RedactedNarrative: Vessel one was traveling through the Inlet Bay Channel at Horsetooth towing three people on a tube. A female fell off of the tube (victim) and the operator of V1 circled back to pick her up. It was believed that the operator accidentally hit the throttle in reverse which caused the victims leg to be pinched severely by the prop. It was believed that the prop was going in reverse as the victims leg was not cut but pinched, due to the blunt back edge of the prop blade.  The operator said he did not know the prop had cut the victim until he heard a loud scream and a thud, and the operator immediately turned the boat off and pulled the victim into the boat.