Crews finished transferring about 49,000 gallons of fuel and water mixed from the two damaged tanks late Friday, said Jim Butler, a spokesman for Crowley Maritime Services. On Saturday morning, the U.S. Coast Guard, state of Alaska and Crowley -- owners of the stricken tug -- had agreed on a tow plan to bring the boat back into the Port of Valdez, Butler said.
Officials had hoped to remove the fuel from the tugboat's tanks early Friday before towing it back to Valdez, but diesel removal was halted after about 10 minutes when workers noticed a new sheen on the surface of the water, said Coast Guard Lt. Erin Christensen, a spokeswoman for the joint information center.
Helicopter flights measured the sheen at 50 feet wide by one-mile long, Christensen said.
The 136-foot tug Pathfinder had just finished checking for dangerous ice and was heading back to port in Valdez when it hit Bligh Reef at 6:15 p.m. Wednesday.
The boat is part of the Ship Escort Response Vessel System that was created after the Exxon Valdez ran aground in 1989 and spilled nearly 11 million gallons of crude oil -- the worst ever U.S. spill.
Six fishing vessels plus Coast Guard cutters and salvage vehicles worked to skim the diesel off the surface of the water.
U.S. Sen. Mark Begich of Alaska said it was troubling that a spill response vessel "managed to run aground on one of the most well-marked and well-known reefs in the Northern Hemisphere."
It wasn't yet known how much spilled. The Coast Guard said Thursday that two of its tanks -- containing an estimated 33,500 gallons of diesel fuel -- were damaged. But an estimate on how much fuel spilled couldn't be done until the fuel was off-loaded.
The SERVS system provides two escort tugboats for each tanker traveling through the sound after leaving the Valdez Marine Terminal with North Slope crude delivered through the trans-Alaska pipeline.
The grounding of the tug was very different from the Exxon Valdez accident in which an enormous amount of black crude oil spilled. The tug was carrying much lighter diesel fuel that will evaporate in time, Coast Guard Petty Officer Jon-Paul Rios said.