 As built, the ships' main armament comprised thirteen 46-caliber 305-millimeter guns, designed by Armstrong Whitworth and Vickers, in five gun turrets.The turrets were all on the centerline, with a twin-gun turret superfiring over a triple-gun turret in fore and aft pairs, and a third triple turret amidships, designated 'A', 'B', 'Q', 'X', and 'Y' from front to rear.The turrets had an elevation capability of −5 to +20 degrees and the ships could carry 88 rounds for each gun.