RedactedNarrative: VESSEL 1 WAS TRAVELING SOUTH DOWN MILL CREEK AND CAME UP TO A TREE THAT WAS HANGING OVER THE CREEK.  THE TREE HAD A LIMB ABOUT FIVE INCHES IN DIAMETER HANGING DOWN INTO THE WATER.  THE MOTOR SHUT OFF BEFORE REACHING THE LIMB.  THE VESSEL CONTINUED STRIKING THE LIMB CAUSING THE VESSEL TO TURN SIDEWAYS.  WATER BEGAN TO RUSH OVER THE SIDE OF THE VESSEL DUE TO OCCUPANTS SHIFTING THEIR WEIGHT TO ONE SIDE CAUSING THE VESSEL TO CAPSIZE.  NONE OF THE OCCUPANTS USED A LFD.  ALCOHOL WAS PRESENT IN THE VESSEL AT THE TIME OF THE ACCIDENT BUT IT WAS NOT A CONTRIBUTING FACTOR.