The modern Roayl Thai Navy operates two of the Rattanakosin-class guided-missile corvettes in HTMS Rattanakosin (FS-441) and HTMS Sukhothai (FS-442). Both were built by Tacoma Boat Building Company of the United States to the "PFMM Mk 16" standard and carry a mix of American and European systems and armament. The pair were built from the period spanning 1984 to 1986 and entered commissioned service in 1986. Both ships are in active service as of this writing (2018).
NOTE: This article covers the various qualities of HTMS Sukhothai (FS-442).
HTMS Sukhothai displaces 960 tons and has an overall (bow-to-stern) length of 76.8 meters, a beam (width) measuring 9.6 meters and a draught (height) down to 4.5 meters. The propulsion scheme involves 2 x German MTU 20V1163 TB83 marine diesel turbines developing a combined 16,000 horsepower and these are used to drive 2 x Shafts located under the stern section. The warship can make headway at speeds up to 24 knots when dashing and 18 knots when cruising. Aboard is a crew of 87 personnel made up of officers and sailors.
The warship is completed with the usual systems and sensors allowing it to take on a "multi-mission" mindset. This includes both surface-search and air-search radar as well as a complete fire control radar suite. A sonar system is installed at the bow for undersea detection of unseen enemy elements. The warship's profile involves a low-profile superstructure, running from the forecastle to the afterdeck, complete with slab-siding adding a stealth quality. The bow is slightly raised and the forecastle short. The bridge is set at the extreme forward-end of the superstructure with a commanding view out over the forecastle. The main mast, of an enclosed, pyramidal design, is integrated into the bridge section and clearly carries the WM 25/41 fire control radome installation. Aft of this, at midships, are the low-profile, tapered smoke funnel structures which give the vessel another stealth-like quality. The second mast, much shorter than the forward mast, is of an enclosed design and carried the DA05 air/surface-search radar aerial fit. This is set over the rear superstructure area.
The warship is classified as a corvette and its dimensional compactness does not allow it to carry helicopter launch and retrieval capabilities (in the form of a helideck and hangar). Its "guided-missile" classification also implies an armament scheme reliant on missile-minded weaponry.
Towards the bow are a pair of traversing turrets (in the "A" and "B" positions). The forward-most emplacement sports a single 76mm (3") OTO-Breda (Italian) deck gun with the secondary emplacement fielding a 40mm /70 caliber twin-gunned weapon system. For extreme close-in support, the warship relies on 2 x 20mm Oerklikon (Swiss) autocannons. Ranged airspace denial is through 8 x "Albatross" surface-to-air missiles fired from a single launcher found at the right aft side of the quarterdeck. The armament suite is rounded out by 2 x "Harpoon" (United States) anti-ship missile launchers in quad-launcher fittings (located at the afterend of the hull superstructure) as well as 2 x Triple-tubed torpedo launchers.