While V1 was beached at Sandy Beach in Lake Mead NRA, monsoonal storms occurred causing the vessel to begin to dislodge from the beach.  (owner) stated that he believed he put the vessel in "Neutral" to attempt to secure the vessel to the beach.  Subject jumped into the water from the rear of the vessel and was "sucked under" the boat due to the motor being in "Reverse".  subject emerged from the water with lacerations to both legs as a result from the impact from the vessel''s propellor.
Henderson                     