RedactedNarrative: Operator stated that he was the operator of MI-4772-BV on the West Pearl River. The vessel is a 15' WellBuilt flat boat with a 40 hp, hand tiller operated, Evinrude outboard. He stated that he had just entered the river from Davis Landing and was coming up on plane, headed down river, when his motor struck an unknown submerged object. Operator stated that he was ejected from the vessel over the starboard side and the vessel continued towards the East Bank of the river. The vessel then struck trees/debris near the shoreline and overturned. The vessel then submerged and drifted down river. It is unknown if alcohol or drugs were a factor in the incident. Operator stated that all PFD requirements were met and that he was unsure if he had the emergency cutoff lanyard attached. There were no injuries or fatalities in this incident. As of date the vessel has not been recovered.