The Costa Concordia cruiseliner sank more than a year and a half ago, and to this day it sits off the coast of the Italian island of Giglio, becoming more and more decrepit. The first step of getting it off the rocks its stuck on came earlier this week, when engineers finally righted the ship. Here's how they did it.
Moving the beached ship definitely wasn't easy, with a number of complications right from the start. Not only is it massive and onerous and ships are meant to float, not to be lifted, but it has a massive gash full of rocks and boulders in its side, its full of standing water, and, perhaps most tragically, the bodies of two of 32 people killed are thought to be still inside.
Oh, and it was lying on a slope, so if they tried to just roll it over all they'd end up doing was flipping it onto its other side, or, even worse. They'd see the entire thing slip below the waves.
Luckily, none of that happened, and this week we've got an upright ship, a relieved crew, and some awesome gifs of the whole thing.
Building A Platform
Before the ship could be lifted by company Titan Salvage, it needed to be rolled over into an upright position, in a procedure known as parbuckling. Unfortunately the ship didn't come down over a level seabed, otherwise the whole operation would've been a lot easier. First a steel-and-concrete platform needed to be constructed and anchored underwater, into the seabed itself, for the Costa Concordia to sit on before it could be floated once more. It was built in six sections, and supported by pillars over five feet in diameter that were anchored more than 30 feet into the granite face of the island.
Once the platform was in place, the parbuckling could begin.
Image via Wikicommons
Righting The Ship
Before the ship could be floated and towed away, it needed to be rolled into an upright position. Parbuckling ships that are close to the shore has historically relied on attaching winches on land to the ship and then essentially pulling it upright, like this:
That's the USS Oklahoma, which capsized after the Japanese attack on Pearl Harbor. The Concordia, however, rolled the wrong way for winches to be easily attached to the shore. That meant that the operation would rely on a system of pulleys and sponsons either floating on barges, or attached directly to the ship.
First massive jacks were used to get the process going, and once the ship was freed off the rocks it was dug into, the cables, attached to cranes and pulleys on barges, took over. The most fascinating part happened when enormous gray boxes, known as sponsons, that were attached to the dry side of the ship began to touch the water.
The sponsons themselves were filled with water to act as a counterweight to the ship itself, kind of like when you pull someone out of the water when you're on a boat. The general advice is not to pull upwards, but to pull backwards, and your weight will eventually lift the person without too much exertion. That was the idea here, to let gravity do most of the work. With the sponsons filled with water, the cables went slack and the ship finally went level.
Crowley Maritime, the parent company of Titan Salvage, made this video to show what the whole thing looked like in action:
Images via Getty
Floating the Beast
Even though the ship was upright, the salvage operation isn't finished yet. The ship now has to be floated, if not entirely to where it was before the incident, at least to a point where it could be towed away. Unsurprisingly, ships aren't very hydrodynamic when they're half-sunk in the water and trying to drag that around would be a bit, shall we say, difficult.
Using more giant tanks attached to the side of the ship, compressed air will be pumped into the sponsons. As air is lighter than water, the ship should then float to a point at which the whole thing can be towed to a port to be scrapped. And you'd want to scrap it, considering the side of the ship that came out of the water looks like this:
The cost of the salvage so far? Only about $800 million.
Images via Getty