Mystic - Over the past seven years and eight expeditions, the Ocean Technology Foundation has explored thousands of potential targets in the North Sea in an effort to find the wreck Bonhomme Richard, the flagship of Revolutionary War naval hero John Paul Jones.

But last month, during an expedition with a private organization that donated the use of a search vessel, the group explored its most promising site yet, a debris field that includes an anchor, buried wooden planks and encrusted iron.

Melissa Ryan, the group's project manager, said Thursday that of all the targets explored since 2006, none have had characteristics that even come close to this site, which appears to be a mostly buried wooden shipwreck with iron objects.

This summer, the Ocean Technology Foundation will return with two French naval vessels to further explore the site in an effort to identify whether the debris is indeed the wreck of the Bonhomme Richard.

"If we're lucky and can prove this is the Bonhomme Richard, it would be the maritime discovery of the century," she said.

The story of the Bonhomme Richard and Jones, or at least his famous quote, "I have not yet begun to fight," is familiar to anyone who has taken a U.S. history course.

The Bonhomme Richard sank in September 1779 after a battle with the HMS Serapis. It was during the battle that Jones is said to have shouted one of the most famous lines in U.S. history to the captain of the British vessel.

The crew of the Bonhomme Richard eventually captured the Serapis after a bloody, three-hour battle, but the Bonhomme Richard sank off Flamborough Head, on the Yorkshire coast of England, where those on land witnessed the battle. One of the men aboard the ship was Nathaniel Fanning of Stonington.

From April 15 to 20, Ryan said the group went back and explored a promising target that it had located in the last two hours of a 2012 search with the French Navy.

Using a magnetometer, side scan sonar and a remotely operated vehicle, the search found an anchor, wood planks that have been buried in the sand and metal objects. In addition, there were signs that iron ballast, which was aboard the ship, could be buried. Ryan said she hopes what appears to be circular objects are cannonballs. There was no evidence of a modern ship, such as a boiler or pipes.

The metal objects are now "concretions, which are a combination of rust, shell, marine organisms, calcium carbonate, and other materials that form a layer around iron objects as the iron oxidizes and reverts back to its natural state," according to Ryan's blog.

The wreck, which is in 70 meters of murky water, is located at the edge of a search area where sophisticated computer models have indicated the wreck may be based on eyewitness accounts of the battle, ships' logs, information on tides, winds and weather, battle damage and how the ship would have drifted before it sank.

Ryan said historians and other experts are analyzing the images as her organization prepares to return to the site this summer.

They will again use a magnetometer to detect buried metal such as cannons and high-resolution sonar. They are also looking for an organization to provide them with the use of a small autonomous underwater vehicle to use in the search. She said that would allow searchers to create a photo mosaic map of the wreck site.

"It's important we do an archeological study before we disturb anything," she said, adding the mosaic would also offer better resolution images.

Ryan said her group also wants to extend the search area because other parts of the wreck may lie nearby.

"I keep thinking that every one of these expeditions will be our last," she said.

But Ryan said the search is no longer frustrating.

She said that more than 500 people have worked on the effort over the years in various capacities, and their personal investment in the missions has been impressive.

"People understand the historical significant of this ship. They really want to find it," she said.

"Whether it's their first mission of their third, they are always excited," she said.

Those interested in the search can read Ryan's updates and view photos of the wreck site at searchforbhr.blogspot.com.

Information about the search is also at www.oceantechnology.org. The organization continues to seek funding for its work, which is a costly venture because of the need to secure ships and equipment.

j.wojtas@theday.com