The Coast Guard says someone reported the situation in the lake a few miles east of Toledo on Sunday. A rescue boat crew from Toledo and a helicopter crew from Detroit located the men, who were holding onto the stern of the boat.
They were in the water for more than an hour before being hoisted into the helicopter and taken for medical care.
The helicopter crew's co-pilot says the men were smart to wear life jackets, stick together and remain close to the boat, making them easier to spot from the air.
Officials didn't immediately identify the rescued boaters.