The first innovation was the use of steam power for propulsion.
This allowed ships to sail against winds and currents, though it consumed massive amounts of coal, which limited operational range to less than 10 days.
Therefore steam engines were often combined with traditional masts and sails.
The first steam-powered ships, driven by paddles, appeared in the 1830's CE.
A decade later the paddles were replaced by a screw propeller, which was far more efficient.
The French navy was the first to build steam-powered warships, introducing the Napoléon in 1850 CE.
This ship could achieve a speed of 22 kilometers per hour.
The second improvement was the introduction of the explosive shell in the 1840's CE by Henri-Joseph Paixhans.
With luck these shells could penetrate an enemy ship hull and strike an ammunition chamber, causing a massive explosion.
Early ironclads arrayed their guns on the broadsides, like ships-of-the-line had done for two centuries.
However soon guns were mounted on turrets and barbettes, to be able to fire in all directions.
The final piece of the puzzle was the use of iron hulls, replacing the millennia old wooden ones.
Initially wooden hulls were strengthened with iron plating.
The new material was water-tight, easier and quicker to produce and became steadily cheaper during the 19th century CE.
In battle its main advantage was that iron did not spray a rain of lethal wooden splinters when it was hit by enemy cannonballs.
The armor was steadily thickened, creating a kind of heavy floating gun platforms
that achieved speeds of only 7 kilometers per hour under their own power.
Too slow to fight wooden ships, they were nonetheless useful in pounding enemy shores.
The first fully iron-hulled ship was the British gunboat Nemesis, launched in 1839 CE, though wood-iron hybrids continued to be used for decades more.
In the 1850's CE all innovations were combined, making up true ironclads.
Navies struggled to find a balance between armor, firepower and speed.
The first battles between ironclads took place in the American Civil War, where they easily swept traditional wooden warships aside.
Sinking each other proved more difficult; cannonballs did little damage against the iron plating.
The armor of the new ships seemed so good that for about two decades the most popular offensive tactic was to ram enemy ships, instead of shooting at them.
That situation changed with the introduction of quick-firing guns.
These, combined with new armor-piercing ammunition, returned the advantage to the gunners and naval battles became gunfights once more.
Around the same time iron hulls were replaced by steel ones, though the ships were still called ironclads.
Ironclads dominated naval warfare for about half a century and were used into World War I.
But by then the dominant role had passed to the dreadnoughts.
War Matrix - Ironclad
Geopolitical Race 1830 CE - 1880 CE, Weapons and technology