RedactedNarrative: Operator was headed towards the owner's pier and were about 100 yards from the pier when the incident happened.  There were four children between the ages of 8 and 12 sitting on the bow without any PFD's.  The boy on the starboard most side fell off of the bow and went between the pontoons.  No warning was given to the operator by anyone on board.  The operator felt the prop hit something and then head the boy scream.  The prop hit the boy's left leg causing lacerations.  The boy was brought back on board and transported to the pier.  At the pier he was stabilized by medical personnel and then transported to the hospital.