A large-scale air, land and sea search for the skipper of a yacht found beached with its engine still running but with no one on board was called off yesterday afternoon.
No sign of the man, named by police as 46-year-old Hany Nabil Mustapha, has so far been found.
A member of the public discovered his vessel, called Brigand, ashore with one of its sails up near Brighstone on the Isle of Wight.
Mr Mustapha, from Kingston-upon-Thames, south-west London, bought the small yacht in a private sale on Saturday morning and sailed from Poole Yacht Club in Dorset, where it was moored, at 10.05am the same day.
Dorset Police said that Mr Mustapha told staff at the yacht club that he intended to travel over to Hayling Island, near Portsmouth.
But following the discovery of his grounded yacht at 5.15pm yesterday, a five-hour search was launched involving two Coastguard helicopters and RNLI lifeboats, while broadcasts were made to passing vessels to be alert to objects in the water.
Despite the extensive operation, no sign of anyone was found and it was called off late last night, the Maritime and Coastguard Agency (MCA) said.
A fresh search began again at around 7am on Sunday for the skipper but it was called off again with nothing found about eight hours later.
A Solent Coastguard spokesman said: "The search has been suspended but if we get any new information that prompts us to an area then we will recommence a search."
Police tonight released images of the yacht and of Mr Mustapha who was last seen wearing a white sailing jacket, sunglasses and a hat.
Detective Inspector Pete Little, of Dorset Police, said: "We are obviously concerned about Mr Mustapha and I am releasing an image of him in the hope that the public may be able to assist us in locating him.
"Mr Mustapha's boat was found with nobody on board and with the motor still running off the coast of the Isle of Wight.
"We know he left Poole Yacht Club at 10.05am on Saturday October 27, and we believe he was planning on sailing to Hayling Island, near Portsmouth."
Coastguards have urged people about to set out to sea to ensure they are familiar with their boat and equipment, have proper training and ensure their crew wear well-maintained and correctly fitting lifejackets.
Mr Mustapha is described as being around 6ft 3in tall, of mid-European appearance with a stocky build. He has short, dark receding hair and a goatee beard.
Anyone with information about his whereabouts is asked to call Dorset Police on 101.