Thomas Drewek, 44, wasn't wearing a life preserver when the Lake Express ferry spotted him on its way from Milwaukee to Muskegon, Mich., according to the Coast Guard.

"Just by chance, the Lake Express saw him," Petty Officer Robert Napp said.

A wave caused his powerboat to capsize, and he wasn't able to radio for help, Napp said. He was the only one on board.

Drewek, who was sailing out of the Milwaukee suburb of Oak Creek, spent one hour 45 minutes in the 65- to 70-degree water, Napp said. In those conditions, he could have survived for about 36 hours, according to the Coast Guard.

The ferry got him on board around 6:30 a.m. and headed back to Milwaukee, where he was hospitalized. Drewek wanted to walk off the ferry by himself, but paramedics would not let him, Napp said.

The Lake Express ferry makes three round trips between the two port cities daily during the summer.