamics Phalanx Close-In Weapon Systems and two 30mm naval guns. Phalanx is a 20mm/53-calibre six-barrel gun capable of firing 3,000 rounds/min to a target range of 1.5km. The ship will be fitted with one eight-cell Mk 41 vertical launch system (VLS) for the Sea Sparrow surface-to-air missile and three Matra BAe Dynamics Sadral six-cell launchers for the Mistral missile. The Sadral launcher is a stabilized turret containing six missiles and launch canisters. The turret is equipped with a television camera which can be fitted with an infra-red channel for target acquisition.

The ship is equipped with six multi-mission Sikorsky S-70B Seahawk helicopters. These were supplemented with six ex-Spanish Matador AV-8S (Harrier) short take-off/vertical landing (STOVL) aircraft (currently out of service).

Combat Systems

The original plans proposed an electronics fit including 2-D long-range and 3-D medium-range air-surveillance radars, a ten-console command-and-control system, hull-mounted sonar; an electronic-warfare system incorporating electronic support measures, jammers and countermeasures launchers; and armaments including vertical missile launchers, four close-in weapon systems and a pair of 25/30mm cannon mounts. However, the aircraft platform due for delivery in 1997 will only be fitted with basic electronic systems, but not with defensive weaponry, electronic warfare systems, sensors or decoys.

The systems provided include a Hughes AN/SPS-52C 3-D medium range air search radar, a Kelvin Hughes navigation and helicopter control radar, a Kelvin Hughes I-band navigation radar, a MX 1105 Transit/GPS Omega satellite navigation system, as well as an unspecified Tacan system and a simple communications fit. The command and control system is made up of a combat information centre with seven Inisel consoles and an auxiliary console. The center is based on the Tritan combat data system using Unisys UYK-3 and UYK-20 computers. If upgraded the C2 system will be served by 11 consoles.

Until the carrier is equipped with armor, sensor and combat systems, it will remain heavily dependent on escort vessels for defence. The Thai navy lacks submarines for escort duty (a US$800 million plan to buy three submarines was shelved in May 1995, probably for financial reasons). Consequently, the carrier will have to rely on surface escorts to defend it against surface and submarine attack, although the basic command system will enable it to orchestrate operations involving the air group.

While Bazan says that it does not know of plans to equip the carrier with combat systems and armaments, it is possible that the Thai government intends to install these after delivery. There has been speculation that the US may assist with equipment upgrades, possibly in collaboration with Bazan. Other factors suggest that plans have stalled because the funds are not available.

There is no doubt, however, that the Chakrinaruebet order is a naval procurement landmark that was likely to prompt future carrier owners such as China and Japan to consider their maritime options, and existing carrier-owners such as Brazil, Argentina and India to plan for replacements.

Sikorsky S-70B Seahawk

The Royal Thai Navy ordered six multi-mission Sikorsky S-70B Seahawk helicopters to be deployed from the Chakrinaruebet in 1997. Costing US$138 million, these helicopters are designed for use in an anti-submarine role. The Chakrinaruebet's 174.6m x 27.5m flight deck can accommodate five simultaneous helicopter take-off/landings; the hanger provides space for ten more medium helicopters. It is estimated that the carrier could carry a maximum of 18 helicopters and aircraft; and 100 tons of ammunition.

AV-8S Matador

The Thai government was expected to supplement the helicopter air group with up to ten short take-off/vertical landing (STOVL) aircraft. These would includeex-Spanish Matador AV-8Ss. The Chakrinaruebet's 174.6m x 27.5m flight deck terminates in a 12 degree ski-jump, the hanger provides space for Harrier-sized aircraft.

The Spanish AV-8S Matadors of 8 Escuadrilla soldiered on well into the mid-1990s, when they were replaced by a further delivery of EAV-8B+ aircraft. Upon retirement, the surviving nine aircraft passed to the Royal Thai Navy (RTN) for US$90 million, who were newcomers to both carrier aviation and the Harrier. The RTN ordered an aircraft carrier from the Spanish shipbuilder Bzan in 1992 with the selected design being based on the Principe de Asturias, albeit smaller and simpler. The resulting vessel was named HTMS Chakri Naruebet and was launched in 1996 and commissioned in 1997. The Harrier fleet, consisting of seven AV-8Ss and two TAV-8Ss was delivered to Thailand along with the carrier.

Due to the costs of operational deployment the carrier was rarely at sea and its Harrier jump-jets are almost all non-operational because of a shortage of spare parts (specifically engines). Thailand's AV-8S Matador (Harrier) accompanying jet fleet was withdrawn from service in 2006, leaving Bangkok with an aircraft carrier without aircraft.

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Page last modified: 30-10-2015 19:05:54 ZULU