An air and sea search was launched after a yacht was found beached with its engine running but with no-one on board, Coastguards said.
A member of the public discovered the yacht, called Brigand, ashore with one of its sails up near Brighstone on the Isle of Wight on Saturday evening.
A five-hour search for its skipper, who has not been named, was launched involving two Coastguard helicopters and RNLI lifeboats. Broadcasts were also made to passing vessels to be alert to objects in the water.
The Maritime and Coastguard Agency said despite the extensive operation no sign of anyone was found. Solent Coastguard watch manager David Williams said it is believed the skipper left Poole in Dorset on Saturday morning.