Last Updated 3:27 p.m. ET
GIGLIO ISLAND, Italy In an unprecedented maritime salvage operation, engineers on Monday gingerly wrestled the hull of the shipwrecked Costa Concordia off the Italian reef where the cruise ship has been stuck since January 2012.
But progress in pulling the heavily listing luxury liner to an upright position was slower than expected. Delays meant the delicate operation originally scheduled from dawn to dusk Monday was not expected to be completed before Tuesday morning.
"Things are going like they should, but on a timetable that is dragging out," Franco Gabrielli, head of Italy's Civil Protection Agency, said Monday evening.
Never before has such an enormous cruise ship been righted.
An early morning storm delayed the salvage command barge from getting into place for several hours. Later, some of the cables dragging the ship's hull upright went slack, forcing engineers to climb the hull to fix them.
The crippled Concordia wouldn't budge for some three hours after the operation to right it -- known in nautical parlance as "parbuckling" -- began at around 9:00 a.m. local time, engineer Sergio Girotto told reporters.
But after some 6,000 tons of force were applied -- using a complex system of pulleys and counterweights -- Girotto said "we saw the detachment" from the reef thanks to undersea cameras.
He said the cameras did not immediately reveal any sign of the two bodies that were never recovered from among the 32 people who died Jan. 13, 2012, when the Concordia slammed into a reef and toppled half-submerged on its side after coming too close to Giglio Island.
Images transmitted Monday by robotic diving vehicles indicated that the submerged side of the cruise ship's 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 goal is to raise the ship 65 degrees to a vertical position, for eventual towing. The initial operation to lift the Concordia from the reef moved the ship just 3 degrees toward vertical. While a seemingly small shift, the movement was significant enough to be visible: A few feet of slime-covered ship that had been underwater slowly became visible above the waterline.
The entire rotation was originally expected to last as long as 12 hours. But as evening approached, work was clearly falling behind schedule. Some seven hours after the rotation attempt began, the Concordia had moved upward only by a total of 10 degrees.
"It's taking longer than expected," Girotto said in a late afternoon briefing. "Even if it's 15 to 18 hours, we're OK with that. We are happy with the way things are going."
Officials stressed that so far no appreciable pollution from inside the ship had spewed out. Giglio is part of a Tuscan archipelago in a marine sanctuary where dolphins and fish are plentiful.
Parbuckling is a proven method to raise capsized vessels; it was used on the USS Oklahoma in 1943 after the Japanese attack on Pearl Harbor. But the 1,000-foot Concordia has been described as the largest cruise ship ever to capsize and subsequently require the complex rotation.
The Costa Concordia is around two-and-a-half times the size of the Titanic, and no one wants to see it split apart, reports CBS News' Sabina Castelfranco.
The operation has attracted crowds of tourists and media, waiting to see the ship lifted.
"From what I can see it's moving bit by bit, it's raised about a meter and half from the sea level," said one of the tourists gathered on the harbor wall to watch it slowly rise out of the water.
Few of the locals will ever forget the night the Costa Concordia struck rocks. There was a mad rush to provide assistance to the thousands fleeing the ship. The harsh reality that 32 people lost their lives in the disaster still haunts many of them.
Two bodies are still missing, and their families are hopeful they will now be found.
Since the tragedy, the people of Giglio have watched their island's port transform itself into a work-in-progress area for an unprecedented salvage operation.
A 500-member international team of engineers and mechanics has worked tirelessly for months with one goal in mind: removing the 114,500-ton ship firmly stuck to two outcrops of rock on the seabed.
But it's a hugely complex operation and not one that is without risks. It is those risks that most concern the locals at this time.
They have been assured that all calculations have been made and nothing has been left to chance, but these islanders are concerned. Everyone is aware there are still 237.5 cubic meters of polluted water inside the ship, which could cause significant environmental damage to Giglio's pristine waters.
Additional emergency vehicles have arrived on the island, and as extra precaution, inflatable pollution barriers and fishing nets have been put up around the wreck and along the shoreline, in an effort to hold back any debris or oil that will spew from the Concordia as she turns.
The green light was given to its rotation after it became clear the ship could not remain in its current position another winter.