French battleship Diderot Diderot was one of the six semi - dreadnought battleship s built for the French Navy in the early 1900s . Shortly after World War I began , the ship participated in the Battle of Antivari in the Adriatic Sea and helped to sink an Austro - Hungarian protected cruiser . She spent most of the rest of the war blockading the Straits of Otranto and the Dardanelles to prevent German , Austro - Hungarian and Turkish warships from breaking out into the Mediterranean . " Diderot " briefly participated in the occupation of Constantinople after the end of the war . She was modernized in 1922 – 25 and subsequently became a training ship . The ship was condemned in 1936 and later sold for scrap . Design and description . Although the s were a significant improvement from the preceding , they were outclassed by the advent of the dreadnought well before they were completed . This , combined with other poor traits , including the great weight in coal they had to carry , made them rather unsuccessful ships , though their numerous rapid - firing guns were of some use in the Mediterranean . " Diderot " was long overall and had a beam of and a full - load draft of . She displaced at deep load and had a crew of 681 officers and enlisted men . The ship was powered by four Parsons steam turbines using steam generated by twenty - six Belleville boiler s . The turbines were rated at and provided a top speed of around . " Diderot " , however , reached a top speed of on her sea trials . She carried a maximum of of coal which allowed her to steam for at a speed of . " Diderot " s main battery consisted of four 305mm / 45 Modèle 1906 gun s mounted in two twin gun turret s , one forward and one aft . The secondary battery consisted of twelve 240mm / 50 Modèle 1902 gun s in twin turrets , three on each side of the ship . A number of smaller guns were carried for defense against torpedo boat s . These included sixteen L / 65 guns and ten Hotchkiss gun s . The ship was also armed with two submerged torpedo tube s . The ship ' s waterline armor belt was thick and the main battery was protected by up to of armor . The conning tower also had 300 mm thick sides . Wartime modifications . During the war 75 mm anti - aircraft guns were installed on the roofs of the ship ' s two forward 240 mm gun turrets . During 1918 , the elevation of the 240 mm guns was increased which extended their range to . Career . Construction of " Diderot " began on 26 December 1906 by Ateliers et Chantiers de la Loire in Saint - Nazaire and the ship was laid down on 20 October 1907 . She was launched on 19 April 1909 and was completed on 1 August 1911 . The ship was assigned to the First Division of the First Squadron ( " escadre " ) of the Mediterranean Fleet when she was commissioned . The ship participated in combined fleet maneuvers between Provence and Tunisia in May – June 1913 and the subsequent naval review conducted by the President of France , Raymond Poincaré on 7 June 1913 . Afterwards , " Diderot " joined her squadron in its tour of the Eastern Mediterranean in October – December 1913 and participated in the grand fleet exercise in the Mediterranean in May 1914 . World War I . In early August 1914 , the ship cruised the Strait of Sicily in an attempt to prevent the German battlecruiser " Goeben " and the light cruiser " Breslau " from breaking out to the West . On 16 August 1914 the combined Anglo - French Fleet under Admiral Auguste Boué de Lapeyrère , including " Voltaire " , made a sweep of the Adriatic Sea . The Allied ships encountered the Austro - Hungarian cruiser , escorted by the destroyer , blockading the coast of Montenegro . There were too many ships for " Zenta " to escape , so she remained behind to allow " Ulan " to get away and was sunk by gunfire during the Battle of Antivari off the coast of Bar , Montenegro . " Voltaire " subsequently participated in a number of raids into the Adriatic later in the year and patrolled the Ionian Islands . From December 1914 through 1917 , the ship participated in the distant blockade of the Straits of Otranto while based in Corfu . In May 1918 , " Diderot " became flagship of the First Division of the Second Squadron and was transferred that month to Mudros with her sister ships , and , to prevent " Goeben " from breaking out into the Mediterranean and remained there until the end of the war . Postwar . After the Armistice of Mudros was signed on 30 October between the Allies and the Ottoman Empire , the ship participated in the early stage of the occupation of Constantinople from 12 November to 12 December . " Diderot " was based in Toulon throughout 1919 and was modernized in 1922 – 25 to improve her underwater protection . The ship became a training ship in 1927 and was condemned in 1936 . She was later sold for scrap and broken up in 1937 .