The Battle of Ko Chang took place on 17 January 1941 during the Franco-Thai War in which a flotilla of French warships attacked a smaller force of Thai vessels, including a coastal defence ship. The battle resulted in a tactical victory by the French Navy over the Royal Thai Navy although the strategic result is disputed. The Japanese intervened diplomatically and mediated a ceasefire. In the end, two Thai ships were sunk and one was heavily damaged. Within a month of the engagement, the French and the Thais negotiated a peace which ended the war. Background Situation The Franco-Thai War was going quite poorly for the French land forces, who were ill-equipped to deal with the larger Thai Army. The French Governor General of Indochina and Commander-in-Chief Naval Forces, Admiral Jean Decoux, decided Indochina's best chance at stopping the incursions would be attempt a naval attack on the Thailand's fleet and coastal cities. This would clear the way for bombardment missions to support a counter-offensive along the Cambodian frontier. Thai Navy Although comparatively small, the Royal Thai Navy had been modernized with the recent acquisition of vessels from both Japan and Italy. The major units of the fleet included two Japanese-built armored coast defence vessels, which displaced and carried 8-inch (203 mm) guns, two older British-built armored gunboats with 6-inch (152 mm) guns, 12 torpedo boats, and four submarines. In addition, the Royal Thai Air Force had on its rosters over 140 aircraft, including relatively modern Mitsubishi Ki-30 (Allied reporting name "Ann") light bombers, which saw extensive service against the French during the war. These aircraft were quite capable of disrupting any French naval operation which might be mounted. Other less capable aircraft in the Thai inventory included P-36 Hawk fighters, 70 Chance-Vought O2U-2 Corsair biplanes, six Martin B-10 bombers, and several Avro 504 trainers. French Navy Admiral Jean Decoux formed a small squadron called the Groupe Occasionnel (ad hoc group) on 9 December 1940 at Cam Ranh Bay, north of Saigon. In command he placed Capitaine de Vaisseau Régis Bérenger. The squadron consisted of: the light cruiser : a light cruiser built in 1923. The ship was fast but poorly armored. the modern avisos and . Those ships were especially designed for colonial service and could embark a company of infantry. They were very lightly armed and without armor. the older avisos Tahure and Marne. There was no air