The massive anchor - weighing more than 1,000 kg (2,200lb) - is one of the largest artefacts on what is believed to be the Queen Anne's Revenge ship.
The anchor will now be put in a museum.
The flagship is thought to have sunk in 1718, five months after Blackbeard was killed by British sailors.
The US archaeologists said they had first planned to lift a bigger anchor but realised it was too well-attached to other items in the ballast pile.
They said that divers would continue to work next week and then decide how to proceed to retrieve other artefacts from the ship.