THE PILOT BECAME LOST OR DISORIENTED, ALLOWING THE AIRPLANE TO GET OFF-COURSE/OVER WATER; AND LOSS OF ENGINE POWER FOR AN UNDETERMINED REASON. FACTORS RELATED TO THE ACCIDENT WERE: CLOUDS AND HIGH WINDS ASSOCIATED WITH THE PREVAILING TROPICAL STORM, THE PILOT'S IMPROPER EVALUATION OF THE WEATHER CONDITION, THE LACK OF RADIO OR NAVIGATION EQUIPMENT, AND THE POOR LIGHT CONDITIONS (DUSK) AND LARGE WAVES/SWELLS IN THE FORCED LANDING (DITCHING) AREA.