GALVESTON, Texas (AP) _ A buckled fuel barge that spewed 5,000 barrels of oil into Galveston Bay was towed toward a shipyard where investigators planned to study its hull for clues to why it ran aground.

The 275-foot Buffalo 292 will be placed in dry dock, and Coast Guard investigators hoped to take a first look at its hull today to learn why the barge buckled, said Lt. Greg DeLong, a spokesman for the Guard.

On Wednesday, the remaining oil was removed from the barge's 10 undamaged tanks before it was towed up the Houston Ship Channel.

The barge was no longer oozing oil after crews cleaned up globs of goo that fouled more than a mile of beaches at the peak of spring break tourist season.

Crews have cleaned up 42,000 gallons _ about 20 percent _ of the black oil that spilled in the channel, DeLong said. Another 42,000 gallons of lighter grade oil components had evaporated by Wednesday.

Two large skimming vessels, directed by a Coast Guard helicopter using infrared cameras, worked to clean up two larger concentrations 30 and 40 miles offshore as darkness fell.

Workers also collected oil splotches from 2,000 yards of beach on Galveston's eastern tip.

Thirteen oiled birds, mostly ducks, were recovered, said Jeff Long, spokesman for the Texas General Land Office. One later died.

The Coast Guard said 50-mph wind gusts and choppy seas might have contributed to the breakup of the barge, owned by Buffalo Marine Service Inc.