A J3 Hood, dual-purpose secondaries, and higher treaty limits

If the intended Hood replacement is J3, what happens to the class and its six-inch secondary battery?

Four J3s are still expected, with an interwar change to twin 5.25-inch dual-purpose mounts and pressure for a higher treaty displacement limit.

The intended design is clarified as J3 with 15-inch guns, rather than the larger 18-inch-gun K3. Its post-Jutland features are the reason given for completing all four ships without the historical Admiral-class redesign difficulties. Six-inch secondaries would probably be replaced during the interwar years by twin 5.25-inch dual-purpose mounts, possibly five mounts per side. Four ships at roughly 45,000 tons would make that figure a possible treaty baseline because Britain would retain them. A further L3 battleship programme with nine 18-inch guns would increase the imbalance. In that expanded scenario, an American or Japanese building holiday is treated as unacceptable because it would leave Britain with the most powerful completed ships.