Book excerpt: The nineteenth century saw several major innovations in naval warfare. Reliable steam engines made it so that ships no longer depended on the wind and could maneuver more freely. At the same time, new explosive shells were developed, replacing cannonballs, and no wooden ship could withstand them. In response to these shells, a new class of self-propelled, armored "ironclads" was invented and quickly revolutionized naval warfare. A comprehensive look at the makeup of these "ironclad" warships. A technical view of the powerful weaponry that compelled these radical innovations. A look at the historic battles that proved the necessity of engines and armor. A discussion of the new tactics employed by nineteenth-century navies and the revival of an old classic -- the "ram."