http://www.nytimes.com/2015/01/04/magazine/the-wreck-of-the-kulluk.html?_r=0

NY Times MAGAZINE

The Wreck of the Kulluk
By McKENZIE FUNK
DEC. 30, 2014

In 2005, Royal Dutch Shell, then the fourth-largest company on Earth, bought a drill rig that was both tall, rising almost 250 feet above the waterline, and unusually round. The hull of the Kulluk, as the rig was called, was made of 1.5-inch-thick steel and rounded to better prevent its being crushed. A 12-point anchor system could keep it locked in place above an oil well for a full day in 18-foot seas or in moving sea ice that was four feet thick. Its drill bit, dropped from a 160-foot derrick, could plunge 600 feet into the sea, then bore another 20,000 feet into the seabed, where it could verify the existence of oil deposits that were otherwise a geologist’s best guess. It had a sauna. It could go (in theory) where few other rigs could go, helping Shell find oil that (in theory) few other oil companies could find.....

[The story is too long to copy. Go to the link with pictures, maps, etc.]