Navy chief, Adm Choengchai Chomchoengpaet, has ordered the setting up of a committee to investigate the circumstances surrounding the sinking of HTMS Sukhothai.
A subcommittee will look into the cause of the sinking, including maintenance and ship operation issues, said navy spokesman Adm Pokkrong Monthatpali.
Another part of the investigation will look at what happened when the ship was abandoned and the ensuing rescue efforts to save the crew, he added.
He said the navy is still searching for the missing sailors from HTMS Sukhothai.
He said HTMS Naresuan had found a body at 9.51am yesterday in an area off the coast of Bang Saphan district in Prachuab Kiri Khan and Pratew district in Chumphon.
The body would undergo an identification process to confirm if the dead man is one of the missing crew members.
Of the 105 crew aboard HTMS Sukhothai, 76 were rescued while 18 others were found dead, said Adm Pokkrong, adding that 11 remained missing as of yesterday.
Of the 18 victims, seven have been formally identified while others are being identified via markings on their bodies.
It was reported yesterday that a body was found on a Songkhla beach near a village in Sathing Phra district wearing a shirt with "Royal Thai Navy" printed on it.
However, the man turned out to be a drowned fisherman, and was not a missing member of HTMS Sukhothai's crew, the Thailand Maritime Enforcement Command Centre Region 2 said.
Prime Minister Prayut Chan-o-cha expressed his condolences to the families of the victims and ordered the navy to keep searching until all the missing crew are found, Defence Ministry spokesman Gen Kongcheep Tantrawanich said.
Gen Prayut said the navy will provide assistance to the families of the dead crewmen and hold funeral services for them.
He also said that His Majesty the King had appointed Adm Choengchai as his representative to attend royally-sponsored funerals of the dead crew members.