On September 29, 1995, about 1650 eastern daylight time, a Beech D50E, N9351Y, registered to an individual, made a forced landing in a field near Okeechobee, Florida, while on a 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft received substantial damage and the private-rated pilot received minor injuries. The flight originated from Lantana, Florida, the same day about 1600. The pilot stated to Sheriff's Department deputies that he did a fly-by of the Okeechobee Airport to do a feathering check of the right propeller. While at an altitude of 1,500 feet the right engine was shutdown and the propeller was feathered. When he unfeathered the propeller the engine would not start and he could not feather the propeller again. The propeller remained at a low pitch position and was wind milling. He was unable to maintain altitude and made a forced landing in a field. Witnesses stated that upon departure from Lantana, the pilot feathered the left propeller and did a fly-by of the airport. The left propeller was observed to start rotating again and the aircraft flew off to the west. A witness at the Okeechobee Airport stated the pilot contacted him on the radio and asked that he step outside and see if his right propeller feathered properly. When he stepped outside he observed N9351Y flying at an altitude of 1,000 feet. The pilot feathered the right propeller and it appeared to feather properly. The witness then went back inside his office. Post-accident examination of the aircraft by an FAA inspector and a representative of Lycoming engines showed no evidence to indicate precrash malfunction of the right or left engine assemblies. The blades of the left and right propellers were below the mechanical latch position and the mechanical latches were extended. The left propeller blades were curled and bent aft. The blades on the right propeller were bent aft and were not curled. The propellers and propeller governors were removed for testing. Each propeller operated normally when placed on a test stand. The mechanical latches, which retract due to centrifugal forces at about 1,000 engine rpm, were free to retract and extend. Each propeller governor operated within manufacturer's specifications. See attached inspector statements.