The problems first encountered during the war of the ironclads would now have to be dealt with aboard larger more powerful vessels with watertight compartments, problems such as how to move non-ambulatory casualties between decks, up ladders and through scuttles to sick bays and battle dressing stations.  Perhaps, more importantly, ventilating those spaces would become a major concern as more and more sailors lived and worked in compartments sandwiched between un-air conditioned multiple decks.