Attached to a drilling prospect, the Kulluk is designed to handle waves 18 feet high. When disconnected from a well, it's designed to handle seas to 40 feet. Garth Pulkkinen of Noble Corp., the operator of the drill ship, said it was never in danger of capsizing.
The vessel first separated from a towing vessel Thursday night south of Kodiak Island.
The vessel Thursday was carrying a skeleton crew of 17 as it was towed by the Aiviq from Dutch Harbor in the Aleutian Islands to Seattle for maintenance. The tow line broke at a shackle attached to one of the vessels.
"It was new. It was inspected before it left Dutch, but it broke," said Shell Alaska spokesman Curtis Smith.
The Aiviq crew alerted the Coast Guard and the cutter Alex Haley from Kodiak motored to the vessels. Two vessels under contract to Shell also left from Seward.
Before a line could be reattached, the Aiviq's engines failed, possibly from contaminated fuel. The Alex Haley attempted to secure the drifting drill ship but that line failed and wrapped itself around one of the cutter's propellers, requiring the cutter to return to Kodiak on one propeller.
With additional heavy weather predicted, the Kulluk crew was evacuated Saturday from the heaving drill ship. Crew members hooked up emergency tow lines and left them trailing behind the vessel in case they were needed.
The Aiviq, with its engines restored, and a tug re-established lines to the drill ship, only to have the lines break Sunday afternoon.
At about 12:45 a.m. Monday, during a lull in the storm, the crew of the Valdez-based tugboat Alert grabbed the original 400-foot line trailing the free-floating drill ship. Later in the morning, the Aiviq grappled aboard one of the emergency lines.
The vessels moved north Monday afternoon were heading toward shelter in Port Hobron on Kodiak Island's southeast side.