Authorities were trying Monday to determine how a 54-year-old Hoschton man drowned in a boating accident on Lake Lanier. Robert Armistead was aboard a 12-to-14-foot Jon boat when it capsized Sunday morning about 10 feet from shore near Aqualand Marina in South Hall County. “We don’t know if he stood up or reached over ... but the boat turned over and he didn’t have any personal flotation devices,” said Sgt. Kiley Sargent, Hall County Sheriff’s Office spokesman.