On September 11, 1993, at 1605 Alaska daylight time, a float equipped Cessna 206 airplane, N9707Z, registered to and operated by Fishing Unlimited Lodge of Port Alsworth, Alaska, crashed after takeoff and nosed over on a mud bar. The business flight, operating under 14 CFR Part 91, was departing a slough in Swikshak Bay located on the west side of Sheilikof Straits, and the destination was Port Alsworth. A company flight plan was in effect and visual meteorological conditions prevailed. The commercial certificated Pilot-in-Command and three passengers received minor injuries, and one passenger received fatal injuries. The airplane was substantially damaged. According to the Pilot-in-Command, he was taking off down river on the slough and there was no perceptible wind on the surface of the slough or the surrounding lakes. He stated he lifted off at 50 to 55 knots and the airplane began to settle shortly after lift off. He attempted to keep the airplane aligned with the channel of the slough so he would not hit a mud bar. The airplane touched down in shallow water, hit a mud bar, and nosed over. The Pilot-in-Command stated that two other company airplanes took off just before. They encountered no problems and each stated the wind was negligible. The airplane crashed in the slough and was resting in very shallow water. The Emergency Locator Antenna was located on the top of the airplane. The antenna broke off when the airplane nosed over. The airplane's radios were immersed in water and would not operate. The passenger who was fatally injured was seated in the rear most seat of the airplane. The distance between the cabin floor and the cabin ceiling decreases rearward through airplane. An NTSB Investigator seated in the rearmost seat had only 2 inches of clearance between the ceiling and the top of his head. The autopsy results showed the passenger received a basilar skull fracture. According to the Pilot-in-Command, he performed CPR on the passenger on three different occasions while simultaneously attempting to radio for assistance. There were three other passengers who received only minor injuries.