How engines made armoured hulls practical

The transition to ironclads depended on more than the decision to add armour: engines had to move the extra weight, while guns and protection developed alongside them. France's La Gloire was an early armoured ship within a slow-moving arms race, rather than a simple one-nation breakthrough. British work on engines, armour, and guns allowed HMS Warrior to answer with a larger and faster design. British maritime dominance also shaped the pace, because few states were eager to provoke a direct challenge to the Royal Navy.