While the Discoverer was making its way south from the Chukchi, the Kulluk was still sitting in the Beaufort Sea. It couldn’t leave until it discharged most of its 83-person drilling crew. To shuttle workers to and from the Beaufort shore, Shell had hired PHI, a helicopter company that it had long used in the Gulf of Mexico. As the weather worsened, the helicopters were often unable to make the trip. They had no de-icing equipment, and their pilots were unfamiliar with the Arctic. Adding to the delays, rough seas made it difficult to refuel the Kulluk’s tugboat, the Aiviq. The rig remained at 70 degrees north well into November. Snowdrifts piled up on its deck, and ice the consistency of a Slurpee formed in the water around it.

As Shell prepared the rig for the return voyage to Dutch Harbor and potentially on to Seattle, it again tried to hire MatthewsDaniel, the marine warranty-survey company that it had asked to independently examine and approve its June 2012 tow north. This time the company was unavailable, Shell told investigators. But according to a 152-page report on the grounding of the Kulluk that the Coast Guard released in April 2014, MatthewsDaniel was concerned that the second leg of the voyage might prove too dangerous. In an email, MatthewsDaniel told Shell that it “would not approve a tow of the Kulluk from Dutch Harbor to Seattle during the month of November as weather data shows that seas can reach as much as 10 meters in the Gulf of Alaska.”

Shell hired a different warranty surveyor, GL Noble Denton (not affiliated with Noble Drilling), that agreed to approve both legs of the trip. When the Kulluk arrived back at Dutch Harbor, it was almost Thanksgiving.

By December, the Gulf of Alaska is one of the stormiest places anywhere. According to the National Weather Service, gale-force winds are present 15 percent of the time during December and January; 20 percent of the time, the sea swells top 17 feet; and in an average year, hurricane-force winds hit two or three times. The sensible approach would have been to wait out the winter in Dutch Harbor, safe in the Aleutians, on the edge of the gulf. The Kulluk had a customized berth in Dutch Harbor — rounded to match its hull — and would be better positioned to go back up to the Arctic the following summer and complete the new wells. But the company wanted to make off-season upgrades to the Kulluk that would be either impossible or too expensive in Dutch Harbor. And there was another consideration: If the Kulluk was in an Alaskan port on New Year’s Day, executives believed, it would be subject to a state oil-facilities tax of as much as $6 million. In late December, a spokesman confirmed Shell’s fears in an email to a longtime reporter at a local newspaper, The Dutch Harbor Fisherman, writing, “It’s fair to say the current tax structure related to vessels of this type influenced the timing of our departure.” (“That was an unfortunate article,” Pete Slaiby, the Alaska vice president for Shell, told a crowd in Kodiak in early January, reiterating the need for “very specific things” it needed done on the mainland.)

The Aiviq also had problems. Towing the Kulluk over the summer, the tug had run into a storm that sent saltwater flooding over its back deck and into the fuel vents and interior spaces, damaging cranes, electronics and heating systems. In a separate incident on the November return from the Beaufort Sea, the tug had an electrical blackout, and one of its main diesel engines overheated, rendering it unusable until it was repaired in Dutch Harbor. By law, according to the Coast Guard report, such system failures should have been reported to the Coast Guard. They were not. The Aiviq’s captain sent an email to Chouest headquarters titled “Storm Damage Lessons Learned” and recommended that they raise the height of its fuel vents to avoid future submersion during the next big tow through heavy Alaskan seas, but this was never done.

On the morning of Dec. 21, as the Aiviq and Kulluk crews prepared to depart on the three-week journey back to Seattle, Shell’s new warranty surveyor took careful note of the certificates for the steel shackles that would connect the two vessels and bear the dead weight of the giant Kulluk — without noticing that they had been replaced with theoretically sturdier shackles of unknown origin. He examined the shackles but had little means by which to test their strength. He did not ask the crew to rotate the shackles, as one might rotate tires on a car. He did not consider it part of his job, he would tell Coast Guard investigators, to examine whether Shell’s overall plan to cross the Gulf of Alaska made any sense.