During his reign, King Chulalongkorn had the first modern fort built in Samut Prakan and named it "Chulachomklao Fort". At this fort, a great heroic event still in the memory of every Samut Prakan citizen took place in 1893 when France and Thailand had a dispute, France had their gunboats close the estuary of the Chao Phaya River and battle erupted there. A cannon from Chulachomklao Fort was shot to extensively damage the French gunboats, leading to a ceasefire between Thailand and France and negotiation on the integrity and liberty of Thai people.

After that incident King Chulalongkorn started developing and reinforcing the Thai navy's might, establishing Naval Academy. One of his sons, his Royal Highness Admiral Kromluang Chumphon Khet Udomsak, had devoted his life to the naval development and was later named, "Father of the Royal Thai Navy"