Gold coins
Gold coins recovered from the Whydah by Barry Clifford (wiki commons)

An underwater explorer believes he is close to discovering a pirate's treasure trove off the coast of Massachusetts after finding a path of gold.

Barry Clifford says he has found a "yellow brick road" that is "sprinkled with gold dust" running along the sea floor of the wreck site of the Whydah, near Cape Cod.

The team is looking for the pirate ship, which sank during a brutal storm in 1717. On board, it had plunder from 50 ships and since the discovery of the site in 1984, over 200,000 artefacts have been found but the ship itself has remained hidden.

The Whydah was captained by Black Sam Bellamy, an English pirate who took the ship from Dutch buccaneer Captain Lawrence Prince.

Bellamy was the wealthiest pirate in recorded history after capturing at least 53 ships before his death at the age of 28 during the Whydah sinking.

Earlier this year, Clifford found that even more treasure is likely lying with the Whydah after finding documents indicating that the pirates on board raided two ships in the weeks before it sank - the booty included over 400,000 coins.

The Whydah sank during a storm 300 years ago near Cape Cod (wiki commons)

"We think we're very, very close," Clifford said. He and the team recently completed a dive to the path made of gold and artefacts that extends between two sites of the wreck - a cannon pile and a large piece of wood believed to be the ship's stern.

The team believes the treasure poured from the stern as the ship broke up and sank.

However, searching the water has proved challenging. One of the divers said that visibility was near zero and it was like swimming in a vat of black jelly.

"You're going by your feel, your touch, your hands, and the ping of a metal detector," Diver Jon Matel said. "When that thing goes off, it's a great feeling."

Clifford said their evidence suggests they are extremely close to finding the Whydah, which would be the only authenticated pirate ship wreck in US waters, but that they will have to wait until next year to continue the search because of the weather conditions.

He said this will prove a particularly frustrating time for him: "I'll wake up in the middle of the night this winter and go, 'Oh my God, I know what that means,' when I'm reviewing something from the Whydah," he said. "And then I can hardly wait to get back there in the spring."