 Each ship carried eight BL 12 @-@ inch ( 305 mm ) Mk X guns in four BVIII * twin turrets . Two turrets were mounted fore and aft on the centreline , identified as ' A ' and ' X ' respectively . Two wing turrets were mounted amidships en echelon between the funnels , identified as ' P ' and ' Q ' . ' P ' turret was mounted on the port side and normally faced forward , ' Q ' turret was mounted on the starboard side and normally faced aft ( rearwards ) . ' P ' and ' Q ' turrets were staggered — ' P ' was forward of ' Q ' , enabling ' P ' to fire in a 70 ° arc to the starboard side and ' Q ' to likewise fire towards the port side . These were the same guns as those mounted in Dreadnought , the Lord Nelson class and Bellerophon class . 
