 Two turrets were mounted fore in a superfiring pair , while the other three were mounted aft of the main superstructure , all on the centerline . The placement of the rear gun turrets proved problematic . Capps placed the rear superfiring turret , Number 3 , closest amidships . Since it represented the greatest weight borne by the ship 's structure due to its tall barbette , this placement would allow it support by the greatest amount of underwater volume available . The other two rear turrets , Numbers 4 and 5 , were placed level and back to back . This arrangement was detrimental in two ways . First , Number 3 could not fire astern with Number 4 trained forward , which left only the two 12 " guns of Number 5 to do so . Second , because the engine room was situated between Numbers 3 and 4 , steam lines ran from the boiler rooms amidships around the ammunition magazine for Number 3 turret to the engine room . These lines , it was later found , had the potential to heat the powder in the magazine and degrade its ballistics . This design flaw was also prevalent in several British dreadnoughts but was considered inescapable by naval designers on structural grounds . 
