Orion’s 13.5-inch guns reopened the calibre race

The Orion class was Britain’s first 13.5-inch-gunned capital-ship class. The change answered Germany’s arrival at parity with British 12-inch armament while the United States, Italy, and Japan were also advancing their heavy-gun programmes. British planners wanted to make the next jump before another navy did and force their rivals into a reactive design cycle. Germany then remained with 12-inch guns for much longer, while Britain proceeded to 15-inch weapons. The sequence shows that the dreadnought race involved technological timing as well as the number of hulls laid down.