The hull's burned timbers were cut down past the vessel's original waterline, leaving just enough clearance to accommodate her large, twin-bladed screw propeller. A new fantail and armored casemate were built atop a new main deck, and a v-shaped breakwater (bulwark) was added to her bow, which attached to the armored casemate. This forward and aft main deck and fantail were designed to stay submerged and were covered in iron plate, built up in two layers. The casemate was built of of oak and pine in several layers, topped with two layers of iron plating oriented perpendicular to each other, and angled at 36 degrees from horizontal to deflect fired enemy shells.