The cannons were officially fired for the first time in the "Rattanakosin Era Year 112 Incident" to protect Thailand's sovereignty from the French invasion. The event occurred at dusk on 13 July 1893, barely one month after the Chulachomklao Fort was completed. During the engagement, the Disappearing Guns joined six Royal Thai Navy ships in bombarding the French ships "Inconstant" and "Comete" that were attempting to sail up the Chao Phraya River to join the gunship "Lutin" that was already moored in Bangkok.