Donald Crowhurst
The 36-year-old sailor set out from England in a plywood trimaran as a competitor in the 1968 Golden Globe round-the-world yacht race. Though he had little prior experience and his boat, the Teignmouth Electron, was frighteningly under-built, Crowhurst managed to convince a wealthy backer, race judges and the media that he was a serious contender.
He wasn't. After several weeks fighting leaks and making slow progress, Crowhurst began sending bogus radio reports indicating amazing success. At one point, he claimed to have covered 391 kilometers in a single day -- a world record, at the time. In reality, however, Crowhurst had sailed off the route to the coast of South America, where he decided to lie low and wait for the other competitors to come back around. He spent 111 days in radio silence, then called in and reported another bogus position behind the race leader. But when a competitor sank trying to "beat" the Teignmouth Electron for second place, Crowhurst was overcome with guilt. He confessed all in his logbook, then stepped over the side and vanished into the Atlantic.