ANCHORAGE - Divers began removing fuel from a sunken oil field supply ship in Alaska's Cook Inlet Sunday, but the work was soon halted when the inlet's notorious tides stated rocking a vessel being used as a staging area.
Divers pumped out about 1,000 gallons of an estimated 30,000 gallons of diesel on board the sunken Monarch, according to a spokesman for the owner of the 166-foot vessel.
But after the tides shifted, one of the anchors of the offshore supply ship Perseverance broke free from the sea floor, swaying the vessel from position.
"It's like anchoring in a river, but the river reverses its flow every six hours. The velocity of the tide is always changing and the direction, too, going in and out every six hours," said Jim Butler, a spokesman for Monarch's owner, Ocean Marine Services Inc. of Kirkland, Wash.
Crews pulled the two anchors and released a mooring line attached from the stern to the leg of an oil rig platform operated by Chevron Corp. The 207-foot Perseverance, which had been positioned over the sunken vessel, was taken to a sheltered bay while responders reviewed their mooring options.
Possibilities being discussed include dropping more anchors from other sections, repositioning the Perseverance or obtaining a different ship, Butler said.
The Monarch sank Jan. 15 when it was pinned by sea ice to the Granite Point platform during a delivery of supplies. ed during the mishap.
The vessel settled upside down on the sea bed near the platform, which is in the northern section of Cook Inlet about 45 miles southwest of Anchorage.
Responders, including state environmental regulators, warned last week about the challenges of working in conditions of the inlet. An oil spill response vessel and crew are standing by during the operation, which is expected to take more than a month.
"It is hard to exaggerate the difficulty of this fuel recovery operation," Gary Folley with the Alaska Department of Environmental Conservation said in a prepared statement. "Tidal currents in Cook Inlet are among the highest in the world, visibility for the divers is near zero, and the wreck is upside down."
Butler said Sunday's initial diesel recovery demonstrated the defueling system works. Once the mooring problem is resolved, divers will go down during slack tides. They'll use a wand attached to a pump on board the Perseverance to drain each of the Monarch's 12 fuel and oil tanks. Beside the diesel, almost 700 gallons of lube oil are on board the Monarch.
Three 30-minute dives are planned for each 24-hour period.
"The most critical thing is to ensure in all of our operation that we keep in mind safety," Butler said. "These divers are going down, working in an environment they can't see, to try to access fuel tanks on a ship that's upside down."