According to the pilot, after landing in a canal where aircraft were prohibited from landing, he was directed by law enforcement personnel to depart in a northwest direction. The pilot subsequently performed a "normal takeoff," and after becoming airborne, the airplane "pulled to the right," and continued to climb with a nose-high attitude. The nose then dropped and the airplane impacted the water. The pilot ascertained that the airplane must have struck an obstacle in the water during the takeoff, after noticing a puncture hole in the right float. Examination of the airplane by a Federal Aviation Administration (FAA) inspector did not reveal damage consistent with an obstacle impact, detailed maps of the canal did not reveal any exposed rocks along the take-off path, and the nearest obstacle would have been 4 feet below the water line. The FAA inspector also viewed a video of the accident flight, which showed the airplane "taking off in a level attitude, then commencing a shallow bank right hand turn." Initially, the airplane climbed, but as the airplane's angle of bank increased, the nose pointed down to below the horizon, and the airplane descended until impact. The pilot did not report any preexisting mechanical anomalies with the airplane.