Steam power frees designers from sailing constraints

Reliable steam power changed both displacement and layout. Sailing efficiency had forced designers to keep hulls light, while masts and rigging constrained guns, machinery, and hull shape. Stronger engines allowed heavier ships to force their way through the water with less dependence on wind. The Grumman Wildcat, Hellcat, and Avenger provide the aviation analogy: start with a powerful engine, then shape the vehicle around it. Vertical triple-expansion machinery could be arranged upward rather than across the hull, and multiple shafts reduced the consequences of one engine failing. Designers gained room for heavier armour, different gun arrangements, and new hull forms.