When he discovered that the ship's underwater plow was stuck at the bottom of the Arctic Ocean, 50 miles off Alaska's coast, Frank Cuccio thought of Ernest Shackleton. In October 1915, the British explorer was forced to make a desperate escape from the Antarctic after pack ice and floes crushed his ship, the Endurance. The vessel Cuccio was aboard, the Ile de Batz, had been laying fiber-optic cable along the inhospitable route known as the Northwest Passage. But the Ile de Batz's 55-ton excavator, which had been cutting a trench for the cable, had dug too deep in the hard-clay seabed. If they didn't unclench it fast, the ocean surrounding them would soon freeze. “I realized we don't have time to fool around, or we're going to get trapped in a Shackleton situation,” Cuccio recalls. “The weather was getting uglier, and other ships had been gone for weeks."