Speculation mounts that 250-year maritime mystery of Cook's HMS Endeavour may finally be drawing to conclusion off US coast

Not since the cities of York and Leicester fought a war of words over the remains of Richard III has a missing piece of history been so keenly contested.

The news, as yet unconfirmed, that marine archaeologists had finally identified Endeavour, the ship built in Cook’s home port of Whitby, which he took to Australia on his first voyage of discovery, could finally lay to rest one of the world’s great maritime mysteries.

An official announcement is expected today that a 25-year survey conducted by the Rhode Island Marine Archaeology Project has narrowed the search for the vessel from the sites of 13 wrecks to just one.

Images of the site in Newport Harbour where she is thought to rest, will also be released.

The news raised hopes that the remains of Endeavour – which, renamed Lord Sandwich 2, was used as a troop carrier during the American War of Independence but was sunk off Rhode Island in 1778 – might finally be excavated.

The project’s director, Kathy Abbass, was quoted in Australia as saying: “It is exciting – we are closing in. We can say we think we know which one it is.

“This is a vessel that is significant to people around the world, including Australia.”

But she said the ship’s identity could not finally be proven until after its excavation, which, she hinted, could begin next year, subject to “significant funding”.

The Rhode Island coast saw the sinking of a fleet of Royal Navy and hired British craft during the revolutionary war. Some 20 years ago, in a legal manoeuvre, known as “arresting the shipwrecks”, the state’s government claimed official ownership of all of them.

As a result, any attempt to return the remnants to Britain, or to Australia, for whom Endeavour is a part of the nation’s story, would most likely have to be decided by the courts.

The ship had been taken from Whitby to Plymouth in 1768. From there, under Cook’s command, it set sail with a year-and-a-half’s worth of provisions and a crew of 94 – all but 10 of whom suffered malaria or dysentery, with 30 cases proving fatal.

She sailed through Tahiti and the Pacific Islands before arriving in New Zealand in September of the following year.

Seven months later, she became the first ship to reach the east coast of mainland Australia, a site now known as Botany Bay. Two months after that, she survived a shipwreck when she struck what is now known as Endeavour Reef, within the Great Barrier Reef system.

Charles Forgan, a marine expert who is on the management committee of the Captain Cook Memorial Museum in Whitby, said the news of Endeavour’s sighting was “interesting” but suggested that New Zealand and Tahiti, as well as the US and possibly the UK, might lay claim to the wreck, should it be rescued.

The chances of it returning to Britain were small, he said.

“You’d need to find a squillionaire. You’ve got to get it out of the water, you’ve got to do what you did to the Mary Rose to preserve it, then you’ve got to get it across the Atlantic,” he said.

“If a ship is sunk, you preserve her on the spot where she met her end. What I would like, if they actually find her, is to be given an identifiable, small piece of Endeavour and lodge it at the museum.

“But that’s a long way off.”

The reported discovery of the wreck of HMS Endeavour comes 250 years and one month after it first set sail from Plymouth.

In July, the anniversary was marked in Whitby, where Cook’s apprenticeship was served, with a weekend festival. At the same time, a life-size replica of Endeavour sailed into the harbour to begin its new life as a tourist attraction there.

Andrew Fiddler, a hotel owner, had paid £155,000 at auction for the vessel – one of only two in the world.

The original Endeavour ended its life as a prison ship, having been sold off by the Navy for commercial use, but then leased back when ships were needed to transport troops across the Atlantic.