RedactedNarrative: Unit 1 was traveling up stream when the motor hit a submerged object resulting in the motor being jerked from operator's control. Subject fell out of the left side of the boat and the passenger fell over the left side of the boat.  The Operator was able to grab the kill switch and cut the motor off. Unit 1 then took a hard right hand turn back down stream and went over the top of passenger resulting in the prop cutting her head. Operator was able to get to the boat and help the passenger back into the boat.  Unit 1 made it back to Little Hell Landing and I (Officer ) followed subject to the hospital. The injured party had a few staples and stiches and is doing well.