Level instruments aid a spectacular recovery

The final cruise of the Costa Concordia unexpectedly ended in disaster. But the recovery of the wreck went according to plan, thanks to modern measurement technology.

The images were seen around the world. In January 2012, with more than 4200 passengers and crew on board, the Costa Concordia struck a reef on the western coast of Italy, ripping a gaping hole in the side and leaving the ship half sunk in the water. Thirty-two people lost their lives in the accident. Since then, the 290-metre-long wreck has rested on its side off the coast of the small vacation island of Giglio.

The salvage operation was just as spectacular as the accident. The objective was to raise the giant listing cruise liner in a single piece, thus preventing an environmental disaster and sparing the people of Giglio months of wrecking works taking place on shore.  “Uprighting the ship was an extremely delicate operation,” explains Antonio Festa from Endress+Hauser Italy. “To keep it from breaking apart, the ship had to be carefully and very evenly rotated.” To carry out the operation, specialists deployed state-of-the-art level measurement technology.

The salvage plan and preparations were one and a half years in the making. The unprecedented project - a wreck of this size had never before been raised in one piece - was awarded to an American-Italian consortium that brought in specialists from across Europe. “Our on-site partner was an Italian engineering firm,” explains Antonio Festa. “Endress+Hauser was then contracted by a Belgian company.”

A crucial role in the salvage and refloating effort was played by the sponsons, air-filled chambers that can be flooded with water and then emptied again. The sponsons attached to the Costa Concordia act like giant steel life vests to stabilise the wreck and provide buoyancy. The water level in the chambers is measured with pressure sensors. The 278 Waterpilot level probes used register the slightest hydrostatic changes, while two additional Cerabar pressure transmitters supply reference values.

“A constantly reliable level measurement was necessary to keep the hull from buckling while the ship was rotated,” adds Antonio Festa in explaining the mission. Apart from delivering precise measurements, the Waterpilot probes are extremely robust, withstanding even the harsh effects of salty sea water. “We also brought our entire range of expertise to the project,” says the pressure measurement specialist. “We provided support from the engineering phase and even made suggestions for the cable glands and centring sleeves for an easy installation of the measurement instruments.”

In the end the measurement technology passed its test with flying colours. In September 2013, specialists raised the crippled giant on its side during a mammoth 19-hour operation. Additional sponsons have since been attached to the starboard side of the ship, facing land, and over the period until July the ship has been refloated completely upright. The Costa Concordia has now been towed on its very final journey to an Italian port where the former pride of the Mediterranean will be scrapped.

www.theparbucklingproject.com