On August 21, 2018, about 1830 Alaska daylight time, a Cessna 185 airplane, N8041R, sustained substantial damage when it was involved in an accident near Kaktovik, Alaska. The airline transport pilot was uninjured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that he was on a multi-leg trip to find a hunting camp along the remote Kangakut River. Before the flight, he filled the fuel tanks to capacity (84 gallons total /78 gallons usable.) Before the third leg of the trip, he checked the fuel tank levels with a dipstick, which indicated about 15 gallons in each tank. At the end of the third leg of the trip, while approaching a river gravel bar, the engine lost power and the pilot was forced to make a landing straight ahead. He advanced the throttle to full and confirmed that the mixture and propeller controls were in the full forward position. The propeller was windmilling. As he approached the landing surface, he activated the auxiliary fuel pump and engine power was restored; however, the airplane was too low to recover, and it impacted the brush-covered terrain. The main landing gear sheared off and the airplane slid off the riverbank, resulting in substantial damage to the fuselage, left elevator and right lift strut. The airplane was recovered and examined. The engine was intact and attached to the airframe. There was no damage to the engine, lines or accessories observed. The propeller rotated smoothly when turned by hand. Fuel was present in the fuel filter bowl and line to the engine. The wings were removed during the recovery; the recovery crew noted very little fuel in one tank and none in the other. The pilot stated that he observed a fuel leak from the left wing fuel vent at the accident scene and provided photographic evidence. After replacing the damaged propeller and supplying fuel to the engine, a test run of the engine revealed no anomalies. The pilot provided GPS data from the flight, which indicated that the airplane flew for a total of 4.5 hours before the accident. The Cessna 185 pilot operating handbook indicated a fuel consumption rate between 11.1 gallons and 14.2 gallons per hour for cruise conditions at 2,500 ft mean sea level, between 2,200 and 2,400 rpm and 22 and 24 inches manifold pressure. The GPS data indicated that the loss of power occurred after the pilot completed two tight turns over the intended landing area. The last turn was to the left at a rate of 6.4° per second, over twice that of a standard-rate turn.