On July 23, 1996, about 2100 Alaska daylight time, a float equipped Cessna 182 airplane, N2831F, sustained substantial damage when it collided with terrain during an attempted takeoff from the Kustatan River, located approximately 30 miles west of Nikiski, Alaska. The private certificated pilot received minor injuries; the two passengers aboard were not injured. According to the owner of the airplane, who occupied the right front seat at the time of the accident and is also a certificated pilot, the pilot was attempting to takeoff upstream in a fairly narrow portion of the river. The airplane accelerated normally, and the floats were planing, "on the step", when the airplane was required to negotiate an approximate 30 degree right bend in the river. The airplane's owner said he thought the pilot may have entered the bend at too high a speed, and therefore was unable to keep the airplane centered in the river channel. The airplane skipped to the left, and when collision with the bank appeared imminent, the pilot pulled back on the yoke in an attempt to become airborne. The airplane momentarily left the water, but the left float struck the top of the bank. The airplane continued about 100 feet inland, where it collided with trees and brush. Subsequent conversations between the NTSB investigator-in-charge and the pilot disclosed essentially the same information. The airplane's owner, and the pilot, both of whom are certificated aviation mechanics, said there was no preimpact mechanical difficulties with the airplane that would have caused or contributed to the accident.