Once the hole is patched, Farrell said that airbags could be placed under the hull to help stabilize the ship. They may not be enough to right-size it. That would be done using a series of chains and pulleys in a winching system called "parbuckling."Special marine chains made with 90-pound, 18-inch links are wrapped around the ship and then pulled around a pivot point or "deadman" that is anchored either into the sea bed or onshore. A winch then slowly pulls the ship back over.
"You're talking 5,000 to 6,000 tons of force," Farrell said. "It's got to be one of the biggest operations ever."
Marine salvage operators from Seattle to Greece are already eyeing the prize of repairing and refloating the massive Costa Conordia, which contains four swimming pools, five restaurants, 13 bars and a casino.
Some experts say the trend of ever-bigger cruise ships pose a danger on the high seas. It's not just the size of the ship, but the number of people on board, according to James Herbert, a spokesman for the International Salvage Union, a London-based trade group representing salvage operators. "Evacuating those passengers and handling them safety far out to sea is a matter of considerable concern," he said.