The 17-year-old boy built a one-person watercraft with instructions he found online. He ventured out into the water near Grimsby without a life jacket when he encountered rough water. He was thrown into the water.
A woman saw he boy's boat and called 911 while her husband kayaked out to find the boy. He paddled out with an extra life jacket and a rope, and took him to shore.
The teen was taken to West Lincoln Memorial Hospital to be treated for exposure.
Hamilton Police Marine Unit were called to the scene but left after word of the boy's rescue spread.
Hamilton police called it a "local example of dangers of cold water and not wearing personal flotation device," and that the "couple saved this boy's life."