The ships' main armor deck was thick in the central citadal, and the sides of the deck sloped downward to connect to the bottom edge of the belt. The sloped portion increased in thickness to , and the resulting compartment created was used as a coal bunker, which would provide additional protection for the ships' interiors when the bunkers were full. Compartments on either side of the torpedo bulkhead, which were set back about , were similarly used to store coal. In the bow and stern sections, the deck was thickened to ; it was increased further to over the steering compartment. The forecastle deck was over the secondary battery and 2 to 3 cm above the torpedo bulkhead.