Millimetre by agonizing millimetre, the Costa Concordia is grinding its way to vertical position in a delicate operation that has so far tilted the ship by 25 degrees but met with a technical glitch that has slowed the progress.
Early Tuesday morning, local time, the Italian salvage officials said the final phase of the so-called parbuckling effort is underway. The ship is now past its tipping point, meaning that gravity has taken over, allowing the ship to be lowered onto its subsea platform using the massive buoyancy tanks fitted to its port side.
The final phase is expected to be finished at 4 a.m., after which the ship will be resting on an undersea platform.
Earlier Monday evening, the officials said the technical problem had resulted in an hour of lost time. Workers had to intervene to prevent the loose ends of four cables from becoming tangled with others still in use and under enormous tension.
The glitch and the slow, but mostly steady, progress means the Costa Concordia's rotation was several hours behind the original estimate.
The rotation angle was reported at 3 degrees at 12:30 p.m. local time. From the shore, the rotation's progress could be measured as the paint that had been blackened by the sea became plainly visible. By 7:30 p.m., it appeared that the ship had been lifted by 5 or 6 metres.
"We don't see anything to worry about," Sergio Girotto, project manager for Microperi, the Italian nautical engineering firm, said in the afternoon.
While the rotation is going to plan, it started about three hours late Monday morning, owing to an overnight thunderstorm. It may not finish until midnight local time, depriving the residents of Giglio the chance to see the ship set upright before Tuesday morning.
Officials were optimistic that the salvage would succeed. But they would not say that the most dangerous hours of the effort were over. "The most dangerous are the first 12 hours," said Franco Gabrielli, the Italian government's Cost Concordia emergency commissioner, referring to the expected length of the salvage.
Mr. Gabrielli said there was no sign yet of two missing passengers thought to be trapped in a lifeboat under the starboard side of the hull. He said underwater robots circling the hull may locate the remains later today.
Environment officials and residents of Giglio, a small island 16 kilometres off the Tuscan coast, are relieved that the operation is going well, all the more so since the salvage team's engineers found "big deformations" in the starboard side of the hull. The damage suggested that the rotting ship, 290-metres long, was becoming weak and in danger of breaking up.
The salvage of the ship turned into a spectacle, with hundreds of islanders and journalists and a few tourists filling the port and the steep hill behind the ship to watch its progress. The ship lies just a few hundred metres beyond the port.
Leo Bartoli, 74, a retired stonemason whose house overlooks the ship, said he gets angry at the ship's former captain, Francesco Schettino, every time he ventures outdoors and peers over the ledge. "I think the captain should be in prison," he said. "I think this every day."
Mr. Schettino is on trail for involuntary manslaughter and abandoning the ship ahead of some of its passengers. The disaster killed 32 passengers and crew on the night of Jan. 13, 2012.
The release of gases from rotting organic material, such as the dozens of tonnes of meat and cooking oils that remain on the ship, is a potential problem. If the ship breaks apart in the rotation, the toxic sludge could pollute the island's pristine waters and create a foul smell. Officials said there was no sign of gas release by the late afternoon.
Unless the ship breaks apart under the pressure loads, it will come to rest on an artificial seabed of grout bags and steel platforms. The steel alone is the length of 1 ½ football fields. In total, almost 30,000 tonnes of steel was used to build all the components being used to rotate and refloat the ship, making it one of Italy's biggest engineering projects.