On July 11, 1997, about 1700 Alaska daylight time, a tundra tire equipped Piper PA-18 airplane, N1961P, crashed during a precautionary landing about 17 miles west of Talkeetna, Alaska. The airplane was being operated as a visual flight rules (VFR) local area personal flight when the accident occurred. The airplane, registered to and operated by the pilot, sustained substantial damage. The certificated commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at Merrill Field, Anchorage, Alaska, about 1540. On July 14, 1997, at 0950, the pilot reported in a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), he was in cruise flight at 1,200 feet above the ground (AGL). He switched fuel tanks from the left tank to the right tank. The engine began to run rough, and lose power. Emergency procedures failed to remedy the engine roughness, and the pilot selected an open field area for a precautionary landing. The terrain was soft, and during the landing roll, the airplane nosed over. The airplane received damage to the right wing lift strut, the right wingtip, and the tail assembly. Aircraft recovery personnel reported on July 21, 1997, that during the removal of the airplane, it was turned onto its landing gear. A check of the fuel tanks revealed about 1 1/2 cups of water in the right fuel tank. Water was not found in the gascolator or the carburetor. After the propeller was replaced, the engine was started, and developed 2,700 RPM. The pilot reported that the weather conditions at the time of the accident included broken clouds at 1,500 feet AGL, with light rain.