Cries for help rang out from Midland Bay around 8:30 Tuesday evening, which prompted a citizen to alert the Ontario Provincial Police, who reported a man was in the water next to a sailboat that was attached to another vessel, about 200 metres off the shoreline from Gawley Park.
Three officers were first on the scene and commandeered a small aluminum boat from a nearby residence and drove out to the sailboat.
Police say they found an exhausted man in the water without a life jacket clinging to the second vessel.
He was removed from the water and transported by paramedics to a local hospital and later released.
Police say the 61-year-old from Brockton had been in the cool water for over an hour, and it had reduced his ability to physically move.
"Wearing a life jacket while on the water can help make a difference in the outcome of these situations as Georgian Bay is a big place and self-rescue may be your only option," police stated in a news release.