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 , three small torpedo boats (the ), two sloops and four submarines ordered from Japan in 1935. The Italian design resembled a smaller version of the torpedo boats building for the Italian Navy. They were long overall and between perpendiculars, with a beam of and a mean draught of . Displacement was standard and 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 , giving a  contract speed of , with "Trad" reaching a speed of at during sea trials. of oil was carried, giving a range of at . The ship's main armament was supplied by Vickers-Armstrongs, to be compatible with existing British-built ships in the Thai Navy. Three anti-aircraft guns were carried, backed up by a close-in armament of two cannon and four machine guns. Six 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 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. Service. The first two ships ( and ) 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 and four sloops, attacked a Thai force including the coast defence ship together with three "Trad"-class torpedo boats, "Trad", and 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 . Ships. Note: Construction and delivery dates vary between sources.