US and Australian archaeologists hunting for Captain Cook's HMS Endeavour may have finally discovered its location on the east coast of America.
The search in Newport Harbour, Rhode Island, has pinpointed one or two potential archaeological sites and excavation is expected to begin next year.
The Rhode Island Marine Archaeology Project (RIMAP) and the Australian National Maritime Museum teamed up to search for the Endeavour and will announce their results at an event on Rhode Island on Friday.
"It looks like the team have now got it down to one particular site of interest which is promising, which looks like its the right size and could be the Endeavour," Australian National Maritime Museum spokeswoman Shirani Aththas told AAP.
The discovery by archaeologists from the museum and the Rhode Island Marine Archaeology Project (RIMAP) is significant, but there is still a lot of work to be done.
Wood samples will be carefully collected from the wreck and taken back to a Sydney laboratory for testing.
"If the analysis shows that it's American timber then it's likely not Endeavour, if it shows that its UK timbers then that helps make it closer to being the Endeavour," Ms Aththas said.
The Endeavour is perhaps Australia's most significant ship after taking Cook on his voyage to Australia and the South Pacific from 1768-71.
The vessel later was renamed the Lord Sandwich and had a less impressive role as a British transport ship.
RIMAP founder Dr Kathy Abbass located historical documents in London that guided her team to the general area in Newport Harbour where they believe the Lord Sandwich was deliberately sunk by the British in 1778 during the American War of Independence.
Silt in the harbour may have helped preserve the vessel.
RIMAP began studying sunken British transports in Newport Harbor in 1993 with a remote sensing survey.
There were 13 potential vessels that could have been the Endeavour but the search has recently narrowed to possibly "one or two archaeological sites", RIMAP said in a press release.
The archaeologists will release a 3D photogrammetric image on Friday of a promising site located in an area just off the Goat Island shore near Gurneys Resort.
Despite the historical significance to Australia, it is likely the Endeavour, if found, will remain in Rhode Island.
In 1999 former Rhode Island Attorney-General Sheldon Whitehouse legally ensured Rhode Island's ownership of the historic Newport fleet, including the Lord Sandwich.
The Rhode Island Historical Preservation and Heritage Commission is also the custodian of the Newport Harbor shipwrecks.
The Rhode Island Coastal Resources Management Council has also established a "No Anchor - No Dive" zone around the archaeological sites to protect them.
This year marks the 250th anniversary of Cook's departure from England on the Endeavour.
The public is being asked to donate to RIMAP to help finance an artefact management facility needed to process, store, and display the artefacts that will emerge from the planned 2019 excavation.
© AAP 2018