Costa Concordia salvage

Step-by-step guide to the refloating and salvaging operation

Everything you wanted to know about the salvage of Costa Concordia but were afraid to ask, from infra-red sensors for oil detection to quick response dive teams

The wreck of the Costa Concordia cruise ship during an operation to refloat the liner  Photo: AFP/Getty

By Nick Squires, Giglio

10:52AM BST 14 Jul 2014

Refloating the Costa Concordia – the most challenging salvage ever attempted on a ship of this size.

The final cost of salvaging and removing the cruise ship is likely to be $1.2 billion.

This is how the operation will unfold –

Salvage master Nick Sloane in the control room aboard the wreck of the Costa Concordia cruise ship (AFP/Getty)

Phase 1

At the start of the operation on Monday the cruise liner was resting on giant steel platforms – in effect an artificial sea bed – to a depth of 100ft.

On the first day, the ship will be raised about six feet up off the platforms, in an operation expected to last up to eight hours.

Tug boats will then shift it about 100ft away from Giglio’s rocky shore.

That will enable engineers to slot into place some of the giant “sponsons” or hollow steel compartments that have been fixed to the port and starboard sides of the hull.

The compartments will act as giant armbands to raise the ship – water will be pumped out and compressed air pumped in, giving the vessel buoyancy.

At the end of phase one, the ship will be secured with the aid of a series of anchors and steel cables.

It will also be kept in position by two tugs on its offshore side, and a third located at the Concordia’s bow.

Phase 2

This stage will last about two days. It will involve attaching four chains and seven cables to the giant compartments on the starboard side of the ship – the side facing away from Giglio island.

Thirteen of the 15 compartments on the starboard side will be lowered to their final position. This was previously impossible because the cruise liner was wedged up against Giglio’s rocky seabed.

Phase 3

The operation to refloat the Concordia begins in earnest. Salvage teams will pump compressed air into the 30 compartments on the side of the ship, forcing out the ballast water. The compartments will be emptied step by step, raising the ship one deck at a time.

In total, four decks will emerge from beneath the water. The refloat will be finished when deck three resurfaces.

This phase is expected to take about three days. As the decks slowly emerge, they will be drained of water – the ship has been tilted at a slight angle to facilitate this.

By the end of this stage, the liner will have emerged about 45ft above the sea.

Phase 4

The ship is finally towed away from Giglio with the help of four tug boats. As its departure nears, the port of Giglio will be closed to all other traffic for about four hours, including ferries coming from the mainland. The Concordia will be towed north to Genoa, where it will be dismantled for scrap. The voyage is expected to take four to five days. The ship, with its convoy of 10 tugs and other support vessels, will travel at a speed of two knots. It will pass through open sea but salvage experts say it is robust enough to withstand rough seas of up to 8.5ft, “which statistics show to be highly improbably at this time of year”.

The route from Giglio to Genoa

Two alternative routes have been plotted for the convoy.

1 The first, which heads south of Giglio and then north past the tiny island of Montecristo and then parallel with Corsica, is 208 nautical miles long. It is well clear of French territorial waters.

2 The second possible route would take the ship north of Giglio and then head west between the islands of Montecristo and Pianosa, both part of the Tuscan archipelago. This route is 191 nautical miles long.

The decision about which route to take will largely depend on weather conditions in the Mediterranean.

The authorities say there is a negligible risk of pollution leaking from the ship as it is towed north, but just to make sure a number of measures have been put in place, including –

2 oil spill response vessels

2 vessels equipped with oil skimmers

16,000ft of absorbent floating booms

Portable infra-red sensors for the detection of oil on the surface of the sea at night

Two underwater CCTV cameras which will monitor the condition of the hull

Robot submarines known as Remote Operated Vehicles will also carry out checks

On board the Concordia there will be a quick response team of scuba divers who specialise in salvage operations

“During transportation to the final port of destination, the ship will be constantly monitored to detect and, if necessary, deal with any loss of material or spills from the hull,” said Costa Cruises, the Italian company that owns the liner.

Whales and dolphins

The Concordia will pass through the middle of a large marine sanctuary. The ship and its convoy will be preceded by a boat full of whale and dolphin watchers.

If any marine mammals are seen, the convoy will slow down until they pass.