page_title: Caio Duilio-class ironclad
section_title: Armament and armor
hierarchical_section_title: Caio Duilio-class ironclad / Design / Armament and armor
context_page_description: The Caio Duilio class was a pair of ironclad turret ships built for the Royal Italian Navy in the 1870s and 1880s. The two ships, Caio Duilio and Enrico Dandolo, were fitted with the largest guns available, 17.72 in rifled muzzle-loading guns, and were the largest, fastest and most powerful ships of their day. To save weight on such large vessels, the ship's designer, Benedetto Brin adopted a radical solution for the time: he reserved armor only for the central portion of the ship where it protected the ships' engines and ammunition magazines, while the rest of the hull were extensively sub-divided with watertight compartments.
  Both ships had uneventful careers. They spent the majority of their time in service with the Active and Reserve Squadrons of the main Italian fleet. There, they were primarily occupied with conducting training exercises. In 1895–1898, Enrico Dandolo was heavily reconstructed, but the excessive cost of the modernization prevented Caio Duilio from being similarly rebuilt. Both ships were reassigned as training ships in the early to mid-1900s.
context_section_description: Caio Duilio and Enrico Dandolo were armed with a main battery of four 17.7 in (450 mm) 100-ton guns of 20-caliber, mounted in two turrets placed en echelon amidships. These guns fired a 1,905-pound (864 kg) shell at a muzzle velocity of 1,490 to 1,670 feet per second (450 to 510 m/s) depending on the propellant charge. They had a rate of fire of one shot per fifteen minutes; the guns fired so slowly primarily as a result of their great size. As was customary for capital ships of the period, they carried three 14 in (360 mm) torpedo tubes. The torpedoes carried a 125 kg (276 lb) warhead and had a range of 600 m (2,000 ft).
  Throughout their careers, the ships' armament was revised significantly. In 1890, Caio Duilio received three 4.7 in (120 mm) 40-caliber guns; These guns fired a 36 lb (16 kg) shell at a velocity of 2,854 ft/s (870 m/s). In 1900, two 75 mm (3 in) guns, eight 57 mm (2.2 in) 40-caliber quick-firing guns, and four 37 mm (1.5 in) 20-caliber revolver cannon were also added. The 57 mm guns were manufactured by Nordenfelt and they fired a 6 lb (2.7 kg) shell. Enrico Dandolo was rebuilt in 1895–1898, and her armament was completely revised. In place of her 17.7 in guns she received four 10 in (250 mm) 40-caliber QF guns. These guns fired a 494.3 lb (224.2 kg) armor-piercing shell at a velocity of 2,460 ft/s (750 m/s). Her secondary battery consisted of five 4.7 in (120 mm) 40-caliber guns, sixteen 57 mm (2.2 in) 43-caliber QF guns—slightly longer versions of the same-caliber guns fitted to Caio Duilio—eight 37 mm (1.5 in) 20-caliber Hotchkiss revolver cannon, and four machine guns.
  The Caio Duilio-class ships were protected by steel belt armor that was 21.5 in (550 mm) thick at its strongest section, which protected the ship's magazines and machinery spaces. The belt armor plate was manufactured by the French steel mill Schneider-Creusot. The central citadel and the gun turrets received new nickel steel armor. Both ends of the belt were connected by transverse bulkheads that were 15.75 in (400 mm) thick. They had an armored deck that was 1.1 to 2 in (28 to 51 mm) thick. Their gun turrets were armored with 17 in of steel plate, while Enrico Dandolo's new turrets had only 8.8 in (220 mm) of steel plate. The ships' bow and stern were not armored, but they were extensively subdivided into a cellular "raft" that was intended to reduce the risk of flooding.
  The lack of armour on both ends of the design sparked controversy: after the former Chief Constructor of the Royal Navy Edward James Reed visited the ships under construction, he criticized this particular design feature, arguing that in case of damage to either end the entering water would have compromised the stability; the new Italian Minister of the Navy, Simone Pacoret di Saint-Bon, replied during a Parliament session that such an event was very unlikely, as it could happen only if all the bulkheads of the watertight compartments were destroyed.
caption: Caio Duilio's two main battery turrets
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