Trad-class torpedo boat

The Trad class was a class of nine torpedo boats built for the Royal Thai Navy in the 1930s by the Italian shipbuilder Cantieri Riuniti dell'Adriatico. They entered service between 1935 and 1938. Two of the ships were sunk (and a third badly damaged by French warships at the Battle of Ko Chang in 1941, but the remaining seven ships had long careers, remaining in service until the 1970s.

Construction and design
In 1934, the Royal Thai Navy launched a major re-equipment programme, with orders split between Italy and Japan. In 1934, Thailand ordered nine torpedo boats (the Trad class) and two minelayers from the Italian shipyard Cantieri Riuniti dell'Adriatico (CRDA), with two coast defence ships (the Thonburi-class coastal defence ship, three small torpedo boats (the Kantan-class torpedo boat), two sloops and four submarines ordered from Japan in 1935.

The Italian design resembled a smaller version of the Spica-class torpedo boat torpedo boats building for the Italian Navy. They were 67.97 m long overall and 66.75 m between perpendiculars, with a beam of 6.4 m and a mean draught of 2.13 m. Displacement was 318 LT standard and 470 LT full load. Two Yarrow boilers supplied steam for two sets of Parsons geared steam turbines, which drove two propeller shafts. The machinery was rated at 9000 shp, giving a contract speed of 31 kn, with Trad reaching a speed of 32.54 kn at 10000 shp during sea trials. 102 LT of oil was carried, giving a range of 1700 nmi at 15 kn.

The ship's main armament was supplied by Vickers-Armstrongs, to be compatible with existing British-built ships in the Thai Navy. Three 3 in anti-aircraft guns were carried, backed up by a close-in armament of two 20 mm cannon and four machine guns. Six 18 in torpedo tubes were fitted, with two twin mounts on the ships' centerlines and two single tubes mounted forward at the break of the forecastle. Crew was 70 officers and other ranks. By 1971, the surviving ships' armament had been revised, with one of the 76 mm guns and the two single torpedo tubes removed from all of the class, and one of the twin torpedo tube mounts removed from Trad, Phuket and Chumporn. This allowed the addition of one or two 40 mm Bofors guns.

The ships were built at CRDA's Monfalcone shipyard, with the first two launched in 1935, with four more following in 1936 and the remaining three in 1937.

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Service
The first two ships (HTMS Trad (1935) and HTMS Phuket (1935)) arrived in Bangkok on 19 April 1936, with the next two (Pattani and Surasdra) reaching Thailand by the end of the year, and the remaining five commissioning in Italy in March 1937. In January 1941, Thailand attacked French Indochina in the Franco-Thai War. As a response to the Thai successes on land, on 17 January 1941 a French Navy force, consisting of the cruiser FRENCH CRUISER Lamotte-Picquet and four sloops, attacked a Thai force including the coast defence ship HTMS Thonburi together with three Trad-class torpedo boats, Trad, HTMS Cholburi (1937) and HTMS Songkla (1937) in the Battle of Ko Chang. Thonburi, Cholburi and Songkla were sunk, while Trad was badly damaged. The remaining ships stayed in service until the 1970s, with the last ship retiring in 1977. The Chumpohn would later become a museum ship and can be visited today while the Pattani and Surat were sunk as targets.

The wrecks of the Chonburi and Songkhla have been discovered, surveyed, and documented by the Royal Thai Navy but the documentary released is poor and does not show the state of the wrecks beyond that they are intact.

Ships
Note: Construction and delivery dates vary between sources.