RedactedNarrative: Vessel 1 and Vessel 2 were both travelling south on the Colorado River, just south of the Aquarius Hotel and Casino.  Vessel 2 was struck from the rear starboard side when vessel 1 made a left turn into them.  V2 subjects were both thrown from Vessel 2.  Operator2 sustained injuries to his back and a laceration to right elbow that required sutures.  V2 occupant sustained a broken right leg.  Operator of Vessel 1, did not sustain any injuries.