At approximately 1305 Pacific time, a National Air & Space Museum Boeing S-307 ditched in the waters of Elliott Bay following a loss of engine power. The two pilots and two flight engineers were not injured. The flight had departed from Boeing Field approximately 1230 en route to Everett and landed without incident. The airplane took off again and the number three engine experienced a momentary surge, then normalized. Due to this anomaly, the flight crew decided to discontinue the flight activities and return to Boeing Field. The landing gear was lowered but the left main gear did not fully extend. The approach was aborted to orbit the area to try and remedy the situation. The flight engineer at the radio station managed to extend the left main and the flight then headed back to the airport. Then a low fuel pressure light was noted for the number three engine, followed by a loss of power. The flight crew feathered the engine but low fuel pressure was noted to the remaining three engines, which all subsequently began to lose power. The Captain reported that he did not believe that the aircraft could make it safely to BFI and opted to ditch the aircraft in Elliott Bay near the shoreline.