Seoul (AFP) - Chinese and South Korean salvage experts on Wednesday began an underwater survey of the sunken Sewol ferry -- the first step in the long, complex process of raising the 6,825-tonne vessel to the surface.
The passenger ship sank off the southwest coast in April 2014 with the loss of more than 300 lives, most of them children on a school trip.
Nine remain unaccounted for in the accident, which deeply traumatised the entire nation, and the families of those still missing had led a campaign for the ferry to be brought to the surface.
South Korean officials announced last month that a consortium led by China's state-run Shanghai Salvage had won the bid for the salvage operation.
A tugboat and a Chinese barge with a giant crane arrived several days ago at the site where the Sewol lies 40 meters (132 feet) down on the seabed.
Divers made exploratory dives Wednesday as an unmanned submersible was being prepared for launch from the barge, anchored some 20 kilometres (12.5 miles) off the southern island of Jindo, an official from the South Korean Ministry of Oceans and Fisheries told AFP by phone.
Nearly 150 people, including divers and technicians, are involved in the initial stage, which will involve taking extensive pictures of the sunken vessel over the next two months, the official said.
There are also plans to place a net around the Sewol to prevent any bodies still trapped inside from being lost in the salvage process.
Preparations will be halted in November for the winter, and the salvage operation proper will begin in March next year with a view to bringing the ship to the surface before July.
The recovery is expected to cost around 85 billion won ($72 million) and some have questioned whether the expense is merited, given the slim chance of finding any more bodies or uncovering any fresh evidence regarding the cause of the tragedy.
South Korean divers, working in dangerous conditions with strong currents and low visibility, recovered 295 bodies before abandoning the search in November last year.