The redesign uses secondary weapons against threats that the main battery is poorly suited to handle. Six-inch turrets fit the British expectation that battleships would need to counter torpedo-carrying attackers. Three-inch anti-aircraft weapons are then added as a common British fit of the period. The resulting arrangement connects secondary calibre and placement to doctrine, since protection against smaller attackers and aircraft belongs within the battleship's combat system.
Notable Point · 44:08-45:13
Six-inch secondaries and three-inch anti-aircraft guns
The revised British ship uses six-inch secondaries against torpedo threats and adds the three-inch anti-aircraft weapons common to the period.