The propeller couldn’t be feathered following an engine failure. The aircraft lost speed and altitude and had to be ditched before it could reach the airport. PROBABLE CAUSE: pilot in command – attempted operation w/known deficiencies in equipment personnel – maintenance,servicing,inspection: inadequate maintenance and inspection powerplant – ignition system: ignition harness,shielding powerplant – propeller and accessories: hydraulic pitch control mechanism pilot in command – failed to follow approved procedures,directives,etc. miscellaneous acts,conditions – improper emergency procedures FACTORS: systems – electrical system: generators/alternators systems – electrical system: batteries complete power loss – complete engine failure/flameout-1 engine emergency circumstances – forced landing off airport on water