The operator was operating the motorboat owned by another person.  The owner is a realtor and had just sold the operator a home on the tar reservoir.  The operator and The owner were cruising on the lake in the late evening to look at other houses and to see the reservoir.  The owner had asked The operator if he knew how to dock a boat and he said that he did.  She allowed him to operate the boat.  The operator was operating the boat in the vicinity of the bend of the river bed boat ramp, headed back toward the sapony creek area of the lake.  While talking,  The operator looked up and saw that they were about to hit the rocks near the bridge along the bend of the river road.  As he reached up to throttle back the boat, the boat struck land, then traveled approximately 13 feet up the rocky embankment and came to rest on the guard rail of the road.  None of the passengers were wearing pfds.  Alcohol was not a factor.  The operator and one passenger were seen by paramedica at the scene and released.  The owner was airlifted to pitt memorial for medical treatment of serious injuries.  Operator inexperience and inattention and his being unfamiliar with lake caused the accident.