At about 1625 Alaska time, a Beech 18 crashed into shallow water in a tidal mud flat about one-half mile south of the Juneau International Airport, killing the pilot. The pilot was delivering building materials to a remote lodge. On the first flight, the airplane apparently was loaded with 73 bundles of wooden roof shakes. On the second flight, the airplane apparently was loaded with the remainder of the order, 77 bundles of roof shakes. Each bundle weighed about 56 pounds. Several witnesses consistently reported that the airplane departed runway 08 and climbed to about 200 to 300 feet above the ground. As the airplane approached the departure end of the runway, the nose of the airplane abruptly pitched up about 70 degrees and drifted to the right. The airplane continued to turn to the right as the nose of the airplane lowered momentarily. The landing gear extended, the nose pitched up again and the right wing dropped.