Operator was operating his 23' Mastercraft open motorboat just north of East Channel Bridge (Mercer Island) on Lake Washington.  He was towing  a group of juveniles on a large water tube behind his boat.  The boat was on plane and as Operator made a wide turn, the water tube hit a wake generated by the vessel.  This wake caused the tube to bounce and two juveniles on board lost contact with the tube and bounced in the air.  When they landed back on the tube, one juvenile landed on top of  victim knocking the wind out of him.  None of the tubers fell off the tube and all remained aboard the tube.  Operator pulled the tubers aboard his boat and returned to shore at the Mercer Island boat launch.  Once ashore, victim began complaining of lower back pain, so operator contacted the Mercer Island FD and Mercer Island PD.

Victim was treated at Overlake Hospital for a contusion to his back, some bruising and was wearing a back brace as a precautionary measure.
Mercer Island                 