The owner/builder/pilot of the home built aircraft and a passenger (a foreign visitor) were on a local flight along a beach area. The purpose of the flight was for the visitor to take some video tape footage with the video camera that he took along. Witnesses, including a friend of the visitor, saw the aircraft flying slow at an altitude of approximately 100 feet above ground level and 300 yards from the beach. They reported that the aircraft was flying parallel to the shoreline when it pulled up in what appeared to be the initiation of a climb. At about that time, the aircraft suddenly fell off on the right wing and rolled to an inverted, nose low attitude. Reportedly, the aircraft had rolled back to a wings level attitude, and was recovering from a dive, when it impacted in the water. Witnesses reported that the engine was operating at a high RPM (screaming) when the aircraft crashed in about a 45 degree nose down attitude. An exam of the wreckage revealed no preimpact failures.