RedactedNarrative: On Sunday, June 24", 2018 at approximately 2135 hrs, a boat accident occurred on the Coralville Reservoir near West Overlook Beach in Johnson County. The incident involved two vessels. The first vessel (Boat #1), a black and red Cobalt, had been operated by 16 year old under the supervision of 21 year old. The second boat (Boat #2), a blue and yellow Cobalt. The incident occurred when Boat #1 under the operation by the 21 year old made an evasive left turn to avoid colliding with Boat #2. As a result of the evasive turn, three women were thrown from Boat #1. One of those women was severely injured by the propeller of Boat #1.
  
   At the time of the incident, Victim was lying over the bow of the boat with her arms outstretched. 
  
  The boat smelled "like a brewery". There were red solo cups in the cup-holder next to the driver's seat and next to another seat
  
  The primary cause of the incident was determined to be operator inattention and improper lookout by the  primary operator of Boat #1. 
  
  -Boat #2 had a stern light but no navigation lights.
  -Boat #1 had navigation lights and stern light on.
  
  
  Through the course of interviews, as well as evidence at the scene, it was determined that there was alcohol use and marijuana use by some of the occupants of Boat #1 which may have impacted the ability of the operators to maintain necessary attention to the skills required to operate a vessel safely. According to Subject1 who was seated behind the wheel under Subject2's supervision, Boat #1 was "set" at a speed of 25 mph. During a re-enactment of the incident a speed of at least as close to create the forces incident, a speed of at least 25 mph was necessary to create the force required to throw a passenger from a boat similar in size to Boat #1. 
  Therefore, I concluded that the secondary cause of the incident was that the speed at which Boat #1 was travelling was too fast for the low-light conditions. A person operating a vessel after dark maintain a speed which allows for a safe and timely reaction to avoid obstacles in its path, including insufficiently lit boats.
  The tertiary cause of the incident was due to improper lighting on Boat #2. While the use of navigation lights may have increased the visibility of Boat #2, Boat #2's presence should have still been detected by those aboard Boat #1. Because Boat #2 was moving very slowly and was using the 360 degree white stern light (the only light required for use in stationary boats) Boat # 2 should have been visible to those aboard Boat #1 had they been sufficiently attentive and traveling at a safe and responsible speed. Even with lack of navigation lights, Boat #2 was visible to Corps Park Rangers on shore. the operator of Boat #2 was given a PBT at the marina with a result of .000.
  