On October 23, 1994, at 1715 central daylight time, a Gardner Sea Rey, N703SR, was substantially damaged while landing near Hartman, Arkansas. The commercial pilot was not injured. The passenger received serious injuries. Visual meteorological conditions prevailed for the personnel cross country flight. During a telephone interview the pilot reported the following information. The airplane was built by the pilot and certificated in the experimental category in 1993. It was capable of land or water landings. At 1545 the flight departed a private grass airstrip near Lavaca, Arkansas. During the flight, landings were performed on and off the water. Following takeoff from a road, the gear was not retracted. The next landing was on the Arkansas River near an island beach approximately 4 miles south of Hartman, Arkansas. The pilot circled the area in order to check for obstructions and "may not have retracted the the gear" for the landing. Touchdown airspeed was 50 to 60 mph. The airplane "decelerated to 0 knots within about one second as the nose came down and the airplane submarined." Subsequently the airplane stopped with the "nose 45 degrees down, and the tail and aft mounted engine in the air." The cockpit instrument panel was "destroyed and the switches for engine shutdown could not be located" in the submerged environment. With the cabin submerged, the pilot and passenger exited the airplane. The passenger was struck by the operating propeller. A fishing boat rescued the pilot and passenger. No mechanical malfunctions were reported. In the enclosed pilot report under "recommendations" he indicated "more effective use of landing checklist."