This is how they got the Costa Concordia — twice the size of the Titanic — back to port


The refloated wreck of the Costa Concordia cruise liner is towed to the Italian port of Genoa on July 27, 2014.



Two and a half years after the Costa Concordia crashed off the coast of Giglio, Italy and killed 32 passengers, the cruise ship has made it to its final resting place: a dockyard in Genoa where it will be broken down for parts.

The salvage operation, which has been described as one of the largest in history, has been ongoing since a few weeks after the ship ran aground on Jan. 13, 2012. It's taken hundreds of workers — more than 600 from 29 nations at the operation's peak — to get the Costa Concordia ready for its final voyage. So how did they get an ocean liner that weighs more than 114,000 tonnes and measures 951 feet in length floating again?

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The first step in the process, which is called parbuckling, was stabilizing the wreck so it wouldn't fall further into the water. To do this, the crews wedged submarine anchor blocks in between the right side of the boat, which was submerged, and the coast. Then divers positioned cement-filled bags to level off the sea floor, and six platforms were installed to create a resting place for the ship once it was rotated to an upright position. (Several platforms were also erected to the left of the ship.)

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Once the platforms were in place, a crane was used to affix 15 sponsons — or metal air chambers that help with both stability and buoyancy — to the left side of the ship, which is more than double the size of the Titanic. At this point, the crews were ready to begin one of the most delicate parts of the operation: rotating the vessel. That was accomplished by tightening a series of cables attached to the platforms and caissons welded to the side of the ship. A misstep here could further damage the Costa Concordia's hull, which would make it more difficult to get the ship to Genoa.

With the ship upright, the crew attached 15 more sponsons to the right side. Once the the excess water was drained and air was pumped into the sponsons, the boat gained enough buoyancy to lift itself off the platforms by several feet.

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Fourteen boats then guided the Costa Concordia from the crash site to Genoa, a roughly 200-nautical mile journey that wound its way through ecologically sensitive areas. Two tug boats pulled the ship from the front, while two backup tugboats followed behind. A number of boats in the convoy monitored the damaged cruiseliner for oil spills and other potential environmental issues. (The Costa Concordia's fuel was drained shortly after the crash, but authorities didn't want to take any chances.) In the end, the mangled hull stayed relatively in tact despite concerns it would not be able to withstand the waves during the voyage. 

Even though the Costa Concordia has left the crash site, that doesn't mean the work for salvage crews is done. Workers will be cleaning the sea bottom and replanting marine flora to mitigate the environmental impact of the disaster.

The ship's owner, Costa Crociere, which is a subsidiary of Carnival Corp., will spend more than $2 billion for the salvage operation, according to company officials.