At 1406 Central time, the private pilot reported engine failure and ditched one mile off Panama City Beach, Fla. Visual conditions prevailed. The airplane was substantially damaged; the pilot was fatally injured and his passenger received minor injuries. According to the pilots mechanic, the pilot contacted him at approximately 1219, and requested that he prepare his airplane for a short flight. Over the next 1.5 hours, the pilot, his mechanic and line personnel experienced difficulties involving a dead battery, underinflated tires and substantial amounts of water in its fuel tanks. The pilot arrived at the airport and, after another jump start of the airplane, boarded along with his passenger. The head lineman jumped the airplane again and the engine started. At 1345, the pilot contacted ATC, requesting to depart VFR to the west. After taxiing to the runway without a runup, the pilot was cleared for takeoff at 1348. At 1403, the pilot contacted the tower and advised the controller that he “lost engine power and was attempting to restart the engine.”