The Vigilante, designed and built for the U.S. Navy by North American Aircraft Division at Columbus, Ohio, was the only Mach 2 bomber to serve aboard a Navy carrier. Initially designated the A3J-1 attack bomber, it was one of the largest and heaviest aircraft ever accepted for service aboard U.S. Navy carriers. Changing defense strategies marked a change of focus away from carrier-based, heavy attack squadrons. In 1964, all Vigilantes were reconfigured as reconnaissance aircraft and designated RA-5C. Reconnaissance gear was mounted in what had been the Vigilante's bomb bay. Other modifications allowed the RA-5C to carry four external fuel tanks. These additions increased the airplane's range on reconnaissance missions and allowed it to keep its attack capability with externally mounted bombs and rockets.