The Douglas TBD-1 Devastator was designed as a torpedo bomber for the USN and entered service in 1937. The TBD Devastator marked a lot of firsts for the USN. It was the first widely-used carrier-based monoplane, first all metal USN aircraft, first completely enclosed cockpit that stretched almost half the length of the fuselage, first hydraulic folding wings. When bombing the bombardier would lie under the pilot seat and look through a window in the floor to do his sighting.