HTMS Chakri Naruebet

HTMS Chakri Naruebet (Thai จักรีนฤเบศร, meaning "In honour of the Chakri Dynasty" ) is the flagship of the Royal Thai Navy (RTN), and Thailand's first and only aircraft carrier. Based on the Spanish Navy's Principe de Asturias design and constructed by Spanish shipbuilder Bazán, Chakri Naruebet was ordered in 1992, launched in 1996, and commissioned into the RTN in 1997.

The aircraft carrier is designed to operate an air group of V/STOL fighter aircraft and helicopters, and is fitted with a ski-jump. Initial intentions were to operate a mixed air group of Matador V/STOL aircraft and S-70B Seahawk helicopters. However, by 1999, only one Matador was operational, and the entire V/STOL fleet was removed from service in 2006. Although Chakri Naruebet was intended for patrols and force projection in Thai waters, a lack of funding brought on by the 1997 Asian Financial Crisis means that the carrier has spent much of her career docked at the Sattahip naval base.

Chakri Naruebet has been deployed on several disaster relief operations, including in the aftermath of the 2004 Indian Ocean earthquake and tsunami, and in response to separate flooding incidents in late 2010 and early 2011. Outside of disaster relief, the carrier's few other departures from port are for a single training day per month, and transportation of the Royal Family of Thailand, leading to claims by some naval commentators that the ship is merely an oversized royal yacht.

Design
When Typhoon Gay hit Thailand in 1989, the Royal Thai Navy, as the main unit responsible for search and rescue missions, found that its ships and aircraft were unable to withstand the rough weather at sea. Moreover, the Royal Thai Navy needed a new, high-technology ship to modernize its fleet. The original plan was to acquire a 7,800 ton vessel from Bremer Vulcan, but the Thai government cancelled the contract on 22 July 1991. A new contract for a larger warship to be constructed at Bazán's shipyard in Ferrol, Spain, and was signed by the Thai and Spanish governments on 27 March 1992. The proposed vessel was based on the design of the Spanish Navy aircraft carrier Principe de Asturias, which in turn was based on the United States Navy's Sea Control Ship concept. The design is formally referred to as an "Offshore Patrol Helicopter Carrier".

Chakri Naruebet is the smallest aircraft carrier in operation in the world. She displaces 11,486 tons at full load. The carrier is 164.1 m long between perpendiculars, and 182.65 m overall. She is 22.5 m wide at the waterline, with a maximum beam of 30.5 m, and a draught of 6.12 m. The warship has a ship's company of 62 officers, 393 sailors, and 146 aircrew. Up to 675 personnel can be transported; commonly soldiers of the Royal Thai Marine Corps.

Chakri Naruebet is propelled by a combined diesel or gas (CODOG) system. Each of the two, five-bladed propellers is connected to a Bazán-MTU 16V1163 TB83 diesel engine (providing 5600 bhp, used for cruising speed), and a General Electric LM2500 gas turbine (providing 22125 shp, used to reach top speed for short periods). Chakri Naruebet has a maximum speed of 25.5 kn, although she can only reach 17.2 kn with the diesels alone. She has a maximum range of 10000 nmi with a constant speed of 12 kn, and 7150 nmi at 16.5 kn.

Armament and aircraft
Chakri Naruebet is fitted with two 0.5-inch machine guns, and three Matra Sadral sextuple surface-to-air missile launchers firing Mistral missiles. The missile launchers were installed in 2001. The vessel is also fitted for but not with an 8-cell Mark 41 Vertical launch system for Sea Sparrow missiles, and four Phalanx close-in weapon systems.

The carrier was designed to operate an air group of up to six AV-8S Matador V/STOL aircraft, plus four to six S-70B Seahawk helicopters. Chakri Naruebet is also capable of carrying up to fourteen additional helicopters; a mix of Sikorsky Sea King, Sikorsky S-76, and CH-47 Chinook. There is only enough hangar space for ten aircraft.

The Matador is a first generation export version of the Hawker Siddeley Harrier, acquired secondhand from the Spanish Navy in 1997. The nine Spanish aircraft (seven standard version plus two TAV-8S trainer aircraft) were refurbished by Construcciones Aeronáuticas SA firm before delivery. By 1999, only one aircraft was operational, and the RTN was looking for other first-generation Harriers to cannibalize for spares. In 2003, the navy attempted to acquire several second-generation,ex-Royal Navy Sea Harrier FA2 aircraft from British Aerospace, but the deal did not go ahead. The inoperative Matadors were finally eliminated from service lists in 2006. Thailand was the last remaining government using first generation Harrier airframes.

The flight deck measures 174.6 by. A 12° ski-jump assists V/STOL aircraft to take off. There are two aircraft lifts, each capable of lifting 20 tons.

Sensors and countermeasures
The sensor suite of Chakri Narebet consists of a Hughes SPS-52C air search radar operating on the E/F band, and two Kelvin-Hughes 1007 navigational radars. There are provisions to install an SPS-64 surface search radar and a hull-mounted sonar, but neither has been fitted as of 2008. Fire control facilities are also yet to be fitted.

The carrier is equipped with four SRBOC decoy launchers, and an SLQ-25 towed decoy.

In April 2012 Saab won a contract to upgrade Chakri Naruebet's command and control systems. This will include fitting a 9LV Mk4 command and control system to the ship as well as a Sea Giraffe AMB radar and improved datalinks.

Construction
Work on the Thai carrier commenced in October 1993, although it was not until 12 July 1994 that the hull was laid down. Chakri Naruebet was launched on 20 January 1996 by Queen Sirikit.

Sea trials were conducted from October 1996 to January 1997, the latter part of which was in coordination with the Spanish Navy. This was followed by aviation trials at Rota, Spain. The carrier was handed over on 27 March 1997, when she was commissioned into the RTN. She arrived in Thai waters at the start of August 1997, and formally entered service on 10 August.

Chakri Naruebet cost US$336 million to build.

Role and operational history
Chakri Naruebet is the first aircraft carrier to be operated by a Southeast Asian nation. She is assigned to the Third Naval Area Command, and her intended duties include operational support of the RTN's amphibious warfare forces, patrols and force projection around Thailand's coastline and economic exclusion zone, disaster relief and humanitarian missions, and search-and-rescue operations. However, at the time the carrier entered service, the 1997 Asian Financial Crisis prevented the necessary funding to operate the ship from being available. Consequently, Chakri Naruebet is usually only operational for a single day per month for training, with the rest of the time spent alongside as a "part-time tourist attraction". The ship rarely leaves the proximity of the Sattahip naval base, and when she does, it is usually to transport and host the Royal Family of Thailand. Naval commentators consider Chakri Naruebet to be less an aircraft carrier and more the world's most expensive royal yacht, while the Thai media have nicknamed the ship "Thai-tanic", and consider her to be a white elephant.

Between 4 and 7 November 1997, Chakri Naruebet participated in disaster relief operations following the passage of Tropical Storm Linda across the Gulf of Thailand and the Kra Isthmus. The carrier's main task was to search for and assist any fishing vessels affected by the storm.

Flooding in the Songkhla Province resulted in the carrier's mobilisation in late November 2000. Chakri Naruebet was anchored at an island marina off Songkhla, and used as a base for helicopters and small boats transporting food, supplies, and wounded.

In January 2003, anti-Thai riots were sparked in Phnom Penh by incorrect news reports of a claim by a Thai actress that the Angkor Wat temple complex belonged to Thailand, not Cambodia. Chakri Naruebet was sent to help with any evacuation of Thai citizens from Cambodia.

Following an undersea earthquake in the Indian Ocean, tsunamis struck multiple regions around the Indian Ocean, including the Andaman Sea coast of Thailand. The personnel of Chakri Naruebet were part of a 760-strong response by the Thai military to the disaster. This task force was involved in search-and-rescue around Phuket and the Phi Phi Islands, treatment of wounded and handling of dead, and repair work to schools and government facilities.

During the August 2005 filming of Rescue Dawn, a dramatized biographical film of US Navy pilot Dieter Dengler and his capture during the Vietnam War, the flight deck of Chakri Naruebet was used to represent the carrier USS Ranger (CV-61).

In November 2010, the ship was involved in flood relief operations following the 2010 Thai floods; anchored off Songkhla Province, relief supplies and food were airlifted to people in the region, while hospital patients were evacuated by the ship's helicopters. Chakri Naruebet was sent to Koh Tao in late March during the 2011 Southern Thailand floods, as the heavy storms causing the flooding had isolated the island, requiring the evacuation of tourists and local citizens.