Jim Dreyer, 49, an experienced long-distance swimmer from Byron Center, climbed into the water at 8:30 a.m. EDT and started his swim, which he said he expected to take about 30 hours, while pulling two inflatable rafts filled with a total 2,000 pounds of bricks, Mlive.com reported.
Dreyer said his feat is aimed to benefit Habitat for Humanity of Michigan.
"The conditions out here are great," Dreyer said before starting his swim. "The water's flat and the temperature is good. I couldn't ask for any better conditions.
"I can see the whole skyline of Detroit right now and that is really going to help. I figured I'd be able to see the [General Motors] tower, but not this much. We may not have that the whole time but right now it's really going to help motivate."
Dreyer said his goal was to arrive Tuesday at Belle Isle Beach in Detroit.