They think his name was Edward Teach. But they know almost nothing else about him.
So what stands out most is the legend. Edward Teach became Blackbeard, the 18th-century pirate who terrorized the Carolina coast.
"He's one of these larger-than-life figures, like Robin Hood," said Richard Lawrence, director of the underwater archaeology branch of the North Carolina Department of Cultural Resources. "That's what makes it so hard to separate the fact from the fiction."
Now, in the murky waters of the Atlantic, a mile from Beaufort, N.C., they are working on a wreck that they believe was his lead ship, the Queen Anne's Revenge. Lawrence and a team of marine archaeologists are diving to it, cataloging and bringing up artifacts. We went diving with them last year; they resumed the excavation this fall.
The work is slow. They can only work when weather and funds allow. Though the wreck lies in only about 20 feet of water, it is often so muddy that divers have trouble seeing their hands in front of them.
They're in something of a race against time. The sea is gradually reclaiming what remains of the ship.
"Any time the storms pass through, or the hurricanes," said Chris Southerly, the lead archaeologist on the project, "it causes erosive scour across the site, and exposes the artifacts that are there, and quite literally sandblasts them."
So far the team has found at least 24 cannon, a bell, pewter cups, medical devices, and a small amount of gold dust. Anything made of wood -- or any other organic material, for that matter -- was probably consumed by microorganisms in the water centuries ago.
Even so, historical detective work makes it likely this ship is Blackbeard's.
"Based on our documentary evidence, the Queen Anne's Revenge is pretty much the only candidate for this wreck site to be," said Southerly.
Blackbeard first caught the eye of British naval officers when he was still on their side. In the War of Spanish Succession (1701-1714) he hired on as a privateer -- essentially, a naval mercenary -- to plunder French and Spanish ships on Britain's behalf.
But when the war ended, he was left unemployed. He turned to piracy. Legend says he was a frightening figure, sometimes putting smoldering cannon fuses in his hair and beard to terrify the people whose ships he seized.
In 1717, he commandeered a French slave ship, La Concorde, renamed it the Queen Anne's Revenge, and used it and three smaller sloops to blockade Charleston, S.C.
On the run, having won a ransom worth 400 British pounds, Blackbeard is said to have run the ship aground off Beaufort Inlet in 1718.
After that, perhaps to make peace, the governor of the Carolina colony granted him a royal pardon. But Virginia's governor was not ready to go along. He sent troops to hunt him down on Ocracoke Island, near what is now Cape Hatteras, N.C.
On Nov. 21, 1718, they battled. Blackbeard was killed, his severed head mounted on a spike.
And that is where the story would end, if not for the discovery of the wreckage near Beaufort Inlet.
The archaeologists say that for lack of a good written record of Blackbeard's life, the best way to rediscover him is through the artifacts they bring up. The pieces are taken to a conservation lab at East Carolina University in Greenville, N.C., where the sea salts can be slowly dissolved from them, and they can be studied or put on museum display.
The process will take several more years. For now, there is the thrill of the chase.
"It's kind of the thrill of archaeology," said Southerly, standing with artifacts the divers had brought onboard their boat. "It's not just putting the pieces of the puzzle together. You're the first person to see this and touch this, if our identification is right, in almost 300 years."