On May 7, 1994, at 2040 central daylight time, a Hiller UH-12B helicopter, N6417V, was substantially damaged during landing near Crystal Beach, Texas. There was no flight plan filed for the local sightseeing flight and visual meteorological conditions prevailed. Neither the commercial pilot nor the two passengers were injured. According to the pilot, the aircraft lost partial power during initial climb after takeoff. The pilot stated that he felt that landing straight ahead would have been hazardous and he elected to turn down wind and attempted to maneuver back into the wind at low altitude. The pilot reported that an excessive rate of descent developed prior to touchdown. The helicopter touched down sideways, rocked on the skids, and rolled onto its left side. Investigation revealed no evidence of pre-accident mechanical failure or malfunction within the engine or its accessories. However; an analysis of fuel taken from the system revealed that it was contaminated with water.