RedactedNarrative: On July 18, 2016 at approximately 1142 hours Ranger and I responded to a report of a sinking vessel at the Wahweap main launch ramp. At approximately 1144 hours I arrived on scene and located houseboat "Why Knot", a 75' aluminum full hull Bravada houseboat, on the Eastern courtesy dock of the Wahweap main launch ramp. The vessel appeared to be taking on water.
  
  OPERATOR stated the following:
  At approximately 1030 hours he was driving houseboat "Why Knot" from Gunsight Bay, where they had been camped, en-route to Wahweap Marina slip when they turned into Warm Creek Bay on the Northern end from the main channel. He was following several other boats, at a safe distance. Upon entering the mouth of Warm Creek Bay he had difficulty seeing due to sun glare on the water. The vessel struck a submerged rock shoal with the front middle of the hull. He was able to avoid overrunning the shoal with the rear of the vessel. The vessel began taking on water. He was able to continue driving the vessel to the Wahweap Main launch ramp. Five people were on the vessel at the time of the accident. No one on the vessel had consumed alcohol. He is one of the time share owners of the vessel. 
  
  Property Damage:
  While speaking with OPERATOR Lake Powell Marina staff were on scene actively pumping water out of the hull of the vessel and attempting to load the vessel onto a trailer. The stern of the vessel continued to take on water. The entire aft deck of the vessel was submerged with water entering the cabin of the vessel.
  At approximately 1220 hours Lake Powell Marina staff were successful in placing the houseboat on a trailer and removing it from the water. Ranger photographed the vessel. A photo log is included with this report.
  
  Observed damage to the vessel consisted of an approximately 24" x 6" gash to the underside aft the center of the keel that pierced the hull, an approximately 18" x 2" gash to the underside aft center of the keel that pierced the hull, an approximate 24" x 6" diagonal scratch to the underside aft starboard center of the hull, and an approximately 36" x 6" scratch to the underside center starboard side of the hull. The vessel was also inundated with water in the aft 1/4 of the vessel including the engine compartment, cooler compartment, aft kitchen area, and the aft swim deck area. The hull was filled with approximately 3000-5000 gallons of water. Other damage to the submerged area likely resulted as a result of water damage and or inundation.
  
  Conclusion:
  As a result of my investigation I have determined the primary cause of the accident as follows in order of occurrence and importance:
    1) Operator inattention: the rock shoal at the mouth of Warm Creek Bay is a well-known hazard marked on navigation charts and lake maps. The shoal is also clearly marked with a hazard buoy in the vicinity of the shoal.
    2) Restricted vision: the operator of the vessel (OPERATOR) was unable to see hazards in the water due to environmental conditions, sun glare.
  
  END OF REPORT.