If, as divers who made the discovery hope, the wood turns out to come from a ship, it means they have found one of the oldest wrecks known - pre-dating the Pyramids and Stonehenge.
The wood has been discovered by members of the original diving team who located the Tudor warship Mary Rose which was lifted from the Solent off Southsea, also in Hampshire.
The team members have stuck together and, while investigating a Roman causeway in 1992, a short distance along the coast at Hayling, they found the pieces of wood, which they hoped might come from a Roman ship.
Initial analysis showed the wood was older than the 15th century and came from either a very cold or very hot climate, but only recently has carbon dating on the wood been carried out.
"The mind-boggling thing is it is not 2,000 years old as we were hoping, it turns out to be 6,431 years old," said a member of the team, Don Bullivant, 64, yesterday.
"We don't really know what we have got. It could be a clump of trees, which we think is unlikely, or it could be a building or it could be a ship. We are hoping very much for it to be a ship."
Electronic soundings of the site - it is about a mile off Hayling Island and its exact location is being kept secret - show what could be the shape of a vessel, although they could be misleading said Mr Bullivant.
"Hopefully it is a ship. If it is, we have the oldest ship in the world. The earliest recorded at the moment is 4,000 years old," he said. Six thousand years ago, he said, the Solent was a river, and the team has asked experts on the period for their help in identifying the wood.
Meanwhile they intend to return and carry out a further survey of the site, about 20 feet below the surface, and plan to get a second opinion on the age of the wood.
It is not clear as to whether the site would have been dry land or shallow water at the time, and the likelihood of a 100ft long vessel existing in northern Europe at that period is extremely remote.
The oldest boat yet found anywhere in the world - a large dugout canoe - was made 8,000 years ago in what is now the Netherlands, but it is known that humans were carrying out ocean voyages of 200 miles 25,000 years ago, and 50 mile sea journeys as long as 60,000 years ago.Reuse content