Never before has such an enormous cruise ship been righted, and the crippled Concordia didn't budge for the first three hours after the operation began, engineer Sergio Girotto told reporters. But after some 6,000 tons of force were applied using a complex system of pulleys and counterweights, "we saw the detachment" from the reef thanks to undersea cameras, he said.
Images transmitted by robotic diving vehicles indicated that the submerged side of the hull had suffered "great deformation" from all its time on the granite seabed, battered by waves and compressed under the weight of the ship's 115,000 tons, Girotto said.
The initial operation to lift the Concordia from the reef moved the ship just 3 degrees toward vertical, leaving the vessel some 62 degrees shy of being pulled upright. While a seemingly small shift, the movement was significant enough to be visible: A few feet of slime-covered hull that had been underwater became visible above the waterline.
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So far, "rotation has gone according to predictions," and no appreciable pollution from inside the ship has spewed out, said Franco Gabrielli, chief of Italy's Civil Protection agency, which is overseeing the operation.
Giglio is part of a Tuscan archipelago in a marine sanctuary where dolphins romp and fish are plentiful.
The operation, known in nautical parlance as parbuckling, is a proven method to raise capsized vessels. The USS Oklahoma was parbuckled by the US military in 1943 after the Japanese attack on Pearl Harbor.
The operation involves engineers using remote controls to guide a synchronised leverage system of pulleys, counterweights and huge chains looped under the Concordia's carcass to delicately nudge the ship free from its rocky seabed and rotate it upright.