Argencourt's proposed secondary battery and refit

What secondary battery would the proposed Argencourt carry?

The initial concept uses five triple 4-inch mounts; a later refit could replace them with twin 5-inch mounts for a more efficient battery.

The initial arrangement uses five triple 4-inch mounts related to the secondary armament of Renown and Repulse, keeping the concept in its period. The layout gives nine 4-inch guns on a broadside, supplemented by a small anti-aircraft battery. Those triple mounts were awkward and manpower-intensive, which makes them a natural modernization target. A later refit could exchange them one-for-one for twin 5-inch or 5.25-inch weapons. That change keeps broadly similar weight while reducing crew demands and producing a more useful dual-purpose battery.