How to Refloat a Capsized Liner

Discovery News/ Eric Niiler

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.

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.

Salvers also may decide to force air into its ballast tanks in order to blow out water that has leaked through a 165 foot gash along the side. The damage would likely be repaired only after workers cut away the jagged edges around the gash and weld steel plates to the hull. The entire operation can be modeled on computer programs that predict the kinds of stresses that the ship can handle.  Read More >>