RedactedNarrative: On September 6, 2018 at 1630hrs I received a call for service from the MT HWY Patrol Dispatch Great Falls D1 concerning a boating accident in Great Falls on the Missouri River.  I responded to 3000 Lower River Road and contacted two witnesses associated with the incident.  The men described what took place and showed me the vessels involved near a dock on the river just behind units 2-5.  I observed a PWC floating in the water about 20 feet down river from a docked and red tarped v-hole vessel.  According to the witness they heard a large boom and then observed the PWC floating in the water with smoke rolling out (later determined to be vessels broken fire extinguisher). They ran down to the dock and found the operator of the vessel laying in the water knocked out from hitting the back of the docked vessel at what they believed to be a very high rate of speed.  They retrieved the operator of the PWC from under the V-hole docked vessel.  The subject was badly injured from blunt force trauma, they observed a very large cut/gash on the right side of his head.  The subject was wearing a life jacket but was floating face down.  The witnesses got subject out of water and determined he was now breathing.  A third witness mowing a lawn nearby had already dialed 911. .  I then photographed the scene and took some measurements.  I received a call from Sergeant Warden who responded to the hospital to assess the operators condition and attempt an interview.  
  Description of events:
  At approximately 1530HRS the operator of the PWC (MT2125AY) was traveling south (upstream) on the Missouri River (departed from Broadwater Bay).  The operator took the middle channel of the river between two islands.  The river bends west when you pass those islands heading south upstream.  If you do not turn south west (right) the trajectory puts you on a collision course with the docked vessel (MT3203AY) located at the accident scene (N47.47572000, W111.31355600).  I made note that at this time of day (approximately 3:30PM) when heading south on the river the sun could be a consideration in the accident, however a pair of prescription sunglass were found at the scene (on the back of the docked vessel). I also made note the docked vessel is black, 32 feet in length and was cover by a bright red canvas cover easy to see under clear daylight conditions.  If the dock and vessel was not there the subject had approximately 21 feet of shallow water prior to hitting land.  The PWC (MT2125AY) contacted the docked vessel (MT3203AY) in the transom at a slight angel, the docked vessel being at a right angle to the shore line, the PWC hit the dock then contacted the back right-hand corner driving the docked vessel forward approximately 7 feet (see photos and drawing) striking the handle bar of parked PWC (MT7038BC) causing minor damage to the left handle bar grip. During the investigation I checked the throttle and the steering controls on MT2125AY.  Everything appeared to be in working order.  When the driver was pulled out to the water he was wearing the tether cord for the kill switch which properly shut off MT2125AY after the collision.  
  On September 7, 2018 I met with Sergeant who explained that he met with operators (driver) girlfriend again last night to deliver his prescription sunglasses found at the scene. During that conversation she stated that the operator has been taking prescription medication for depression for the past three months. We will attempt a second interview with the operator when his medical condition improves.   
  On September 10, 2018 I called the operator and learned the following:
  1.	He came up the far west channel not the middle as stated before.
  2.	Does not remember much after entering the big open area.
  3.	Was intending on turning left and head back down the east channel back to Broadwater Bay to meet his another individual.
  4.	Stated he was going full speed (40-50m/hr.)
  5.	Stated he remembers hitting a wave and then thought he may have passed out.
  6.	Stated he felt light headed that day.
  7.	Stated the water was like glass that day. The wave could have been from him turning.
  8.	Stated he has asthma and made note that his PFD was tight, and he thinks he just passed out.  In his past he has had fainting problems.
  9.	Stated he has been under a lot of pressure lately and went down to the river to relax. He was scheduled for court the next day concerning a complaint from his X wife.
  10.	Stated he does not have insurance on his PWC.
  During the conversation I asked the operator about taking medication and he explained that he has been on a light dose of medication for about three months concerning depression.  He has an appointment at 1pm today, September 10, 2018, to meet with a medical professional concerning his depression.  I asked for his Doctor's name and phone number and for the operator to call back after the meeting to determine if the medication could have caused him to pass out just prior to the accident.  I later spoke with (Great Falls Clinic) and determined that the medication could not have played a role in the accident as described by the operator. 
  I called the owner of vessel (MT 3203AY) and explained that I spoke to the operator and discovered he did not have insurance on is PWC.  the owner of vessel (MT 3203AY) stated that he has already spoke with the operators mother about that issue.  The owner of vessel (MT 3203AY) explained that he was turning in a claim to his own insurance company concerning the damage to his boat.  I asked about any security cameras on any of the homes near the accident scene.  The owner of vessel (MT 3203AY) stated he was certain there were none in his immediate neighborhood.
  