Why British planners considered 14-inch battleship guns

Why did British planners think 14-inch guns might be superior?

They offered a potential advantage in automation and rate of fire, while shaping the wider battleship-design competition.

Fourteen-inch shells are lighter and easier to move through a mounting than larger ammunition. That makes powered handling and automation more attainable and can support the high volume of fire favoured by Admiral Chatfield. A smaller weapon also permits lighter armour protection and potentially a lighter ship when the design is balanced against the same calibre. Britain retained a mature fourteen-inch industrial base while rival navies were concentrating on sixteen-inch weapons. Agreement on a fourteen-inch limit could therefore force competitors to restart design work while Britain used an existing gun. Mechanical handling, rate of fire, protection, and arms-control advantage all contributed to the calibre's appeal.