A sketch of the HMS Endeavour, which was believed to have been scuttled during the American Revolution.

The Rhode Island Marine Archaeology Project said in a release it believes it has found the ship Cook used to explore Australia before it was scuttled off the coast of Rhode Island in 1778.

James Cook’s Endeavour — a ship that vanished off the map so completely that there are accounts of its possible final location across the globe — may be in the waters off Newport, Rhode Island.

The Rhode Island Marine Archaeology Project (RIMAP) will announce on Wednesday that it is between 80 percent and 100 percent certain it knows the location of the legendary explorer’s lost ship, according to information on its website.

The organization said Endeavour was renamed the Lord Sandwich after Cook’s first voyage, used as a transport ship for British soldiers in the American Revolution, and then scuttled in Newport Harbor during the August 1778 Battle of Rhode Island.

RIMAP used documents from London to discover that the HMS Endeavour/Lord Sandwich was one of 13 ships that sank in the harbor during the battle. The organization believes the ship is in a specific area where five ships were scuttled, and it has already mapped four of the wreck sites there.

Historic documents showed that one group of five ships included the Lord Sandwich. Four of the sites have been mapped, with a fifth site possibly found with remote sensing data.

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“That means the Rhode Island Marine Archaeology Project now has an 80 to 100% chance that the Lord Sandwich is still in Newport Harbor, and because the Lord Sandwich was Capt. Cook’s Endeavour, that means RIMAP has found her, too,”RIMAP said in a statement.

The organization will be working to determine each vessel’s structure and related artifacts.

“All of the 13 ships lost in Newport during the Revolution are important to American history, but it will be a national celebration in Australia when RIMAP identifies the Lord Sandwich ex Endeavour,” the organization said.

Cook, a British explorer, sailed on the HMS Endeavour around Cape Horn in Africa, and visited Tahiti, New Zealand and Australia. While Cook wasn’t the first European to visit Australia, his crew extensively studied the country’s eastern coastline. A town there is named for the year of the crew’s arrival — Seventeen Seventy.

Cook explored Tonga, Easter Island, Norfolk Island, New Caledonia and Vanuatu on his second voyage.

He was killed in 1779 during a trip to the Sandwich Islands, now known as Hawaii.

The Endeavour was sold and used to transport British troops before it met its watery grave — lost for more than two centuries.

Wednesday’s announcement comes 240 years after Rhode Island’s colonial legislature disavowed its loyalty to the King of England.

“For RIMAP to be closing in one of the most important shipwrecks in world history, for that ship to be found in Newport, and for it to have an international reputation, should be an intriguing birthday gift for all of Rhode Island,” the organization wrote.