The W89 200 kiloton (0.2 MT) warhead armed both the tactical Sea Lance area effect anti-submarine weapon for use far out at sea and the strategic bomber launched SRAM II stand off missile designed for use in the Soviet Union's interior. The strategic attacks on Hiroshima and Nagasaki utilized weapons of between 10 and 20 kilotons, but that was because the "Little Boy" and "Fat Man" bombs were the most destructive and only nuclear weapons then available.
The W89 200 kiloton warhead was used in two distinct roles: as an area effect anti-submarine weapon for use at sea with the Sea Lance system, and as a stand-off missile for strategic bombers targeting the Soviet Union's interior. The Hiroshima and Nagasaki attacks employed nuclear weapons of varying yields, mainly due to the limited options available at the time.