RedactedNarrative: V1- Was operating the Polaris jet ski on the Kennebec River at a high rate of speed (58 mph) for approximately 30 minutes. Operator had never been in this section of the river and did not check the water depth at any location. Operator struck a submerged rock that was inches under the water at full speed. This caused both to be thrown over the handles bars of the jetski and into the Kennebec River. Passenger was transported by ambulance to the hospital in Waterville for neck pain.