The Operator of Vessel 1 was towing a tuber; the Operator then shut the motor off and Vessel 1 was drifting.  As Vessel 1 coasted to a stop, the slack in the tow line tightened and snapped the tube up, causing the Victim's knee to strike his head and temporarily knocking the Victim unconscious.  The Victim was transported to the hospital where he was treated and released.
Bethel                        