 Like the "Nassau" class which preceded it, the "Helgoland"-class ships carried their main armament in an unusual hexagonal configuration.Twelve 30.5 cm SK L/50 guns were emplaced in long-trunk Drh LC/1908 mountings, an improved version of the previous LC/1907 and LC/1906 mounts used in the "Nassau" class.The guns were arranged in pairs in six twin gun turrets, with one turret each fore and aft, and two on each flank of the ship.