Do six-inch guns still have a place at sea?

Are six-inch naval guns still useful?

Yes for surface fire, and later automatic mounts could also serve in air defense, but older mountings such as Belfast's had limited anti-aircraft value.

HMS Belfast's six-inch battery remained primarily a surface weapon, with four-inch guns supplying the anti-aircraft layer. Later Tiger-class automatic mounts could employ the same caliber against aircraft. Elevation, loading arrangements, and fire control determine whether a nominally similar gun can perform that second role. The answer therefore separates the usefulness of a caliber from the capabilities of a particular mounting and fire-control system.