Gun caliber and turret layout were exercises in risk management. British firms and state facilities could develop 15-inch or 16.5-inch weapons, but a three-inch caliber jump carried more schedule risk when a European war might begin before the ships were ready. Choosing 15 inches also gave the United States room to answer with 16-inch guns instead of forcing an immediate leap to 18 inches. Britain could build triple turrets, while four twins preserved four independent mountings without turning the ship into a twelve-gun escalation. The resulting battery was powerful enough to defeat the German challenge while allowing the American twelve-gun 14-inch response to remain credible.
Notable Point · 1:19:07-1:32:14
Why 15-inch twins were the restrained choice
The armament discussion treats 15-inch twin turrets as a powerful but controlled leap that avoided a larger American response.