March 8 and 9, 1862 the Federal and Confederate Navies clashed in the first battle of ironclad vessels, the USS Monitor and the CSS Virginia (The Battle of Hampton Roads). While the battle was indecisive, navies around the world paid heed and stopped building wooden hulled ships in favor of ironclad vessels. The USA and CSA went on to have more ironclad battles with ironclad vessels, the last being the Battle of the Great Mississippi where the CSS Stonewall and USS Montauk faced off resulting in a Confederate withdrawal.
In North America the British, French (Empire of Mexico), United States, Confederate States, and Texas are in a navel technology race. Steam-powered ironclad combat vessels are the standard for all nations of the world with variations being turrets, rams, muzzle or breech-loading cannon, and armor thickness.
Historical Note - History books really only talk about the Battle of Hampton Roads, but there were several battles between ironclads with victories on both sides. (See Battle of Mobile Bay and First Battle of Charleston Harbor)