Now, marine archaeologists believe they may have identified the long-sought wreck, beneath the waves of a busy US harbor in Rhode Island. The finding comes in time for the 250th anniversary of Cook's voyage from the U.K.to Australia aboard the vessel, the first recorded European contact with that continent. But the location of the historic ship had been a mystery for centuries, with one theory putting it at the bottom of the Thames River in London. It was hired as a British troop transport during the American War of Independence and was scuttled in a blockade off Rhode Island in 1778. The group's marine archaeologists and volunteers have spent the past 25 years narrowing the list of suspects to determine which of the wreck site might be Endeavour.
The Rhode Island Marine Archaeology Project began to try to map and identify those remains starting in the early 1990s, and eventually figured out that the Lord Sandwich was the same ship as the HMS Endeavour.
"The American army was assembled on the mainland and the French sent a fleet to help", RIMAP executive director Kathy Abbass told CNN in 2014.
"This is a vessel that is significant to people around the world".
A replica of Captain Cook's ship "Endeavour" is seen at the Australian National Maritime Museum in Sydney on September 19, 2018.
The British Royal Navy later sold the vessel, which was renamed Lord Sandwich.
A full-sized replica of Captain Cook's famous ship Endeavour, in Whitby Harbor, England on June 1, 2018.
"They've got five boats there and Endeavour is probably the largest and so really at the moment it's buried in the mud", Mr Moran said. "They took everything off of the ships and sunk them right before the Battle of Newport".
Definitive proof will come from forensic tests on the timbers.
For weeks, Cook and the Endeavour made their way slowly toward the Pacific, pushing south and west until they had cleared Cape Horn, at the southernmost tip of South America.
Charles Forgan, of the Captain Cook Memorial Museum in Whitby, said he believed any wreckage is technically a "spoil of war" and so belonged to the United States.
HMS Endeavour, Captain James Cook's old boat that he famously used to discover a few places that already existed, has apparently been found after spending almost 250 years lost at the bottom of the sea. "It'll be bits of wood and vessel that might be recovered". The state of Rhode Island is presently the Endeavour site's owner (whichever wreck site it might be), but if found and raised, artifacts from the vessel could be the subject of an global custody battle between claimants.