The ships had an upper deck that was 50 mm (2.0 in) thick, and an armored deck that was between 100–120 mm (3.9–4.7 in) thick amidships, and tapered down to 60 mm (2.4 in) at the bow and 80 mm (3.1 in) at the stern.[4] The deck was mounted low in the hull, however, which reduced the volume of internal space protected by the armored citadel. This contrasted with contemporary British and American designs that featured a single thick armored deck mounted high in the ship.[18]