On July 16, 1999, at 0810 eastern daylight time, a Hiller UH12-C, N5317V, ditched into the Gulf of Mexico following a loss of engine power near Venice, Florida. The helicopter was operated by the commercial pilot under the provisions of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed for the local flight. The pilot and one passenger were not injured and the helicopter sustained substantial damage. The helicopter departed Venice, Florida, at approximately 0750. According to the pilot, the helicopter lost engine power while flying at 50 knots and 100 feet above the ocean during a flight to record video footage of the area. The pilot made an auto-rotation into the water. Both the pilot and passenger were immediately rescued by a nearby boat. Examination of the helicopter by the FAA found that the engine had sustained salt water contamination. Further examination established continuity throughout the engine and the drive train. Additionally, the magnetos sparked when rotated, there was oil/water in the crankcase, and there was fuel/water in the fuel tanks. The fuel shutoff valve control lock was inspected and it was found that it could be repositioned to allow movement of the control to the "off" position by a slight downward pressure on the control knob. The 245 pound passenger in the right seat was filming with a production type video camera and had brought several pieces of equipment on board. The aircraft was unsymmetrically loaded to the right and the doors were not installed on this flight. The passenger was wearing his seatbelt loosely to allow him to film directly out of the doorway. The fuel shutoff valve control knob is directly to the left of the passenger's left foot and approximately one inch off the floor. The exact position of the fuel shutoff valve prior to the accident was not determined.