South Korea says preliminary investigations suggest an external explosion caused the sinking of a warship near the maritime border with North Korea last month.
A giant floating crane has retrieved the wreckage of the 1200-tonne gunboat, which was split in two by the blast. Forty-six crew members were killed.
The bodies of 38 of them have been recovered earlier, but the rest remain unaccounted for.
The BBC reports the bow section of the vessel is due to be raised in about 10 days.
South Korean officials had previously suggested two possibilities for the explosion: the ship could have struck an old mine left over from the 1950-53 Korean War, or it could have been sunk by a torpedo fired by North Korea.
North Korea has made no official comment on the incident, which occurred on 26 March.