Offshore oil platforms face an existential crisis similar to the rest of the world's: They're in trouble when the oil runs out. But whereas people can turn to other forms of power, rigs are doomed. If they're in the Gulf of Mexico, they'll often be sunk in place for marine life to colonize. (Quite successfully too. A recent study found that rigs are among the most productive fish hatcheries on the planet.) But by law, the dry rigs in the North Sea oilfield, Europe's largest, must be completely removed. Until now this has meant a long process of piecemeal dismantling, but this summer, when the Dutch company Allseas' newest ship, Pieter Schelte, goes into service, the job will get much simpler.

The Pieter Schelte's enormous size allows it to lift and remove entire North Sea oil rigs in a single operation. A process that currently takes months, or even years, will be accomplished in days.

To do a heavy lift on the water, you need to keep two things stable: the object being lifted and the device doing the lifting. Neither is overwhelmingly difficult in a sheltered harbor, or when the object isn't all that heavy. But the North Sea is no harbor, and an oil rig is heavy by any measure. The topside alone—the above-water portion where the living quarters and mechanicals reside—can weigh more than 48,000 tons, and the jacket, or the legs that support the structure below the surface and attach to the seabed, can be hundreds of feet long and weigh more than 25,000 tons.

An automated dynamic-positioning system keeps Pieter Schelte's frame stationary in the notorious North Sea currents. When it's time to lift a topside, the ship maneuvers so that the oil rig stands between its hulls, almost touching them. Eight immense arms slide out from the decks and clamp the topside (which was previously cut from the legs) in an unbreakable hydraulic grasp. To eliminate the tension created by the ship's yawing and pitching on the water, the clamps adjust constantly with the waves. Ballast water is pumped out of the hulls, lifting the ship and topside, and both bob free like the world's largest cork.

Removing a jacket is a different challenge, since the torque involved in rotating such a huge structure is enormous. A pair of lifting beams 540 feet long tilt down from the ship's stern, and the jacket—previously severed at the seabed—is winched tightly against them. When the beams tilt up again, the entire jacket ends up lying flat on the Pieter Schelte's deck: the Eiffel Tower on a sunbathing cruise. All in a matter of hours.

The Pieter Schelte took eight years to build, and that timing is no accident. Over the next 25 years, numerous tapped-out North Sea oilfields will need their abandoned rigs removed, with more rigs waiting to be installed in new sectors to replace them. The Pieter Schelte can do that too.

Illustrations by Axel Pfaender

(Illustrations by Axel Pfaender)

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io