Footage shows rescue teams onboard a police helicopter as they continue searching for missing Thai sailors from a sunken navy warship.

Eighteen military personnel have been confirmed dead and 11 are still missing after HTMS Sukothai sank some 20 nautical miles off the Bang Saphan district in Prachuap Khiri Khan province on December 18 evening.

Officials are focusing on Chumphon province, where they believe ocean currents and prevailing winds will have washed the remaining sailors.

The vessel was carrying 105 military personnel to a ceremonial event when it was battered by strong waves. Water entered its hull and splashed into the electrical system some 20 nautical miles off the Bang Saphan district in Prachuap Khiri Khan province on December 18 evening.

The leakage disrupted the vessel's controls and power supply leading to a blackout before the ship tilted 60 degrees to starboard and more water flooded in.

Bungling naval chiefs have since admitted that there were not enough life vests on the ship for all the people onboard.

Records show that HTMS Sukhothai was built by Tacoma Boatbuilding Company, in Tacoma, Washington. It was commissioned in 1987 and had been operational for almost 36 years with air defence, sea combat and anti-submarine capabilities.

Thailand is notorious for its corruption, cover-ups and disturbing disregard for health and safety.