Search by air and sea continued on Tuesday for 30 crew members missing after HTMS Sukhothai sank in the Gulf of Thailand on Sunday night, the Royal Thai Fleet commander said.

Adm Adung Pan-iam said on Tuesday the navy “still hope that all 30 sailors are alive”.

“We will continue our search day by day until we find them," he said.

The commander said that the 30 missing men were sailors and marines assigned to the corvette HTMS Sukhothai. On Monday, 31 men were reported missing. One was later rescued from the sea by the frigate HTMS Kraburi off Prachuap Khiri Khan. He was unconscious, with a head injury, but kept alive by his buoyancy vest.

The corvette had left the Sattahip naval base in Chon Buri. A day later it faced what its commander described as the roughest sea he had seen in a decade, Adm Adung said.

The raging sea prevented the corvette returning to Sattahip. The captain decided to head for shelter in Bang Saphan district of Prachuap Khiri Khan on Sunday evening, but could not make it. The ship capsized and sank in the storm.

"The incident happened very fast. The port side listed first and life rafts could not be launched there. The starboard side faced the stormy sea and it was difficult to release life rafts," the commander of the Royal Thai Fleet said.

"The captain confirmed that he followed all procedures and did his best to handle the crisis and prevent the vessel from capsizing, until that could not be done and the ship had to be abandoned," he said.

Of the 106 people aboard HTMS Sukhothai, about 70 were navy sailors, along with about 30 marines and personnel from the Air and Coastal Defence Command, Adm Adung said.