Air bubbles released from a pipe on the seabed will be used to form a buffer curtain to protect the marine park from noise pollution during the salvage.
A giant yellow drill shatters into the rocky seabed next to the rusting Costa Concordia wreck as workers battle to pull off the biggest salvage operation of its kind in history.
Cranes tower over the luxury liner, which lies covered in seaweed where it capsized on Giglio island in January. A gaping hole where the swimming pool used to be reveals the ghostly depths of the ship's nine-story central atrium.
The disaster, which killed 32 people, left salvage teams facing the unprecedented challenge of removing a ship with a gross tonnage of 114,500 GT without spilling its rotting contents into the sea.
"It's the biggest ship recovery ever by quite some way," said Nick Sloane, salvage master for US company Titan, which won a bid for the project jointly with Italian offshore rig company Micoperi to right and float the Concordia. "The plan is based on a lot of assumptions made by our engineering teams. It's a thumbsuck, but an informed thumbsuck," the South African said with a grin, adding that he has a cigar ready to celebrate the day the ship floats.
One of the biggest risks is that the ship, which is grounded on two large outcrops close to the shore, will slip when righted and plunge into the depths. The plan is for 26 pillars to be driven into the seabed to support a series of underwater platforms as big as football fields for the ship to sit on.
Large metal tanks that can be filled with water will then be welded onto the sides of the ship to balance the giant wreckage while it is dragged into an upright position using two cranes as well as cables attached to the platforms. The largest of the tanks are as high as an 11-storey building and weigh 500-plus tons, and getting them lined up precisely on the frame is far from easy.
"There's never been anything like this. It's part salvage, part offshore operation," said Franco Porcellacchia from the ship's parent company Carnival.
Teams working late into the night this week at the operation's nerve center in a hotel on Giglio coordinated the arrival of 66 divers tasked with putting 17,500 tons of cement bags in a 50-metre gap between the ship and the seabed.