Barrow's location and the availability of steel allowed the town to develop into a significant producer of naval vessels, a shift that was accelerated during World War I and the local yard's specialisation in submarines. The original iron- and steel-making enterprises closed down after World War II, leaving Vickers shipyard as Barrow's main industry and employer. Several Royal Navy flagships, the vast majority of its nuclear submarines as well as numerous other naval vessels, ocean liners and oil tankers have been manufactured at the facility.