Workers placed the first steel beam under the ancient sunken ship South China Sea No.1 on Tuesday, paving the way for the ship to be hoisted out of water in mid October, officials said.
Another 34 beams, each stretching 15 meters and weighing more than five tons, would be placed under the ship at a pace of one steam for each day afterwards, said Wang Renyi, an official with Guangzhou Salvage Bureau who is in charge of the salvage of the ship.
The beams were made airtight and hollow to be buoyant, Wang said. Two floating bags were tied on each end of one beam and start inflation when the beam goes under water to generate more buoyant force.
Salvage operations on the ship South China Sea No.1 produced during Southern Song Dynasty (1127-1279) started in May as a specially designed steel structure was lowered into the sea near Yangjiang, in south China's Guangdong Province.
The rectangular structure was pulled by a 900-ton tug to a position just above the ill-fated ship.
According to the salvage plan, the upper part of the steel structure will be brought out of the seawater together with the sunken ship, while the lower part will stay on the seabed forever.
Experts spent three years planning the salvage, considered to be a world first for underwater archaeology.
Archaeologists normally excavate the relics on the sunken boat first and then salvage the boat.
The salvage workers had planned to start placing beams under the ship on August 3. The job, however, was delayed by three typhoons, namely Pabuk, Sepat and Wutip.
The sunken ship was found accidentally in 1987 by Guangzhou Salvage Bureau and a British underwater salvage company. The first ancient vessel to be discovered on the "Marine Silk Road" in the South China Sea, it was named South China Sea No.1.
The ship is located some 30 nautical miles west of Hailing Island of Yangjiang City, and lies at a depth of more than 20 meters. About 30 meters long, the vessel is the largest Song Dynasty cargo ship ever discovered.
Archaeologists estimate that there are probably 60,000 to 80,000 relics on the sunken ship.
It is believed that a successful salvage of the sunken ship will offer important material evidence for restoring the "Silk Road on the Sea", and for the study of China's history in seafaring, ship-building and ceramics making.
Workers have cleared away 25 tons of silt around the sunken ship and have brought out of the seawater 390 cultural relic items. They include green glazed porcelain plates, tin pots and shadowy blue porcelain objects.