BANGKOK — Rescuers are combing the Gulf of Thailand on the crucial second day of a search for 30 sailors who are still missing after a warship sank.

Survivors have been found after floating for hours, with some in an unconscious state, officials said.

The HTMAS Sukhotai carrying 105 crew went down late Sunday after becoming flooded during a storm.

Rescuers have saved 75 people so far, with boats and helicopters in an operation scouring the rough seas.

On Monday night, a Thai naval commander said life jackets and other flotational devices as well as the officers' training "allow us 48 hours to save their life."

"Therefore, [Tuesday] will be the highlight. We will try to do as much as we can to save them," Vice Admiral Pichai Lorchusakul said.

With a third of the crew still unaccounted for, the Thai navy and air force resumed the search on Tuesday with hundreds of officers on four naval ships as well as several helicopters deployed to scan a vast 50-square-kilometer (30 square miles) area.

Several sailors have already been found, injured and exhausted after spending many hours at sea.

"We found this guy holding a life buoy... he was floating in the water for 10 hours," Captain Krapich Korawee-Paparwit of the HTMS Kraburi told Reuters.

"He was still conscious, so we could take him out of the water safely. He has a minor wound on his head and sore eyes as he was exposed to seawater."

Another unidentified crew member said he had been in the water for several hours before he was rescued.

"The waves were quite high, about three meters when the ship sank," he said in a clip shared on local media. "I put on the life jacket and jumped. I swam for three hours."

Other sailors were found in a life raft after they jumped from the sinking vessel.

Pictures and footage shared by the navy on Twitter show dozens of survivors wrapped in blankets and being taken to hospital. Several were also taken off the rescue ships in stretchers.

The HTMS Sukhothai, a 76m-long corvette, had been on day two of a routine patrol east off south-eastern Thailand when it got caught in a storm on Sunday night.

The Thai navy said water flooded its hull and then the electricity room, cutting the power.

Dramatic pictures posted on the navy's Twitter account shows the vessel listing onto starboard side, before the vessel went under around 11:30 pm Sunday (04:30 GMT).

Other naval ships were immediately alerted and sent to assist, but only the HTMS Kraburi frigate reached the vessel before it sank, about 32km east of Bang Saphan in the Prachuap Khiri Khan province.

It's not yet known what caused the ship to flood, and why sailors were forced to jump into the water. The Thai navy said this was the first time it had lost a ship in such circumstances.

The warship had been commissioned in 1987 and built in the United States by a local shipbuilding company, said the US Naval Institute. — BBC