The Battleship Arms Races: My Gun is Bigger!
The launch of the HMS Dreadnought around 1900 began an epic race between the major world powers to see which navy could deploy the most battleships armed with the biggest guns. During this period there was a revolution in armament and protection that set Dreadnought apart from previous capital ship classes. No more would heavy guns be scattered around the ship, perhaps in barbettes arrayed in the hull above the waterline. Guns would now be 10" in diameter or greater, and be set in turrets containing two, three, or even four guns. These in turn would be placed approximately along the centerline of the battleship to ensure a stable and predictable firing platform.
This arrangement meant that a battleship's broadside could be more powerful than ever before, and that guns could fire at high angles to achieve ever steeper penetration angles more likely to break through a target's armor. It also began an era where the battleship firing broadside salvos of most or all its main armament at once would become the most vivid expression of naval might. And an arms race ensued as well, with continual innovations and one-upping the best designs of other navies.
Guns rapidly increased in diameter and length, and with these increases came boosts in the displacement of battleships, their length, and the amount of explosive power they could deliver onto a target at any given time. 10" guns gave way to 11", 12", and 13" guns. By the time of the First World War 14" and 15" guns were common and the battleships that mounted them were often called super-dreadnoughts. Many of the battleships and battlecruisers that tore into one another at Jutland in World War I carried such heavy guns, and development of even bigger guns did not cease during the Interwar period.
Indeed, by the Second World War 16" guns were becoming standard in the United States Navy, and updated 15" guns were installed on some of the biggest warships of the time, including the KMS Bismarck and KMS Tirpitz and the proposed Alsace Class battleship design put together in France. Of course the Japanese hold the record for the biggest naval guns deployed on a warship: their Yamato Class battleships were equipped with nine 18" guns - unheard of at the time.