The Costa Concordia is being raised using a technique, known as parbuckling, never before used on a ship of this size.
The technique, according to the project's website, involves stabilizing the ship; preparing a false bottom under the ship; and fixing watertight boxes — or caissons — to the side of the ship that is above water. Then, undersea platforms are built on which the ship will rest after rotation.
Rotating or “parbuckling” the ship may take days and is a delicate task. Cranes will be used to pull the ship upright, helped by the caissons that will be filled with water. Once the ship is upright, caissons will be fitted to the other side to help stabilize it.
A pneumatic system then will push the ship upwards, the caissons will be emptied and the ship refloated and towed to a port.
The operation to remove the Costa Concordia was 73% complete at the beginning of August, according to the project's website.
A technique intended to reduce the environmental effect of recovering the wreck of the Costa Concordia is boosting insurers' and reinsurers' costs, making the cruise ship disaster the costliest marine loss of all time.