On June 3, 2001, about 0900 Alaska daylight time, a float-equipped Piper PA-18 airplane, N4468Z, sustained substantial damage during an aborted takeoff from a lake, located about 15 miles east of Minto, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight when the accident occurred. The airplane was operated by the pilot. The private certificated pilot, and the sole passenger, were not injured. Visual meteorological conditions prevailed. On June 12, 2001, the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) was notified by a Federal Aviation Administration (FAA) inspector from the Fairbanks Flight Standards District Office (FSDO), that the airplane had been damaged. The inspector reported that the pilot departed a lake with water in the airplane floats. The inspector said the airplane became airborne, settled on the surface of the lake, and landed hard. The inspector reported that a fuselage longeron was bent, adjacent to the left, aft, float attachment point. During a telephone conversation with the NTSB IIC, on June 13, the pilot reported that he was departing the lake, and the airplane became airborne in ground effect. The airplane would not climb, and the pilot said he aborted the takeoff. The airplane settled on the lake and hit hard. The pilot said he did not think the fuselage was significantly damaged. He said he unknowingly punctured the left float during a collision with an unkown object while preparing to depart the lake, and the float assembly had partially filled with water. On July 17, 2001, at 1210, during a telephone conversation with the pilot's mechanic, the mechanic reported that in addition to repairing the float, the left fuselage longeron was bent about 2 inches. The mechanic planned to cut the bent portion of the longeron out of the fuselage and install a repair sleeve.