An anchor from a shipwreck thought to be Blackbeard's flagship, the Queen Anne's Revenge, was so unstable that divers in North Carolina retrieved it Wednesday rather than waiting until next year.

Divers raised the 4.5-foot, 160-pound grapnel, or anchor, from the wreck in the Atlantic Ocean near Beaufort on Wednesday and will display it Thursday at the North Carolina Maritime Museum in Beaufort. The anchor originally had four prongs, but now has 1 1/2.

Two divers put straps on the anchor, then small lift bags that they filled with air, said Mark Wilde-Ramsing, the director of the Queen Anne's Revenge shipwreck project. When the grapnel reached the surface, a crane brought it on the boat.

"It went great," he said. "It went as smooth as it could be."

The grapnel probably was an anchor for a smaller boat that would have been used to transport items between ships or from land to ship, Wilde-Ramsing said.

Archaeologists and conservators with the state Department of Cultural Resources say the grapnel was at risk of washing away after nearly 300 years in the sea and might not weather possible storms until next year, when a full-scale expedition is planned.

The rest of the shipwreck looks very stable, Wilde-Ramsing said.

Queen Anne's Revenge was a French slave ship that measured about 100 feet long with three masts and a crew of 150 to 200. Blackbeard captured the ship, then known as La Concorde, in 1717 and renamed it before it ran aground off Atlantic Beach a year later. The shipwreck, discovered in late 1996, is within sight of Fort Macon State Park.