Designed by the French naval architect Camille Audenet as an iron-hulled version of the s, "Couronne" was also intended to fight in the line of battle, unlike the first British ironclads. The ship was classified as an armoured frigate because she only had a single gun deck and her traditional disposition of guns arrayed along the length of the hull also meant that she was a broadside ironclad. The ship was long, with a beam of . She had a maximum draft of , a depth of hold of and displaced . The ship's metacentric height of meant that she rolled less and was a better sea boat than the "Gloire"s. Her gun ports were slightly higher above the waterline than those of her predecessors, , and "Couronne" took aboard less water as well. She had a crew of 570 officers and enlisted men.