How to Refloat a Capsized Liner


- Authorities worry that rough weather may push the ship out to deeper water.

- Diesel fuel must be removed from the ship, a process that will take at least several weeks, before it will become buoyant.

- A series of chains and pulleys in a winching system called "parbuckling" may finally right the ship.

How do you turn over a 952-foot cruise ship that's capsized on a rocky shoreline?

Marine engineers around the world are speculating on the best way to refloat the Costa Concordia, an operation that will begin as soon as authorities account for all the missing passengers.The Italian ship with 4,200 passengers and crew ran aground Friday in 45 feet of water as it was passing the island of Giglio off the coast of Tuscany. As of Tuesday, 11 people had been killed and more than a dozen were still missing.

SCIENCE CHANNEL VIDEO: Abandoned on a Sinking Ship

Although the ship lies on its starboard side and is in shallow water just offshore, Italian coast guard authorities fear that worsening weather is pushing it into deeper water which could make the rescue and salvage operation more difficult. Italian environmental officials have also asked the ship's owner, Miami-based Carnival Cruise Cruise Lines, to come up with a plan to remove 2,000 metric tons of diesel fuel that remain in the hull of the stricken liner.

"Nobody wants a wreck removal where you have to chop it up," said Joe Farrell III, a marine salver and naval architect at Resolve Marine Group in Fort Lauderdale, Fla. "You want to take enough weight off it so it will float off the bottom. The thing is on its side. You'd need to roll it right side up and you would need a crazy amount of force to do that."

Farrell recently returned from Sri Lanka where he salvaged a group of four ships, and also rescued a stranded cruise ship in the Arctic Canadian waters last year. Once the diesel fuel is removed from the ship, a process that will take at least several weeks, it will become more buoyant.

Recommended for you