RedactedNarrative: Operator said he was northbound in main channel just south of 7th Street Boat launch. Operator estimated speed was around 15mph and said boat was not on plane. Operator said he was trying to pitch bow up to drain rainwater to rear while running bilge pump. 
  
  Operator said vessel struck unknown sunken hazard. Operator described position of boat to be 0.5 miles south of 7th Street launch, and said collision occurred between red and green wing dam marker buoys. Operator said closest red buoy was 100 yards to the east off starboard side. After collision vessel began to take on water. Passerby towed vessel to sandbar before vessel was returned to 7th Street Boat launch by La Crosse Fire Boat.