The early 1940s were not a good year for the French. After declaring war on Germany following its invasion of Poland in 1939, France soon found itself defeated and occupied by its Nazi neighbors. The new French government, headquartered in Vichy, found itself trying to keep its overseas empire together.
Its colonial possessions and their neighbors proved far more aggressive than the French had originally anticipated, leading to some strange but relatively quick altercations – one of which was the brief Franco-Thai War.
France and Thailand had negotiated border disputes between the Royal Thai government and its border with French Indochina for years before World War II and important agreements were reached. The Thai government, still not entirely satisfied with the outcome, found that the French government might be less willing to enforce these agreements now that it was occupied by the Axis.
They were wrong about that, but they were right that French assets abroad were greatly weakened by the occupation of France. When Japan, now an Axis partner, began building bases on French territory, the Thais sensed an opportunity to regain these lost border possessions.
The French outnumbered them on land, with only 50,000 men in the country to defend its borders. He decided his best bet would be to attack the Thai forces by sea, where his superior navy could do most of the fighting.
On paper, the forces seem equal. The French had a light cruiser and four avisos (light sloops) to oppose the three Thai coastal defense ships, a handful of gunboats and a much larger air force. The French were to attack Thai naval forces in support of the land offensive which would be taking place at the same time.
Intelligence overflights revealed that there was only one coastal defense vessel and one torpedo boat at Ko Chang, so the French decided to start there. When they arrived, there were actually two torpedo boats, but the French continued the attack anyway.
As sunrise approached, the French caught the Thai ships while their crews were still asleep. They succeeded in destroying both torpedo boats and a shore observation post, cutting off the communication capability of the coastal defenses.
A few minutes later, the HTMS Thonburi, a Thai coastal defense vessel, entered the area and engaged the French flotilla – the entire flotilla. As she entered the battle, a lucky shot from the French light cruiser Lamotte-Picquet hit Thonburi directly and killed her captain. The Thai ship kept fighting, but her volleys were inaccurate and her response times were much worse than before.
The Thai coastal ship soon found her turrets jammed or fully withdrawn and retreated into shallow water. The French, whose ships were much heavier, could not keep up, but the damage was done. The French finish it off with torpedoes.
Two hours after the start of the battle, the French began to return home. They were suddenly attacked by a large Thai air force which dropped tons of bombs around the ships but failed to send one home. After firing a barrage of anti-aircraft fire, the ships returned to Saigon.
The Battle of Ko Chang is probably the only good news for the French in the early years of World War II, and the only good news for the French Navy in particular. In the Mediterranean, the rest of Vichy’s naval power was either scuttled by itself or defeated by the British at Mers-el-Kebir and Dakar.
