LOS ANGELES (AP) -- One of Michael Wilson's sons is a former contestant on "Survivor." But Wilson is a real survivor.

Wilson told Coast Guard rescuers he'd been thrashing around in the stormy ocean off Ventura County for five hours after a wave knocked him off his boat. He was treated for hypothermia and exhaustion Wednesday.

The mortgage business owner intended to take his 35-foot Viking power boat from Channel Islands Harbor, northwest of Los Angeles, to the west end of Anacapa Island about a dozen miles offshore in preparation for selling the vessel, according to his mother and his report to the Coast Guard.

He put the boat on autopilot to do some work when he was knocked into the water by a wave at about 9 a.m. Tuesday, according to the accounts, and the boat motored away, leaving him in 6-foot swells.

Wearing only a long-sleeve T-shirt, shorts and tennis shoes, Wilson swam until he was spotted by workers on an offshore oil platform, the Coast Guard said. The platform crew lowered a ladder but he was unable to lift himself out of the water.

A Coast Guard helicopter raced from Los Angeles and dropped a rescue swimmer, keeping Wilson afloat until a boat from the Channel Islands Coast Guard station arrived. He was finally pulled from the water at about 2 p.m., said Petty Officer 1st Class Kenny Cook, who was at the scene.

Wilson's son, Jeff, 26, is a personal trainer who was a past contestant on the reality television show "Survivor." He was the third person to be voted off the 10th installment of the reality television show in Palau after rolling his ankle.

Family and friends of Wilson, 55, of Santa Maria, said it was not typical for him to take the boat out alone, especially in stormy weather, and they were amazed he was able to survive in the cold water for so long.

"He now thinks that it was a very stupid thing, but he just wanted to make sure that everything was working right on the boat and then he was going to go right back into the harbor," said his mother, Joey Wilson.

She said her son told her some dolphins swam beside him at one point, but mostly he was alone in the open water.

"We are very grateful that he survived," she said.