Two south koreans were still missing yesterday after the speedboat they were riding in crashed into a fishing trawler off Phi Phi Island on Sunday.
The victims were among dozens of tourists on the boat, whose driver faces charges related to reckless driving.
"I was bending down to pick up some stuff for just a half a minute when my boat suddenly banged into a fishing trawler. I tried to swerve my boat to the side but it got caught in fishing net slings," boat driver Surat Mas-osot said yesterday.
There were 43 people on board his boat - mostly foreign tourists.
Go Min Woo, 31, and An Sun Yong, 28, are the missing South Koreans.
Rear Admiral Somchai na Pangchang, chief of staff of the 3rd Royal Thai Fleet, said a helicopter was deployed to help with the search of some 120 square miles.
The Marine Police Division's Sub-Division 8 and volunteers have also joined the search operation.
"We will continue the search until we locate the missing victims," Pol Lt-Colonel Panya Chaichana of the sub-division said. All other passengers were rescued and taken ashore on Sunday. Most sustained injuries, with many suffering head injuries and broken bones.
Phi Phi is part of Krabi province. Muang Krabi Police superintendent Colonel Pruettipong Nuchanart said the accident took place about 10km off the island.
"We have already interrogated the boat driver. Now our investigators will seek information from the victims, who are still receiving treatment at hospitals," he said.
Harbour Department director general Chula Sukmanop said his agency planned to make boat operators strictly require all passengers to wear life vests.
"For example, boat staff should make it clear that their boat won't leave a pier unless all passengers wear life vests first," he said.