Origins

The distinctive all-big-gun armament of the dreadnought was developed in the first years of the 20th century as navies sought to increase the firepower and range of their battleships. The majority of pre-dreadnought battleships had a main armament of four heavy guns of 12-inch (305 mm) caliber, a secondary armament of six to eighteen quick-firing guns of 4.7 inches (119 mm) to 7.5 inches (191 mm) caliber, and other smaller weapons. Some designs had an intermediate battery of 8-inch (203 mm) guns. By 1903, serious proposals for an all-big-gun armament were circulated in several countries.[2]

All-big-gun designs commenced almost simultaneously in three navies. The Imperial Japanese Navy authorized the construction of Satsuma, designed with twelve 12-inch (305 mm) guns in 1904; she was laid down in May 1905.[3] The Royal Navy began the design of HMS Dreadnought in January 1905; she was laid down in October.[4] The U.S. Navy gained authorization for USS Michigan, carrying eight 12-inch guns in March;[4] she was laid down in December 1906.[5]

The move to all-big-gun designs was accomplished because a uniform, heavy-caliber armament offered advantages in both firepower and fire control. The newest 12-inch (305 mm) guns had more long-range firepower than a gun of 10-inch (254 mm) or 9.2-inch (234 mm) caliber.[6] Most historians also cite advantages in fire control; at long ranges guns were aimed by observing the splashes caused by shells fired in salvos, and it was difficult to interpret different splashes caused by different calibers of gun. There is still debate as to whether this point was important.[7]