Conte di Cavour - class battleship The " Conte di Cavour " - class battleships were a group of three dreadnought s built for the Royal Italian Navy ( " Regia Marina " ) in the 1910s . The ships were completed during World War I , but none saw action before the end of hostilities . was sunk by a magazine explosion in 1916 and sold for scrap in 1923 . The two surviving ships , and , supported operations during the Corfu Incident in 1923 . They were extensively reconstructed between 1933 and 1937 with more powerful guns , additional armor and considerably more speed than before . Both ships participated in the Battle of Calabria in July 1940 , when " Giulio Cesare " was lightly damaged . They were both present when British torpedo bombers attacked the fleet at Taranto in November 1940 , and " Conte di Cavour " was torpedoed . She was grounded with most of her hull underwater and her repairs were not completed before the Italian surrender in September 1943 . " Conte di Cavour " was scrapped in 1946 . " Giulio Cesare " escorted several convoys , and participated in the Battle of Cape Spartivento in late 1940 and the First Battle of Sirte in late 1941 . She was designated as a training ship in early 1942 , and escaped to Malta after Italy surrendered . The ship was transferred to the Soviet Union in 1949 and renamed " Novorossiysk " . The Soviets also used her for training until she was sunk when a mine exploded in 1955 . She was scrapped in 1957 . Design and description . The " Conte di Cavour " - class ships were designed by Rear Admiral Engineer Edoardo Masdea , Chief Constructor of the " Regia Marina " , and were ordered in response to French plans to build the s . They were intended to be superior to the " Courbet " s and to remedy ' s perceived flaws of weak protection and armament . As upgrading a warship ' s protection and armament on a similar displacement typically requires a loss in speed , the ships were not designed to reach the of their predecessor . They were still given a advantage over the standard of most foreign dreadnoughts . Foreign dreadnoughts were being designed with guns , but the " Regia Marina " was forced to use guns in the " Conte di Cavour " s because Italy lacked the ability to build larger guns . An additional gun , making a total of 13 , was added to offset this deficiency . Taking advantage of the lengthy building times of these ships , other countries were able to build dreadnoughts that were superior in protection and armament , with the exception of the French . Construction was delayed by late deliveries of the 305 - millimeter guns and armor plates as well as shortages of labor . The Italo - Turkish War of 1911 – 1912 diverted workers at the shipyards for repairs and maintenance of the ships participating in the war . The Italians imported the raw nickel steel for their armor from America and Britain and processed it into their equivalent of Krupp cemented armor , called Terni cemented , but there were problems with this process and suitable plates took longer to produce than planned . Basic characteristics . The ships of the " Conte di Cavour " class were long at the waterline , and overall . They had a beam of , and a draft of . They displaced at normal load , and at deep load . The " Conti de Cavour " class was provided with a complete double bottom and their hulls were subdivided by 23 longitudinal and transverse bulkheads . The ships had two rudders , both on the centerline . They had a crew of 31 officers and 969 enlisted men . Propulsion . The original machinery for all three ships consisted of three Parsons steam turbine sets , arranged in three engine rooms . The center engine room housed one set of turbines that drove the two inner propeller shafts . It was flanked by compartments on either side , each housing one turbine set which powered the outer shafts . Steam for the turbines was provided by 20 Blechynden water - tube boilers in " Conte di Cavour " and " Leonardo da Vinci " , eight of which burned oil and twelve of which burned both oil and coal . " Giulio Cesare " used a dozen each oil - fired and mixed - firing Babcock & Wilcox boilers . Designed to reach a maximum speed of , none of the ships reached this goal on their sea trials , despite generally exceeding the rated power of their turbines . They only achieved speeds ranging from using . The ships could store a maximum of of coal and of fuel oil that gave them a range of at , and at . Each ship was equipped with three turbo generator s that provided a total of 150 kilowatts at 110 volts . Armament . As built , the ships ' main armament comprised thirteen 46 - caliber 305 - millimeter guns , designed by Armstrong Whitworth and Vickers , in five gun turrets . The turrets were all on the centerline , with a twin - gun turret superfiring over a triple - gun turret in fore and aft pairs , and a third triple turret amidships , designated ' A ' , ' B ' , ' Q ' , ' X ' , and ' Y ' from front to rear . This was one less gun than the Brazilian , then the most heavily armed battleship in the world ; " Rio de Janeiro " s guns were mounted in seven twin - gun turrets . The turrets had an elevation capability of −5° to + 20 degrees and the ships could carry 100 rounds for each gun , although 70 was the normal load . Sources disagree regarding these guns ' performance , but naval historian Giorgio Giorgerini claims that they fired armor - piercing ( AP ) projectiles at the rate of one round per minute and that they had a muzzle velocity of which gave a maximum range of . The turrets had hydraulic training and elevation , with an auxiliary electric system . The secondary armament on the first two ships consisted of eighteen 50 - caliber guns , also designed by Armstrong Whitworth and Vickers , mounted in casemate s on the sides of the hull . These guns could depress to −10 degrees and had a maximum elevation of + 15 degrees ; they had a rate of fire of six shots per minute . They could fire a high - explosive projectile with a muzzle velocity of to a maximum distance of . The ships carried a total of 3 , 600 rounds for them . For defense against torpedo boat s , the ships carried fourteen 50 - caliber guns ; thirteen of these could be mounted on the turret tops , but they could be mounted in 30 different positions , including some on the forecastle and upper decks . These guns had the same range of elevation as the secondary guns , and their rate of fire was higher at 10 rounds per minute . They fired a AP projectile with a muzzle velocity of to a maximum distance of . The ships were also fitted with three submerged torpedo tube s , one on each broadside and the third in the stern . Armor . The " Conte di Cavour " - class ships had a complete waterline armor belt that was high ; of this was below the waterline and above . It had a maximum thickness of amidships , reducing to towards the stern and towards the bow . The lower edge of this belt was a uniform in thickness . Above the main belt was a strake of armor thick that extended up to the lower edge of the main deck . Above this strake was a thinner one , 130 millimeters thick , that extended from the bow to ' X ' turret . The upper strake of armor protected the casemates and was thick . The ships had two armored decks : the main deck was thick in two layers on the flat that increased to on the slopes that connected it to the main belt . The second deck was thick , also in two layers . Fore and aft transverse bulkheads connected the armored belt to the decks . The frontal armor of the gun turrets was in thickness with thick sides , and an roof and rear . Their barbette s also had 230 - millimeter armor above the forecastle deck that reduced to between the forecastle and upper decks and 130 millimeters below the upper deck . The forward conning tower had walls 280 millimeters thick ; those of the aft conning tower were 180 millimeters thick . The total weight of the protective armor was , just over 25 per cent of the ships ' designed displacement . The total weight of the entire protective system was , 30 . 2 per cent of their intended displacement . Modifications and reconstruction . Shortly after the end of World War I , the number of 50 - caliber 76 mm guns was reduced to 13 , all mounted on the turret tops , and six new 40 - caliber 76 - millimeter guns were installed abreast the aft funnel . In addition two license - built 2 - pounder anti - aircraft ( AA ) guns were mounted on the forecastle deck abreast ' B ' turret . In 1925 – 26 the foremast was replaced by a tetrapodal mast , which was moved forward of the funnels , the rangefinder s were upgraded , and the ships were equipped to handle a Macchi M . 18 seaplane mounted on the center turret . Around that same time , one or both of the ships was equipped with a fixed aircraft catapult on the port side of the forecastle . The sisters began an extensive reconstruction program directed by Vice Admiral ( " Generale del Genio navale " ) Francesco Rotundi in October 1933 . This lasted until June 1937 for " Conte di Cavour " and October 1937 for " Giulio Cesare " , and resulted in several changes . A new bow section was grafted over the existing bow which increased their length by to and their beam increased to . Their draft at deep load increased to for " Conte di Cavour " and for " Giulio Cesare " . All of the changes made during their reconstruction increased their displacement to at standard load and at deep load . The ships ' crews increased to 1 , 260 officers and enlisted men . Only 40 % of the original ship ' s structure remained after the reconstruction was completed . Two of the propeller shafts were removed and the existing turbines were replaced by two Belluzzo geared steam turbines rated at . The boilers were replaced by eight superheated Yarrow boilers with a working pressure of . On her sea trials in December 1936 , before her reconstruction was fully completed , " Giulio Cesare " reached a speed of from . In service their maximum speed was about . The ships now carried of fuel oil which provided them with a range of at a speed of . The center turret and the torpedo tubes were removed and all of the existing secondary armament and AA guns were replaced by a dozen 120 mm guns in six twin - gun turrets and eight AA guns in twin turrets . In addition the ships were fitted with a dozen 54 - caliber Breda light AA guns in six twin - gun mounts and twelve Breda M31 anti - aircraft machine gun s , also in twin mounts . The guns were bored out to and their turrets were modified to use electric power , a fixed loading angle of + 12 degrees , and the guns could now elevate to + 27 degrees . The 320 mm AP shells weighed and had a maximum range of with a muzzle velocity of . In 1940 the 13 . 2 mm machine guns were replaced by 65 - caliber AA guns in twin mounts . " Giulio Cesare " received two more twin mounts as well as four additional 37 mm guns in twin mounts on the forecastle between the two turrets in 1941 . The tetrapodal mast was replaced with a new forward conning tower , protected with thick armor . Atop the conning tower there was a director fitted with two large stereo - rangefinders , with a base length of . The deck armor was increased during reconstruction to a total of over the engine and boiler rooms and over the magazines , although its distribution over three decks , each with multiple layers , meant that it was considerably less effective than a single plate of the same thickness . The armor protecting the barbettes was reinforced with plates . All this armor weighed a total of . The existing underwater protection was replaced by the Pugliese system that consisted of a large cylinder surrounded by fuel oil or water that was intended to absorb the blast of a torpedo warhead . It lacked enough depth to be fully effective against contemporary torpedoes . A major problem of the reconstruction was that the ships ' increased draft meant that their waterline armor belt was almost completely submerged with any significant load . Service . " Conte di Cavour " and " Giulio Cesare " served as flagship s in the southern Adriatic Sea during World War I , but saw no action and spent little time at sea . " Leonardo da Vinci " was also little used and was sunk by an internal magazine explosion at Taranto harbor on the night of 2 / 3 August 1916 while loading ammunition . Casualties included 21 officers and 227 enlisted men killed . The Italians blamed Austro - Hungarian saboteur s , but unstable propellant may well have been responsible . The ship was refloated , upside down , on 17 September 1919 and righted on 24 January 1921 . The " Regia Marina " planned to modernize her by replacing her center turret with six AA guns , but lacked the funds to do so and sold her for scrap on 22 March 1923 . In 1919 , " Conte di Cavour " sailed to North America and visited ports in the United States as well as Halifax , Canada . " Giulio Cesare " made port visits in the Levant in 1919 and 1920 . " Conte di Cavour " was mostly inactive in 1921 because of personnel shortages and was refitted at La Spezia from November to March 1922 . Both battleships supported Italian operations on Corfu in 1923 after an Italian general and his staff were murdered on Corfu ; Benito Mussolini was not satisfied with the Greek Government ' s response so he ordered Italian troops to occupy the island . " Conte di Cavour " bombarded the town with her 76 mm guns , killing 20 and wounding 32 civilians . " Conte di Cavour " escorted King Victor Emmanuel III and his wife aboard " Dante Aligheri " , on a state visit to Spain in 1924 and was placed in reserve upon her return until 1926 , when she conveyed Mussolini on a voyage to Libya . The ship was again placed in reserve from 1927 until 1933 . Her sister became a gunnery training ship in 1928 , after having been in reserve since 1926 . " Conte di Cavour " was reconstructed at the CRDA Trieste Yard while " Giulio Cesare " was rebuilt at Cantieri del Tirreno , Genoa between 1933 and 1937 . Both ships participated in a naval review by Adolf Hitler in the Bay of Naples in May 1938 and covered the invasion of Albania in May 1939 . Early in World War II , the sisters took part in the Battle of Calabria ( also known as the Battle of Punto Stilo ) on 9 July 1940 , as part of the 1st Battle Squadron , commanded by Admiral Inigo Campioni , during which they engaged major elements of the British Mediterranean Fleet . The British were escorting a convoy from Malta to Alexandria , while the Italians had finished escorting another from Naples to Benghazi , Libya . Admiral Andrew Cunningham , commander of the Mediterranean Fleet , attempted to interpose his ships between the Italians and their base at Taranto . Crew on the fleets spotted each other in the middle of the afternoon and the Italian battleships opened fire at 15 : 53 at a range of nearly . The two leading British battleships , and , replied a minute later . Three minutes after she opened fire , shells from " Giulio Cesare " began to straddle " Warspite " which made a small turn and increased speed , to throw off the Italian ship ' s aim , at 16 : 00 . At that same time , a shell from " Warspite " struck " Giulio Cesare " at a distance of about . The shell pierced the rear funnel and detonated inside it , blowing out a hole nearly across . Fragments started several fires and their smoke was drawn into the boiler rooms , forcing four boilers off - line as their operators could not breathe . This reduced the ship ' s speed to . Uncertain how severe the damage was , Campioni ordered his battleships to turn away in the face of superior British numbers and they successfully disengaged . Repairs to " Giulio Cesare " were completed by the end of August and both ships unsuccessfully attempted to intercept British convoys to Malta in August and September . On the night of 11 November 1940 , " Conte di Cavour " and " Giulio Cesare " were at anchor in Taranto harbor when they were attacked by 21 Fairey Swordfish torpedo bomber s from the British aircraft carrier , along with several other warships . One torpedo exploded underneath ' B ' turret at 23 : 15 , and her captain requested tugboats to help ground the ship on a nearby sandbank . His admiral vetoed the request until it was too late and " Conte di Cavour " had to use a deeper , , sandbank at 04 : 30 on 12 November . In an effort to lighten the ship , her guns and parts of her superstructure were removed and " Conte di Cavour " was refloated on 9 July 1941 . Temporary repairs to enable the ship to reach Trieste for permanent repairs took until 22 December . Her guns were operable by September 1942 , but replacing her entire electrical system took longer and she was still under repair when Italy surrendered a year later . The " Regia Marina " made plans to replace her secondary and anti - aircraft weapons with a dozen dual - purpose gun s in twin mounts , twelve 64 - caliber , and twenty - three 65 - caliber 20 mm AA guns . Her hulk was damaged in an air raid and capsized on 23 February 1945 . Refloated shortly after the end of the war , " Conte di Cavour " was scrapped in 1946 . " Giulio Cesare " participated in the Battle of Cape Spartivento on 27 November 1940 , but never got close enough to any British ships to fire at them . The ship was damaged in January 1941 by a near miss during an air raid on Naples ; repairs were completed in early February . She participated in the First Battle of Sirte on 17 December 1941 , providing distant cover for a convoy bound for Libya , again never firing her main armament . In early 1942 , " Giulio Cesare " was reduced to a training ship at Taranto and later Pola . She steamed to Malta in early September 1943 after the Italian surrender . The unsuccessfully attacked the ship in the Gulf of Taranto in early March 1944 . After the war , " Giulio Cesare " was allocated to the Soviet Union as war reparations in 1949 , and renamed " Novorossiysk " , after the Soviet city on the Black Sea . The Soviets used her as a training ship when she was not undergoing one of her eight refits in their hands . In 1953 , all remaining Italian light AA guns were replaced by eighteen 37 mm 70 - K AA guns in six twin mounts and six singles . They also replaced her fire - control systems and added radar s , although the exact changes are unknown . The Soviets intended to rearm her with their own 305 mm guns , but this was forestalled by her loss . While at anchor in Sevastopol on the night of 28 / 29 October 1955 , she detonated a large German mine left over from World War II . The explosion blew a hole completely through the ship , making a hole in the forecastle forward of ' A ' turret . The flooding could not be controlled and she later capsized with the loss of 608 men . " Novorossiysk " was stricken from the Navy List on 24 February 1956 , salvaged on 4 May 1957 , and subsequently scrapped .