The heavily damaged Sri Ayudhya listing before it sank on 1 July 1951
On 29 June 1951, in a coup attempt known as the Manhattan Rebellion, a group of junior naval officers held Thailand's Prime Minister Plaek Phibunsongkhram (Phibun) at gunpoint during a boat-transfer ceremony at Ratchaworadit Pier on the Chao Phraya River in Bangkok. Phibun was taken aboard the HTMS Sri Ayudhya and held hostage. General stations were called, and the ship began to make way downstream towards the Naval Ordnance Department in Bang Na. However, the coup plotters failed to secure the opening of the Memorial Bridge, and the ship thus could not continue. Fighting quickly ensued, and the naval units that sided with the rebels became heavily outnumbered by the army, police and air forces, who were loyal to the government. Fighting subsided during the night but resumed and intensified early the next morning. Sri Ayudhya joined the fight, but its engines were soon disabled and the ship became dead in the water in front of Wichaiprasit Fort. It was heavily fired upon from the eastern bank by guns and mortars, and, by afternoon, was also bombarded by AT-6 trainer planes. Heavy fires broke out, and the order was given to abandon ship. Phibun had to swim ashore along with the sailors, but was uninjured. The fires continued throughout the night and into the next day, when fighting ceased. The heavily damaged Sri Ayudhya finally sank in the night of 1 July.
The wreck of Sri Ayudhya was later salvaged for scrap, as it had become a navigational hazard. The ship was officially struck from the naval register on 8 October 1959 in Ministerial Order 350/21315.