Tirpitz's hesitation at increasing the armament of the new ships was lost when it became known in early 1907 that the United States Navy was building battleships with 30.5 cm guns. In March 1907, Tirpitz ordered the Construction Department to prepare a design with 30.5 cm guns and thick belt armor. Some dispute remained over the arrangement of the main battery. The two s being built for Brazil mounted the same number of guns, but in a more efficient arrangement. Superfiring turret pairs were placed on either end of the ship, with two wing turrets amidships. Tirpitz favored adopting this arrangement for the "Helgoland" class, but the Construction Department felt two superfiring turrets could be easily disabled by a single hit. As a result, the hexagonal arrangement of the preceding "Nassau"s was retained.