On November 17, 2018, at 1300 mountain standard time, an experimental Scottish Aviation Series 100 MDL 101 airplane, N82696, was substantially damaged when it was involved in an accident near Lake Pleasant, Arizona. The pilot and passenger received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that after takeoff he departed to the north toward a lake for a sightseeing flight. While over the lake at 700 ft above ground level (agl), the engine started to shake and subsequently lost power. The pilot attempted to restart the engine by turning the auxiliary fuel pump on and he dove the airplane toward the water in hopes of the wind milling propeller would help in restarting the engine. The engine started but the pilot estimated that it was only producing about 50% power. The pilot noted a glider port just south of the lake and thought that he might be able to maintain or gain some altitude to make it to the glider port. The pilot initiated a climb, however the engine subsequently lost power again. The pilot then initiated a forced landing to the lake. After touchdown, the pilot and passenger exited the airplane before it sank. Witnesses from different locations around the lake, reported seeing a low-flying airplane in the area. One witness reported that the airplane came over the hills at a low altitude and made a sweeping right turn toward the north. It then gained altitude, where the witness lost sight of it as it disappeared into a canyon. The witness stated that the engine sounded normal, but that the airplane was flying erratically. Another witness at a boat ramp saw the airplane traveling in a westerly direction about 40 ft above the water. He did not hear any unusual noises emanating from the engine. Finally, another witness, traveling in his jet boat reported that the airplane crashed about 20 ft in front him. The airplane was in a nose down attitude. According to the pilot, the engine was rebuilt about 2 years ago and had about 100-150 hours in service. The mixture was about one-half inch lean and the auxiliary pump was in the ON position as he was flying low. The airplane was recovered from the lake 23 days after the accident and transported to a storage facility. An examination of the airplane was performed by Federal Aviation Administration (FAA) inspectors. The engine cowling and right wing were not recovered from the lake. The propeller blades were bent aft. The crankshaft was manually rotated verifying accessory section continuity. The oil dipstick was removed, and several quarts of oil were observed. A visual inspection of the engine oil revealed no debris and it was free of metal shavings. The fuel feed lines at the wing roots were inspected and showed extensive wear to the outer lining; it was frayed, and the inner lining displayed dry rot. Fuel staining was present on the gascolator bowl. The amount of fuel on board was not determined due to water in the left-wing tank and the separation of the right wing.