For years, enthusiasts have been trying to identify the whereabouts of the USS Bonhomme Richard, which sank in 1779 following a swashbuckling seabattle with the British Navy some 25 miles off the Yorkshire coast. And when 12 months ago an expedition led by the Connecticut-based Ocean Technology Foundation felt they had come tantalisingly close to solving the mystery, appetites were whetted even further.

So recently another delegation from America arrived in England armed with £250,000, the latest technology and the hope of pinpointing the ship, which is held in the US with as much regard as the HMS Victory in Britain, among five likely candidates on the sea bed just off the cost of Flamborough.

"In spite of some adverse weather conditions and the relatively short three days we had at sea, the cruise was very productive, in that we were able to discount two of our five previously identified targets as being the Bonhomme Richard," said the ever-optimistic OTF project leader Melissa Ryan.

"We also visited a third target, which was completely buried by a sand wave and was not conducive to exploration by the remotely operated vehicle.

"It is not unusual for objects on the seabed to become covered and uncovered due to the very dynamic North Sea environment, but this certainly adds extra challenges to working in that region.

"Data gathered from this cruise has allowed us to further narrow our search area as we continue moving forward with the project.

"We are applying for funding in the States and will continue our efforts with the aim of mounting another expedition next summer to investigate the remaining targets and conduct additional remote sensing operations, if necessary."

British enthusiasts themselves have, for years, been trying to identify the whereabouts of the Bonhomme Richard, captained by the Scottish fugitive John Paul Jones, and a benign trans-Atlantic war of words has raged for some time over the exact location and identity of the mystery ship – the precise whereabouts of which is still frustratingly unknown.

Jones himself is best known in naval circles on both sides of the Atlantic as an emblem of anti-British defiance, and as a hero of the American revolution, almost in the swashbuckling Errol Flynn fashion.

In the Battle of Flamborough Head on September 23, 1779, the Bonhomme Richard, under his command, watched from the Yorkshire cliff-tops by enthralled onlookers, destroyed the far superior British frigate HMS Serapis, but not before Jones' weaker American ship had been holed beneath the water line.

With his ship burning and sinking, and with its flag or ensign believed to be shot away, Jones was asked by the British commander if the American ship had surrendered or "struck her colours".

And in a reply which has become the equivalent of Churchillian by American naval standards, Jones defiantly replied "I have not yet begun to fight", a phrase which is now legendary in every school in US history.

The team was hampered by poor weather conditions in its three day expedition in August, but like their rebel counterparts, the Americans say they haven't given up the fight.

"It's always disappointing when it doesn't happen the first time, but this was a good, productive cruise. We're happy with the progress we made. This is not just about looking for a shipwreck. Jones gave the American people a hero when they needed one, and showed the world that the young continental navy was a force to be reckoned with.

"Regardless of his nationality, it is Jones's spirit courage and tenacity that has really left an imprint on our naval forces for the past few centuries. I don't think the word surrender was part of his vocabulary and he serves as an example and inspiration for our Navy today."

Jones's body was ceremonially removed from his interment in a Parisian graveyard and brought to the United States aboard the USS Brooklyn, escorted by three other cruisers.

On approaching the US coast, no fewer than seven American battleships joined the procession escorting Jones's body back to the US. His remains were finally re-interred at Annapolis, Maryland, in the United States Naval Academy Chapel. The ceremony was presided over by President Theodore Roosevelt.

The Scots-born "Father of the American Navy's" last act of defiance might be to keep his flagship hidden for all time.