 The primary armament of the "Number 13" class was eight 45-caliber 457-millimeter guns in four twin-gun turrets, two each superfiring fore and aft of the superstructure.No examples of this gun were ever built, but it was planned to fire a shell at a muzzle velocity of .The secondary battery consisted of 16 single 50-caliber guns was mounted in casemates in the superstructure.