The Washington Naval Treaty prohibited capital-ship guns above 16 inches. A legal maximum quickly becomes a design target because governments do not want their new battleships armed below a rival's permitted limit. The same competitive logic made cruiser batteries cluster around the treaty's six- and eight-inch categories. A counterfactual with 18-inch-gunned versions of Agincourt and Hood shows how existing weapons could have shifted bargaining upward and accelerated the obsolescence of smaller-gunned ships. Treaty numbers therefore shaped architecture, fleet value, and diplomatic negotiation together.
Chapter · 30:13-32:55
Why treaty gun ceilings become design targets
Once the Washington treaty set a 16-inch ceiling, navies treated it as a design target because no government wanted its new battleships armed below the permitted maximum.