Jonathan McKnight, 30, died on August 12th on Tennessee's Class I-II Hiwassee River. A Chattanooga, TN newspaper reported that his "fishing tube" flipped below Appalachia Powerhouse. McKnight then floated head-down, despite his PFD, and drowned. His brother also flipped his tube, but was pulled upright by a friend. Fishing tubes have been implicated in several other deaths on the Hiwassee, and local outfitters warn that they are not suitable for moving water. There is no possibility of a quick release if the tube flips or becomes snagged.
http://www.georgia-outdoors.com/forum/showthread.php?t=33801