Hero was — like her sister-ship — designed to be an improved version of Rupert with a ram as her main armament. It was assumed by the Board of Admiralty and within Naval Architecture circles that the supremacy of armour over artillery would allow such a ship to ram an enemy vessel without being seriously damaged by enemy gunfire. This assumption was never tested in action. By the time she was launched, ramming had been discarded, leaving her and her sister exposed as perhaps the two most useless turret-armed battleships ever built.