On April 18, 2003, about 1945 Alaska daylight time, a tundra tire-equipped Piper PA-12 airplane, N3651N, sustained substantial damage when it nosed over after encountering ocean waters while taxiing for takeoff on a beach, about 50 miles south of Dillingham, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, and was en route to Dillingham when the accident occurred. The private pilot/airplane owner and the one passenger were not injured. Visual meteorological conditions prevailed, and a VFR flight plan was filed. The flight originated at the accident site, about 1940. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on April 19, the pilot reported that he was preparing to depart from a remote beach site, adjacent to the open ocean waters of Norton Sound. He said that while taxiing for takeoff, a very strong gust of wind pivoted the airplane's nose to the left, downhill and towards the ocean surf. The pilot said that he was unable to stop the airplane before the main wheels entered the ocean surf. The airplane subsequently nosed over and sank in the shallow ocean surf waters. The airplane sustained substantial damage to the left wing. The pilot reported that wind conditions at the time of the accident were from the northwest at 15 knots, with gusts to 20 knots. The pilot added that there were no preaccident mechanical anomalies with the airplane.