General-Admiral-class cruiser
The "General-Admiral"-class ships were a pair of armored cruisers built for the Imperial Russian Navy in the early 1870s. They are generally considered as the first true armored cruisers. Design and description. Originally classified as armored corvettes, the "General-Admiral"s were redesignated as semi-armored frigates on 24 March 1875. They were laid out as central battery ironclads with the armament concentrated amidships. The "General-Admiral"-class ships were long overall. They had a beam of and a draft of . The ships were designed to displace , but displaced as built, an increase of over . The iron -hulled ships were not fitted with a ram and their crew numbered approximately 482 officers and men. The ships had a vertical compound steam engine driving a single two-bladed, propeller, using steam provided by cylindrical boilers. The number of boilers differed between the sisters. "General-Admiral" had five that generated a working pressure of so that the engine produced . This gave her during a maximum speed around during her sea trials. "Gerzog Edinburgski" had four boilers and her engine made that propelled her at . The "General-Admiral" class carried a maximum of of coal which gave them an economical  range of at a speed of . They were ship-rigged with three masts. To reduce drag while under sail, the single funnel was retractable and the propeller could be hoisted into the hull. The sisters armament were four , two rifled breech-loading guns (RBL), and four early masnine-gun likes Engstrom guns. The ships had a complete waterline belt of wrought iron that ranged in thickness from 6 inches amidships to at the ends of the ships. The armor had a total height of , of which was below the waterline. The central battery was also protected by 6-inch armor  plates. Service. "General-Admiral" had was blown ashore during a heavy storm at Kronstadt in 1875, shortly after being completed. She did not participate in the Russo-Turkish War of 1877–78 and made one cruise in the Pacific in the early 1880s. The ship spent 1884–85 in the Mediterranean before beginning a refit in 1886 during which she was partially re-boilered. "General-Admiral" had her boilers replaced, her funnel was replaced by two non-retractable funnels, and a fixed propeller was installed in 1892. The ship was reclassified as a 1st-class cruiser on 13 February 1892 and participated  the Columibian Naval Review in Hampton Roads, Virginia, the following year. Afterwards she became a training ship. She became a school ship in 1906 and her armament was reduced accordingly. "Gerzog Edinburgski" was initially assigned to the Baltic Fleet, but made a lengthy Pacific cruise in 1881–84. She was refitted about 1890 in the same type as her sister's 1892 refit, although her engine and boilers were replaced in 1897. The ship became a training ship for petty officers and was formally reclassified as a school ship like her sister in 1906. The sisters were converted into minelayers in  1908–11 and renamed after lakes near Saint Petersburg, "General-Admiral" became "Narova" and "Gerzog Edinburgski" was renamed "Onega". Their rigging was reduced to pole masts, their armament was reduced to four guns, and they could carry 600–800 mines. They both participated in numerous minelaying missions in the early years of World War I, but "Onega" was hulked in 1915 as "Blokshiv No. 9" and became a mine storage ship in Helsinki. "Narova", however, continued to lay mines throughout the war. The Treaty of Brest-Litovsk required the Soviets to evacuate their base in March 1918 or have them interned by  newly independent Finland, even though the Gulf of Finland was still frozen over. The sisters were not included in the initial group of evacuated ships and were only permitted to leave in May for Kronstadt after lengthy negotiations with the Germans. Narova's crew joined the Soviets and she was used to mine the approaches to Petrograd later that year against the British forces operating in the Gulf of Finland against the Soviets. She was renamed "Dvadsatpyatavo Oktyabrya" (25 October) in 1922 The ultimate fates of the sisters are not exactly known. "Blokshiv No. 9" was apparently broken up in  the 1920s while "Dvadsatpyatavo Oktyabrya" became a mine storage hulk in 1938 before being sunk as a breakwater in the Neva River around 1959.