The Delaware-class battleships of the United States Navy were the second class of American dreadnoughts; the class comprised two ships: and . With this class, the limit imposed on capital ships by the United States Congress was waived, which allowed designers at the Navy's Bureau of Construction and Repair to correct what they considered flaws in the preceding and produce ships not only more powerful but also more effective and rounded overall. Launched in 1909, these ships became the first in US naval history to exceed .
The Delawares carried a battery of ten guns in five turrets, an increase of two guns over the South Carolinas. With these ships, the US Navy re-adopted a full-fledged medium-caliber weapon for anti-torpedo boat defense. While the gun was smaller than that used by other major navies, this would, with few exceptions, become the standard medium-gun caliber for the US Navy for the better part of the 20th century. As for speed, the Delawares were capable of , a significant improvement over the earlier class's . This would become the speed for all American standard-type battleships. Propulsion systems were mixed; while North Dakota was fitted with steam turbines, Delaware retained triple-expansion engines. Direct-drive turbines were much less fuel-efficient, a significant concern for a Navy with Pacific responsibilities but lacking Britain's extensive network of coaling stations.
These ships saw varied service during their careers. During World War I, Delaware was part of Battleship Division Nine of the US Atlantic Fleet, and was assigned to the British Grand Fleet. She escorted convoys and participated in the blockade of the German High Seas Fleet. In contrast, North Dakota remained on the American coast throughout the war, due in part to worries about her troublesome turbine engines. Post-war, they conducted training cruises with the US Atlantic Fleet. In 1924, Delaware was broken up for scrap metal in accordance with the Washington Naval Treaty of 1922. North Dakota survived until 1931, when she too was scrapped, under the terms of the 1930 London Naval Treaty.
Design
Prompted by the launch of and misinformation about , the US Navy and Congress faced what they perceived as a vastly better battleship than the two battleships then under construction, which were designed under tonnage constraints that Congress had imposed on capital ships. Actually, the South Carolinas were inferior only in speed to Dreadnought; they carried fewer heavy guns but, unlike Dreadnought, could bring all of them to bear on the broadside. Because of this, they could fire an equal weight of metal. Also, because greater time and care had been taken with their armor and bulkhead arrangement, they were better protected than the British ship. None of this was realized at the time. Nevertheless, the Navy's Bureau of Construction and Repair (C&R) had struggled tremendously to design an adequate warship under congressional limits and had taken battleship design as far under those restrictions as it could. Seeing now that those limits had become unrealistic, Congress ended them; any subsequent constraints would be dictated by treaty limitations. The language of the authorizing act of June 26, 1906 was for a battleship "carrying as heavy armor and as a powerful armament as any known vessel of its class, to have the highest practicable speed and the greatest practicable radius of action."
The Delaware class was the second of 11 distinct US capital ship designs begun from 1906 to 1919; some 29 battleships and six battlecruisers were laid down during this period, though seven of the battleships and all six of the battlecruisers were cancelled. Except for the s, these were all relatively slow ships, designed for no more than . They ranged in displacement from . At this time, no US dreadnought class battleship had yet hit the water as all were either at some stage of building or in design. Virtually the entire US Navy battle line was being designed by drawing on experience from pre-dreadnought designs, or from observation of foreign battleship design.
The design for these ships was actually ready in 1905 or 1906. Two variants were offered—a 10-gun version on and a 12-gun alternative on . The larger ship was rejected as too expensive for the firepower it offered, even after its displacement was reduced to tons. Also, because C&R was required to consider private designs, construction on the Delawares did not commence until 1907. None of the private designs was considered remotely satisfactory by the Navy. However, Fore River later developed its version into the battleship , which was built for the Argentine navy. While the C&R design was considered superior, it still came under criticism, particularly for the poor placement of, and lack of protection for, the secondary armament.
General characteristics
The Delawares were significantly more powerful than their predecessors, the South Carolina-class, and are mentioned by Conway's All the World's Fighting Ships as the first to match the standard set by the British with Dreadnought. This was due in large part to the elimination of Congressional limits on the size of new battleships; the only restriction the Congress placed on their design was that the cost of hull and machinery could not exceed 6 million USD. The Delaware-class ships were also significantly larger than the South Carolinas. They were long at the waterline and long overall. By comparison, the South Carolina-class ships were long overall. The Delawares had a beam of and a draft of ; the South Carolinas measurements were and , respectively. The Delaware-class ships displaced at standard displacement and at full load, while the South Carolinas displaced at standard displacement and at full load. Their bows had an early example of bulbous forefeet.
Propulsion
For reasons including expected hostilities with Japan, requiring travel across the Pacific Ocean, long operational range was a recurrent theme in all US battleship designs. As an experiment, these ships received different powerplants. Delaware received triple-expansion reciprocating engines, while North Dakota was fitted with Curtiss direct drive steam turbine engines. Both ships had 14 Babcock & Wilcox boilers, both original power plants were rated at ; and both ships were capable of reaching 21 knots. Chief Constructor Washington L. Capps predicted North Dakota would have a 25 percent shorter radius than Delaware at 16 knots and 45 percent less at 14 knots, based on tank tests and the known performance of steam turbines at that time. This estimate was proved true during the ships' trial runs in 1909. Also, because Delawares engine bearings were equipped with forced lubrication instead of a gravity-fed system, she was able to steam at full speed for 24 hours without any need for engine repair. This would normally have been unthinkable as reciprocating engines were known generally to shake themselves apart if run at full power for long. However, this penchant for reliability came under question in the late 1930s as battleships with reciprocating engines performed poorly in the Pacific. By 1917, more powerful and efficient geared turbines had been installed in North Dakota to replace her Curtiss turbines. These provided horsepower, some greater than her original engines.