RedactedNarrative: V1 WAS TRAVELING NORTH ON THE COLORADO RIVER WHEN THE OPERATOR SAYS HE LOST POWER, CAUSING HIM TO LOSE STEERING CONTROL.  V1 CONTINUED INTO THE SHORE, STRIKING THREE SUBJECTS ON THE SHORELINE CAUSING INJURY.  ONE FEMALE JUVENILE WAS LATER TRASPORTED BY AIRCRAFT TO LAS VEGAS FOR CRITICAL INJURIES TO HER HEAD.  ONE FEMALE JUVENILE SUSTAINED A BROKEN TAILBONE AND AN ADULT FEMALE COMPLAINED OF UNKNOWN INJURIES.