The search for missing scientist Jim Gray, founder of Microsoft's Bay Area Research Centre in San Francisco, and winner of the Turing Award, has moved online, with computer users everywhere urged to help in the hunt.
Gray was reported missing over a week ago after taking his 40ft yacht on a cruise to scatter his mother's ashes.
The US Coast Guard stopped searching for him on Thursday, stating that it had covered 40,000 square miles and found not so much as a life raft.
Google founder Sergy Brin has bankrolled the purchase of satellite imaging of the area, and Amazon has set up a website where concerned people can examine the images and flag them up for anything likely to be of use to rescuers.
Private planes have also been chartered to search in creeks and inlets along the coast.
"This is the largest civilian, privately sponsored search effort I have ever seen," Captain David Swatland, deputy commander of the Coast Guard sector in San Francisco, told the New York Times.
Nasa has sent up one of its own aircraft to help in the search, a modified U spy plane similar to that used in the Cuban Missile Crisis.
The plane uses video and stills cameras to cover around 7,000 square miles of sea before putting the film on a modified F/A-18 Navy fighter for fast delivery to the search centre.
"The camera can pick up something from 50,000 feet as small as that boat," said Alan Brown, spokesman for NASA's Dryden Flight Research Center at Edwards Air Force Base. "That doesn't mean it's going to, but it's worth a try."
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