The question is why Britain did not keep 12-inch guns and spend the saved weight on armor. Italian and Russian ships carried twelve 12-inch guns, which made a ten-gun British twin-turret design look less decisive. The Royal Navy preferred twin turrets because they were cheaper and could be produced quickly, whereas matching twelve guns on the centerline would require six twin mountings and a more complicated ship. Increasing caliber preserved a powerful weight of fire without adopting that six-turret layout. The caliber increase raises the benchmark enough to identify Orion as the original super-dreadnought class. Queen Elizabeth follows later.
Notable Point · 7:50-9:12
Why Britain chose 13.5-inch guns for Orion
Britain increases gun caliber to offset twelve-gun Italian and Russian ships without adopting a complicated six-twin-turret centerline layout.