Nearly 12 hours later, William Durden's wife called authorities worried. He hadn't come home. His 22-foot boat was found in the mangroves near St. Martins Keys overnight.
The next morning, Coast Guard authorities located Durden about 15 nautical miles southeast of Aripeka. According to the U.S. Coast Guard Southeast's Twitter account, he'd been treading water for 20 hours without a life jacket.
A helicopter crew flew to the scene and sent a rescue swimmer to get Durden. He was safe at 10:39 a.m., almost exactly 24 hours since he had left home.
Durden, from Reno, Nev., was taken to the Coast Guard's Air Station Clearwater for medical assistance. He checked out with no concerns.