Flight Details
The pilot began the flight with approximately four hours of fuel, despite a planned duration of one hour. About 50 minutes into the flight, while over open water at an altitude of less than 1,000 feet, the right engine began to experience a strong vibration. The cause of the vibration was not determined.
Engine Problem
In response to the vibration, the pilot shut down the right engine. The vibration continued, though with less severity, after the shutdown. The pilot reported that the vibration was sufficiently strong to prevent attaining enough power to maintain level flight on the remaining engine. Consequently, he could not maintain altitude or reach a suitable landing area.
Ditching
The pilot performed a ditching on "glassy water" conditions. The airplane sank in approximately 150 feet of water and was not recovered.