A uniform main battery did not mean that a dreadnought lacked smaller weapons. Both the Indefatigable and Lion types carried sixteen 4-inch secondary guns, while early dreadnoughts had anti-torpedo-boat armament from the outset. Larger secondary batteries became more useful as firing expensive main-battery rounds at cruisers made less sense. Dreadnought described the uniform main battery, leaving room for smaller guns suited to other targets.
Notable Point · 7:51-8:35
What dreadnought really meant for secondary guns
Dreadnoughts retained smaller guns against torpedo boats; a uniform main battery never meant that the ship carried only one gun type.