Dreadnought Era Battleship secondary armament

hms iron duke secondary armament in casemates alongside of ship

dreadnoughts characterized all-big-gun armament. broadly, era spans 1906, through super-dreadnought era, end of world war i.

during period, there variation in selection of secondary weapon. british practice, @ first, mount small guns (3-inch , 4-inch) considered tertiary battery. these guns mounted unarmoured in open, or later, in casemate battery. later, guns grew 6-inch size. in other navies, 6-inch size commonly mounted throughout era casemate battery.

british doctrine @ first held small guns anti-torpedo defense only. other navies, larger secondary battery, held should used against capital ships. instance, german doctrine, fighting in north sea, held poor visibility provided opportunity shorter ranges @ smaller guns effective. britain later came around point of view, although primary justification mounting 6-inch battery (in iron duke class) remained fighting against increasingly large torpedo boats , destroyers.

naval historians covering period disagree on value of secondary battery. arguing for, provided protection against surface torpedo craft without needing flotilla of supporting craft smoked range , burdened admiral additional command, control , signalling. arguing against, consumed considerable displacement (2000 tons or more), holes in side close waterline increased risk of capsizing, , not heavily armoured yet connected magazines threatened destruction of ship. there considerable difficulties in bringing secondary weapons action main guns; smoked range, splashed , obscured target, , might required maneuvers open secondary arcs put main guns @ disadvantage. battle experience showed capital ships accompanied flotillas, secondary batteries ineffective against capital ships, german battleship secondary batteries effective in jutland night action against british destroyers.