Salvage experts plan to use water-filled cisterns to weigh down the above-sea side of the cruise liner capsized off the Italian coast — part of an effort to turn the massive vessel upright so that it can towed for demolition early next year. One official on Friday called the operation's magnitude "unprecedented."

The Costa Concordia, which was carrying some 4,200 people, struck a jagged reef the night of Jan. 13 when it veered too close to the coast of tiny Giglio island. Gashed on one side, the ship began listing badly and eventually came to rest on its side on the rocky seabed just off the Tuscan shore. The accident killed 32 people.

Titan Salvage, a company based in Pompano Beach, Florida, won the bid to remove the Concordia's wreckage, which now lies in pristine waters.

Capt. Richard Habib, Titan Salvage's managing director, said the goal is to "use brains, (and) not as much brawn" to remove the Concordia without having it slip into much deeper water. He said the biggest challenge in the operation is to "roll the vessel upright on a platform and to safely float" it away to a port yet to be selected by Italian officials.

"The magnitude of the job ... is something unprecedented," Habib told reporters at a news conference.

Officials from Costa Crociere, the Italian company which operated the cruise ship, Titan Salvage and the Italian marine contractor Micoperi, which specializes in underwater construction and engineering, described the strategy to remove the Concordia at the news conference Friday.

The plan involves constructing an underwater platform and attaching empty cisterns to the above-water side of the ship. Then the cisterns will be filled with water, and two cranes attached to the platform will be used to pull the ship upright. Once upright, the ship will have cisterns attached to the other side. Then all the cisterns will be emptied of water before being filled with air to help the ship rise higher in the water and free itself of the seabed. Once it's properly afloat, it can then be towed to the seaport for demolition.

Habib said the ship would weigh some 45,000 tons without the water-filled cisterns. The goal is to have the ship upright by the start of winter and to start towing in early 2013, he said.

Experts at the news conference said some holes in the ship will have to be repaired before towing to make sure the vessel can float. The gash caused by the collision with the reef is dozens of meters (yards) long, but there also are several holes that were blasted into the wreckage so that divers could swim into submerged parts to search for bodies.

While nothing similar on such a scale has been tried before, Habib said, "we think our plan is going to work." He declined to say if there was a "Plan B" if the strategy fails. Authorities have expressed worry that the ship, in stormy seas, might slip off its seabed perch and slip into much deeper waters, making an intact salvage virtually impossible.

The Mediterranean waters near Giglio are teeming with fish, dolphins and other sea life. So far no pollution has been reported near Giglio, where many depend on fishing and tourism for their livelihoods.

The bodies of two victims of the disaster have yet to be located. Franco Gabrielli, the government official in charge of search and salvage operations, said that finding those two corpses has become "sort of an obsession for the searchers," and it's possible they may be recovered during the salvage operation.

The Italian captain of the Concordia is under house arrest while prosecutors investigate him for possible manslaughter and abandoning ship while the evacuation was still underway. Prosecutors contend that the captain steered the ship dangerously close to the island in a publicity stunt, while the captain insists the reef didn't appear on navigational charts.