Why the secondary battery can decide the fight

An all-guns design creates a strong temptation to crowd the hull with six-inch weapons. In this scenario, rapid-firing medium guns do much of the practical damage, while the heavy battery supplies reach and prestige. The historical design logic described here expected the secondary battery to do much of the killing once targets entered its range. A warship's advertised main armament and its most productive weapon system could therefore be different batteries.