Many pre-dreadnoughts already carried 12-inch guns, so HMS Dreadnought's real leap lay in the number and role of those weapons. The all-big-gun layout turns the primary battery from a limited long-range tool into the ship's main means of destruction. Its three-inch weapons are focused on torpedo boats and destroyers rather than the enemy battle line. The same search for rapid decisive damage helps explain later pressure for nine 16-inch guns in the Nelson class and the continuing interest in still larger main-battery volume.
Notable Point · 53:35-57:34
Dreadnought moves killing power to the main battery
HMS Dreadnought concentrated enough 12-inch guns to make the main battery the ship's principal means of destruction.