On March 2, 2018, about 1625 central standard time, an Aero Commander 100-180, N3733X, sustained substantial damage when it hit a tree during a forced landing to a field after a total loss of engine power near Deport, Texas. The pilot received minor injuries. The airplane was owned and operated by the pilot under the provisions of the 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time of the flight, which was not operated on a flight plan. The flight departed from the Cox Field Airport (PRX), Paris, Texas, about 1600 on a local flight. The pilot reported that he attempted to fly his airplane the day before the accident, but he had maintenance problems and decided not to fly. He reported that there had been an extended period of rain in area and his airplane was parked on the airplane ramp during that time. During the preflight inspection, he sumped the fuel twice with about 4oz of water in the samples. The airplane had not been flown since January 28, 2018, and the battery was "completely dead." The battery was charged enough to get the engine started and he taxied to the run-up area. During the magneto checks, the engine "died," and he needed assistance to get the engine running again. While waiting for the assistance to arrive start the engine again, he decided to recheck the fuel system. He reported that he sumped thirty 8oz bottles of water from the fuel system before he saw clean blue fuel. After getting the engine started again, he taxied back to the ramp and tied the airplane down. He reported that the right wing was sloping to the west (right wing down). On the day of the accident flight, a mechanic charged the battery. During the preflight inspection, the pilot sumped the fuel system and found a small amount of water during the first check, but it was clear on the second check. During the run-up, the airplane operated normally, and he departed. The pilot reported that after flying for about 25 minutes, he executed a left turn at a 45° bank angle. He stated that about 1 minute after leveling off at 500 ft above ground level, the engine sputtered once and stopped producing power. His attempt to restart the engine was unsuccessful. He executed a forced landing to a field but was unable to stop the airplane before hitting trees during the landing roll. The pilot reported that on the day of the accident, he purchased gasket material and made "additional gaskets for the fuel cap hoping that if water got in that way this might stop it." He reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. An FAA inspection of the airplane's filler neck and cap showed large amounts of rust.