After thirty minutes of flying, the pilot noticed the oil pressure was zero. The pilot reported the problem to Miami radio and advised them he was returning to the airport. About five minutes later with reduced power, the engine stopped. The pilot advised Miami radio of his intention to make an emergency landing on the water close to a large ship. After landing, the plane floated for approximately thirty minutes and then sank. The pilot reported being in the water for fifteen minutes before being rescued by the U.S. Coast Guard. The airplane was not recovered.