(Near North Plains, OR)  --  Authorities say a medical event may have led to the drowning of a 76-year-old Aloha [[ ah-LOW-uh ]] man in a private lake near North Plains.  The Washington County Sheriff's Office says Charles Merrill fell out of his boat yesterday and into the one-acre lake, located off Northwest Braga Road.  First-responders found the boat had capsized.  Merrill's body was found around five o'clock yesterday afternoon.