Duilio (often known as Caio Duilio) was an Italian that served in the Regia Marina during World War I and World War II. She was named after the Roman fleet commander Gaius Duilius. Duilio was laid down in February 1912, launched in April 1913, and completed in May 1916. She was initially armed with a main battery of thirteen guns, but a major reconstruction in the late 1930s replaced these with ten guns. Duilio saw no action during World War I owing to the inactivity of the Austro-Hungarian fleet during the conflict. She cruised the Mediterranean in the 1920s and was involved in the Corfu incident in 1923. During World War II, she participated in numerous patrols and sorties into the Mediterranean, both to escort Italian convoys to North Africa and in attempts to catch the British Mediterranean Fleet. In November 1940, the British launched an air raid on Taranto; Duilio was hit by one torpedo launched by a Fairey Swordfish torpedo bomber, which caused significant damage. Repairs lasted some five months, after which the ship returned to convoy escort duties. A fuel shortage immobilized the bulk of the Italian surface fleet in 1942, and Duilio remained out of service until the Italian surrender in September 1943. She was thereafter interned at Malta until 1944, when the Allies permitted her return to Italian waters. She survived the war, and continued to serve in the post-war Italian navy, primarily as a training ship. Duilio was placed in reserve for a final time in 1953; she remained in the Italian navy's inventory for another three years before she was stricken from the naval register in late 1956 and sold for scrapping the following year. Design Duilio was long overall and had a beam of and a draft of . At full combat load, she displaced up to . She had a crew of 35 officers and 1,198 enlisted men. She was powered by four Parsons steam turbines, with steam provided by eight oil-fired and twelve coal and oil burning Yarrow boilers. The boilers were trunked into two large funnels. The engines were rated at , which provided a top speed of . She had a cruising radius of at . The ship was armed with a main battery of thirteen 46-caliber guns in three triple turrets and two twin turrets. The secondary battery comprised sixteen 45-caliber guns, all mounted in casemates clustered