On 10 February 1906, HMS Dreadnought, the world’s first modern battleship, was launched. The Dreadnought was a revolution in military affairs so rarely seen in history. The moment the Dreadnought slid into Portsmouth Harbor, every fighting ship in the world was immediately obsolete. Upon learning of it, US President Theodore Roosevelt sent America’s battle fleet, “The Great White Fleet” (because it was painted white, you bigot) to circumnavigate the world ostensibly to show America’s global commitment. But in reality because America’s pre-dreadnought battleships were no better than scrap metal in an actual fight, and only useful for showing the flag against colonies and nations whose resident professional naval personnel were ignorant of the new paradigm in naval warfare. It’s telling that the Great White Fleet only made one stop in Europe, Gibraltar.
At the turn of the century, naval battles were characterized by slow battleships initially firing at long range by a small amount of big guns in order to damage the enemy enough to put him out of position. Then the object was to close the range so many more smaller guns with higher rates of fires could do the killing damage. Advances in metallurgy meant the smaller guns had to get closer to penetrate. And the larger guns’ splashes couldn’t be identified among smaller guns’ splashes making correction difficult and marginalizing the bigger guns at close ranges. In any case, the widespread use of the torpedo in destroyers and cruisers kept distances long (in order give the ships time to avoid them). By the Russo-Japanese War, long distance gunnery reigned supreme and the first combatant to gain position usually won (as seen clearly in the Battle of Tsuchima).
The HMS Dreadnought was the first ship built specifically to these new realities. She had a uniform battery of ten 12” guns in five turrets and forewent the medium range 6” and 8” guns of her predecessors. She was the first ship with steam turbines which nearly doubled her speed. She had the latest fire control, and her armor was impenetrable to all but the largest guns and torpedoes of the day. (Shit quality steel was used in passenger liners… like the Titanic.)
The HMS Dreadnought was as fast as a cruiser, had as many torpedoes as a small destroyer squadron, had the long range fire power of five pre-dreadnought battleships, and the armor of Cthulhu. She set off a naval arms race across the world that wouldn’t slow down until after the First World War.