RedactedNarrative: On October 31, 2015 Operator was operating vessel (FL6781ML) on the St. John's River between Lemon Bluff and Iron Bend.  At approximately 11:00am, Operator was heading South on the St. John's River in an area known as "Iron Bend".  It is a stretch of the river that requires somewhat of a sharp turn (right hand turn in this case).  Operator explained to me that he attempted to stay about 20 feet from the shore line because it is a sharp turn and it is difficult to see around the bend.  Operator observed a submerged log, and after passing the log he then hit an unknown submerged object.  The impact caused the motor to kick backwards into the boat while it was still running. The motor was only held on by brackets and was not bolted onto the transom. The skeg hit one of the occupants and the propeller hit Operator's right leg. Another occupant on the vessel who was on the bow pulled the safety cable to get the motor to shut off. 
  
  A few good samaritan on jetskis nearby approached them and helped them put the motor back on. Once the motor was put back on, Operator idled back towards Mullet Lake Boat ramp. The fire department had met them and rendered aid.  One individual (Operator) was treated by EMS, and one of the occupants was transported to Central Florida Regional Hospital in Sanford for his injuries.  
  
  During my investigation, I determined that improper lookout was the primary contributing factor.  Operator was operating his vessel at a reasonable speed (approximately 18-20mph), however, once he noticed debris in the water, it would've been appropriate to decrease speed and proceed with caution.  Based on my observations and investigation, I do not believe alcohol or impairment of the operator was a contributor to the collision.  
   
   