RedactedNarrative: Vessel 1 was in operation downstream with three persons on board when Vessel 1 struck a submerged object causing Vessel 1 to turn sideways and become stuck against the submerged object.  The high water and current against Vessel 1 resulted in a capsizing with all Occupants aboard being ejected into the water.  All parties were wearing PFDs at the time of the incident and swam to a nearby sandbar without injury.  One of the Occupants then swam back across the river and walked to a local road where he flagged down assistance; the remainder of the Occupants were subsequently rescued from the sandbar.  Following the rescue, Vessel 1 was unable to be located.