RedactedNarrative: Operator stated that it was really foggy and he could tell he was off-course so he began to slow down.  V1 struck 3 cypress knees and on the third one, V1 slid back and hung up between them and began to take on water rapidly.  V1 then began to roll and capsized.  All occupants were able to safely get away from V1.  They along with some friends were able to get V1 flipped over and back above the water.  Due to going underwater while running and remaining underwater for an extended about of time the mud motor is a total loss.  Also the motor handle was broken completely off during the incident.