In the summer of 1962, Frank Brown and "Big Willie" George launched a 133-pound motorboat--with no motor--into the San Marcos River and headed for the Texas coast. Over the next three weeks they paddled downriver, wrestling through log jams and fighting off mosquitoes on their 337-mile journey to Corpus Christi. The following year, Brown staged a canoe race that followed the same route, billed as "The Texas Water Safari--The Toughest Boat Race in...