(8:55 a.m. EDT) -- Six months after one of the worst cruise ship disasters of recent times, salvage crews have begun preliminary operations to refloat Costa Concordia.
A barge has been positioned alongside the vessel, which lies mostly submerged on its starboard side atop a rocky reef off the Italian island of Giglio. Preparations for the refloat will begin with removal of objects from the ship's top deck, including the radar, waterslide and distinctive yellow Costa funnel (all seen in photo at right).
Two salvage companies, Titan Salvage, an American firm, and Italian-based Micoperi split a bid on the operation expected to cost more that $300 million and take nearly a year.
In what's being called an "unprecedented" effort, the Italo-American consortium will use pulling machines connected to a custom-built subsea platform to hoist the hull upright in one piece. The firms won the right to perform the work during a months-long bidding process.
The next step in the project is to stabilize the ship to prevent further slippage down the sloped seabed on which it rests. This will be achieved by attaching "tieback chains" from the submerged part of the ship (starboard side, closest to shore) to posts built nearby.
After Concordia is stabilized, the subsea platform will be built along the exposed port side and huge caissons, in essence steel boxes, will be welded onto the side of the ship. The caissons will be filled with water. "This gives the ship extra buoyancy," explained Mark Hoddinott, general manager of the International Salvage Union (Hoddinott previously worked for Titan). "Caissons have the effect of making the ship wider, and the water will add mass, which improves the 'turning moment' to bring it upright."
Pulling machines will then be connected to the subsea platform, and two cranes fixed to the platform will pull Concordia upright -- facilitated by the water-filled caissons. (The ship will still be flooded, so it won't float; instead it will rest on the platform.) When the ship is upright, caissons will be welded to the starboard side of the hull. The caissons on both sides will then be de-ballasted -- after treating and purifying the water to protect the marine environment -- and filled with air.
"This strategy has been used on a smaller scale by both the US and Royal Navy," added Hoddinott. "But no one has removed a ship of this size." Concordia is 950 feet long and weighs 44,612 metric tons (or nearly 100 million pounds), according to Titan-Micoperi.
Once upright and stable, the wreck will be towed to an Italian port and dealt with in accordance with the requirements of Italian authorities (The underwater platform and posts will also be removed from the site.) Gianni Onorato, Costa's president, told Cruise Critic in early May that the ship will ultimately be scrapped.
No details on the specific cost of the project have been officially released, but a Costa spokesman said the figure could exceed $300 million.
According to a statement released by Costa in May, the "one piece" approach -- rather than slicing the ship up and barging it off bit by bit -- will "minimize environmental impact, protect Giglio's economy and tourism industry, and maximize safety." After the ship is removed, the sea bottom will be cleaned and marine flora replanted.
While the project is ongoing, the operation base will be located on the mainland near Piombino, where equipment and materials will be stored. This will mitigate impact on the island's port activities and leave Giglio's hotels open for tourists during the peak summer season.
The news this week comes shortly after a joint announcement by the Mayor of Giglio and Costa for plans to have the 80-ton boulder that's wedged in the hull of the ship removed and turned into a monument to be displayed in Giglio harbour.
Costa Concordia foundered on January 13, 2012. At least 30 people died, and two remain unaccounted for.
--by Dan Askin, Senior Editor; updated by Jamey Bergman, Content Producer, U.K.
--Schematic photo appears courtesy of Titan-Micoperi.