With the withdrawal of the Mk.15 thermonuclear bombs in 1965, the US Navy only had the B-43 bombs as 1Mt high-yield strategic bombs. This was a consequence of J. Kennedy’s new policy of enhancing the arsenal of intercontinental ballistic missiles rather than the tactical nuclear weapons of the US Navy.With the cancellation of the Regulus II cruise missile, the Mk.27 bombs were only used by the A-3 Skywarrior and A-5 Vigilante aircraft that had a weapon with overwhelming power for a short period of time. The bomb weighed 1,425kg and was 3.60 meters long and 76cm in diameter and was the second “megaton type” thermonuclear bomb of the US Navy after Mk.15. Both were designed to attack cities or high-value military targets. They were equipped with fuzes that allowed air or ground burst.