the MV Tricolor, a huge Norwegian freighter carrying 2,800 BMWs, Volvos and Saabs went down in the English Channel in 2002... they cut it in neat slices, right through some cars, to lift it out of the channel

Because the Tricolor sunk in a high-traffic shipping lane at only 30 meters of water, it was subsequently hit by not one, not two, but three more freaking ships.

To cut so cleanly, underwater, the salvage company placed two platforms abeam the sunken ship, and passed a big-ass cable coated in Widia, a type of sintered tungsten carbide under the ship, then sawed back and forth

http://www.core77.com/posts/45756/Real-Life-Cutaways-Heres-How-You-Saw-a-50000-Ton-Ship-Carrying-2800-Cars-Into-Slices-With-the-Cars-Still-Inside