GIGLIO ISLAND – The Concordia wreck removal is an extremely complex technical engineering feat – considered the biggest salvage ever attempted on a ship of its size – with the deployment of the finest international expertise, state-of-the-art technology and unprecedented financial resources. The priorities of the project were clear from the outset: respect for the environment, workplace safety and protection of the Giglio’s island socio-economic fabric.
Cost considerations played no part whatsoever in the decision-making process. The world’s best cutting-edge technical solutions were chosen even though this led to a significant increase in outlay. According to current estimates, the total cost of the salvage will be well over 600 million euros. The size of this investment gives a good idea of the scale of the project, although not one cent of public money is being spent.
Activity at the site continues nonstop: about 500 salvage operators are working round the clock in shifts, 24/7.
PRELIMINARY OPERATIONS
Debunkering
The first step was defueling, which was vital in terms of protection of the marine ecosystem.
For this operation, also known as “debunkering”, Costa Crociere commissioned the world’s leading salvage experts Smit Salvage BV, who in turn worked with the Italian firm Tito Neri srl.
Preliminary work began at the end of January 2012 while the actual pumping out of the oil began on February 12, 2012 and ended on March 24, 2012. A total of 2042.5 cubic meters of fuel was removed from the ship.
This extremely complex and delicate operation was completed successfully without any discharge into the sea.
Collection and disposal of waste material and sewage
At the end of the debunkering, on March 25, 2012, the recovery of material deposited on the sea bed started and in total 24 tonnes were collected.
On January 14, 2012, the recovery of material floating on the surface was begun by the emergency response services and continued subsequently by Costa Crociere. On March 13, 2012 the operation to remove the sewage ended, Smit Salvage BV and Tito Neri having recovered a total of 240 cubic meters.
THE PROJECT
On April 21, 2012 Costa Crociere announced that, after reviewing the bids of the six finalists, it had awarded the tender for the contract to remove the ship in one piece to the international marine salvage consortium Titan-Micoperi Srl, a joint venture between Titan Salvage, a U.S. company owned by Crowley Maritime Group and a world leader in the recovery of wrecks, and Micoperi, an Italian company specializing in engineering and installation of offshore structures and undersea pipelines.
The winning recovery project was chosen based on stringent criteria, 90% of which referred to environmental protection, safety and the socio-economic fabric of the island community. That cost was not a key factor is underlined by the fact that the successful bid was actually the most expensive of the six submitted.
The wreck removal project includes contributions from some of the world’s top technical engineering experts, notably leading international naval and offshore engineering, architecture and design firms such as Ceccarelli Yacht Design, Studio Tecon of Milan, Spline of Venice, Overdick of Hamburg and the Dutch underwater solutions provider Disa International. All the work involved is being performed by industry leaders like the Italian companies Fincantieri, Cimolai, Rosetti, Trevi, Fagioli and Nuova Olmec and the British enterprises Furgo Seacore and FoundOcean. The companies charged with underwater drilling and engineering are global players in their segment and have worked for large oil and energy corporations.
Work on the removal of the wreck from Isola del Giglio began at the end of May 2012 following approval by the Service Conference convened by the Italian Government Emergency Commissioner Franco Gabrielli.
The salvage plan can be divided into five phases
1. Stabilization
In November 2012 the anchoring and stabilization of the wreck were completed, thus preventing the ship from slipping or falling off the steep spurs of rock on which it is perched at either end. This operation enabled the subsequent work to be carried out safely, even in adverse sea and weather conditions.
Stabilization was carried out by securing four anchor blocks to the sea bottom between the center of the wreck and the coast. Later, seven more anchor blocks and 11 towers were installed, for use during rotation of the ship into an upright position, the so-called “parbuckling”.
On top of each tower are two strand jacks with a hydraulic mechanism for pulling cables, which can be individually controlled via computer. Each strand jack will operate a cable connected to a steel chain (each loop of which weighs 205 kg) going underneath the wreck so that it can be attached to the offshore side of the ship. This system will be used to offset the forces bearing on the hull during rotation and guarantee that it can be raised to a vertical position.
2. False sea bed and sponsons on offshore side
The second phase was one of the most complex. The preparation of the false sea bed on which the ship will come to rest once it is rotated required a great deal of effort, much of which was done by a team of around 120 divers. The artificial support consists of steel platforms plus some 12,000 cubic meters of cement pumped into grout bags.
The grout bags were used to fill the gap because, as already mentioned, the ship is lying on two underwater reefs with a valley in between. The grout bags have eyelets for easy removal during clean-up operations.
The subsea platforms will provide a stable base for the upright vessel. There are six: three large ones (35 x 40 meters) and three smaller ones (15 x 5 meters).
The platforms are supported by pillars attached to the granite sea bed; these were put in place by drilling holes (about 2 meters in diameter and an average of 9 meters deep) using a closed-circuit system so as not to leave any debris in the sea.
The drilling operation was made particularly difficult on account of the uneven sand and granite sea bed.
During this phase, large tanks – known alternatively as “sponsons” – were welded to the side of the hull above water (the offshore side). These will be used during the parbuckling to provide leverage and later buoyancy. There are 11 of these large metal boxes, built by Fincantieri in four of its Italian shipyards. They are of considerable size: 10.5 m x 11.5 m with height of 21.8 or 33 meters, respectively the equivalent of a 7-storey or an 11- storey building. In addition, two “blister tanks” have been attached to the bow of the wreck; again built by Fincantieri, these massive tanks will provide around 4500 tonnes of buoyancy, stabilizing the whole bow and acting rather like a neck brace.
After parbuckling, another four sponsons will be installed on the left side, making a total of 15 in all.
3. Parbuckling
The actual parbuckling itself – the uprighting of the ship – is expected to take a whole day, with the operation likely to last between 10 and 12 hours; this is because the wreck will have to be rotated very slowly and vigilantly, with constant monitoring of the process. The strand jacks will be used to pull the steel cables attached at one end to the nine central caissons and at the other to the underwater platforms on which the wreck will come to rest once it is vertical. This is a very delicate phase, during which the forces involved have to be offset carefully to rotate the wreck without deforming the hull. Upon conclusion of this phase, the wreck will be resting on the false bottom at a depth of about 30 meters. (Further details are provided in the separate parbuckling fact sheet.)
4. Survey of the wreck and installation of sponsons on inshore side
Once the wreck has been turned upright, its overall condition can be surveyed; one of the highest priorities will be to check the right side, which is currently submerged and inaccessible. Following this assessment, any repairs required can be carried out and a reliable forecast can be made as to when the wreck will be refloated and taken away from the island. Another 15 caissons, already built and ready at Fincantieri, will be brought to Giglio and fixed to the right side of the wreck, in symmetrical positions to those on the left side.
5. Refloating
By means of a pneumatic system, the 30 sponsons attached to both sides will be gradually emptied of water, thus providing the buoyancy required for flotation. Upon completion of this operation, a portion of the hull of approximately 20 meters will be left submerged.