The pilot was departing from a lake in a float-equipped airplane with passengers and hunting gear. He stated that the departure plan was to get the airplane on step into the wind, and then turn lengthwise and depart with a crosswind. During the takeoff run, the airplane “used a fair amount of water on step” before a gust of wind lifted the right wing. In an effort to correct for the gust, the pilot lowered the wing and added power, but the airplane was too close to the bank of the lake, which resulted in an impact with terrain and substantial damage to the fuselage, right wing and tail. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation. In the recommendation section of NTSB Form 6120.1, the pilot stated that a step turn departure may have been more appropriate.