RedactedNarrative: OPERATOR reported that they had just departed a beach in Mountain Sheep Canyon where they had overnighted. As the operator was maneuvering the vessel out of the canyon, it struck a large rock formation lying approximately 1 foot under the waterline. 
  
  The vessel was driven up onto the formation to the extent both of its pontoons were atop the rock. The skeg was broken off the starboard outboard engine, and all three blades of the prop were damaged. The port engine and prop appeared to be intact. The starboard bilge pump was running and a continuous stream of water was exiting the bilge outlet. There were no injuries aboard the vessel. The vessel appeared to be secure atop the rock formation with little chance of it being displaced by wind or action. I instructed the parties to put on life jackets if the vessel slipped off the rock and to try and beach the vessel.
  
  OPERATOR stated that because of the low light conditions present at the time of day (around 0600 hours mst) that he was unable to see the color change characteristic of shallow waters on Lake Powell. Thus, he was unable to see the rock formation ahead of the vessel and drove the vessel on top of it.
  
  I ensured that NPS dispatch had contacted Aramark boat rentals. An Aramark service vessel was reported to be in route upon my departure from the scene.