13K is a tough level for the inexperienced
Several years ago we were involved in a very similar situation at almost exactly the same water level in Westwater. Luckily ours had a better outcome, not because of anything the victims did but simply because of dumb luck. We had been sitting at the bottom of Funnel after one of our team swam out of Staircase when first a duckie, with an older man and young child flipped in Funnel and then immediately following that a raft with a 30 something father and two even younger children flipped in the same place. We had three children, two of whom were wearing adult life jackets and two adults in the water. None wore any cold water gear (and it was really cold because of snowmelt) and the only thing that saved them was some quick throw rope work, a bit or rock climbing by one member of our crew to get to a stranded six year old and some quick work by two of us jumping in out boats (one of whom had never run Westwater before but agreed to follow my line (and would have wandered into the hole in Surprise if he hadn't)) and chasing the 65 year old all the way to Skull where he luckily washed into the eddy just above the drop on river left. The duckie made it all the way through Last Chance and the raft made it to just above the Cisco take out.
So word of warning to all, at 13K the inexperienced and unprepared are truly taking their lives in their hands in Westwater. Self rescue is difficult and boats (and people) will flush through several rapids if not rescued quickly. Luckily for this group a rafting party from Moab had stopped at Skull and another party came down that had room for the three children and one adult who were stranded with our team at Funnel. This allowed us to get them off the river, and also warmed up because between all of us we had enough extra clothing to dress everyone in proper cold weather gear. Also, at Funnel Falls in the canyon it takes some 5.6 rock climbing just to climb out so without boats, cold and shivering in cotten clothes these people even had they self rescued would have been stranded.