Oktyabrskaya Revolutsiya in 1934, after her modernization.
Imperial Russian Battleship Gangut was laid up on 9 November 1918 for lack of manpower and was renamed Oktyabrskaya Revolutsiya (October Revolution) on 27 June 1925 while she was being refitted. She was recommissioned on 23 March 1926 and began a partial reconstruction on 12 October 1931, incorporating the lessons from the earlier modernizations of her sisters Marat and Parizhskaya Kommuna. The tubular tower-mast of Marat was replaced by a larger and sturdier structure with a KDP-6 fire control director, equipped with two 6-meter (20 ft) Zeiss rangefinders positioned on top. The aft superstructure was enlarged and a new structure was built just forward of it, with another KDP-6 director surmounting it, which required the repositioning of the mainmast 9 meters (30 ft) forward. This did not leave enough room for a derrick, as was used on Marat, so two large boat cranes were mounted on each side of the mainmast. Her funnel was curved to the rear rather than angled like Marat. Each turret received Italian 8-meter (26 ft) rangefinders and their roof armor was increased to 152-millimeter (6.0 in) in thickness. A new forecastle was fitted, much like that Marat’s, to improve seakeeping. Six 76.2-millimeter (3.00 in) 34-K anti-aircraft (AA) guns were added, three on the roofs of the fore and aft turrets. All twenty-five of her old boilers were replaced by a dozen oil-fired boilers originally intended for the Borodino-class battlecruiser Izmail. The space saved was used to add another inboard longitudinal watertight bulkhead that greatly improved her underwater protection. Her original Pollen Argo Clock mechanical fire-control computer was upgraded with a copy of a Vickers Ltd fire-control computer, designated AKUR by the Soviets, as well as a copy of a Sperry stable vertical gyroscope. These changes increased her displacement to 26,690 tonnes (26,270 long tons; 29,420 short tons) at full load and her overall length to 184.9 meters (607 ft). Her metacentric height decreased to 1.67 meters (5 ft 6 in) from her designed 1.76 meters (5 ft 9 in) as a result of her enlarged superstructures.
She finished her reconstruction on 4 August 1934. Her participation in the Winter War was limited to a bombardment of Finnish 10-inch (254 mm) coast defense guns on 18 December 1939 at Saarenpää in the Beryozovye Islands before the Gulf of Finland iced over. She failed to inflict any permanent damage before she was driven off by near misses. Oktyabrskaya Revolutsiya sailed to Tallinn shortly after the Soviets occupied Estonia, but she was refitted in February–March 1941 in Kronstadt and her anti-aircraft armament was reinforced. Two twin 76.2-mm 81-K mounts were mounted on her quarter deck. The magazines for these guns were probably situated in the rearmost casemates on each beam, which lost their 120-mm guns and twelve automatic 37-millimeter (1.5 in) 70-K guns were also added, three guns each on the middle turrets and the other six in the fore and aft superstructures. Four twin and four single 12.7-millimeter (0.50 in) DShK machine guns and two AA directors were also fitted. The large cranes were replaced by smaller ones taken from the ex-German heavy cruiser Petropavlovsk to make room for the anti-aircraft guns.
On 22 June 1941 Oktyabrskaya Revolutsiya was in Tallinn when the Germans invaded the Soviet Union, but she was forced to sail for Kronstadt by the advancing Germans. She opened fire on troop positions of the German 18th Army on 8 September from the channel between Leningrad and Kronstadt, and probably landed four 120-millimeter (4.7 in) guns on the following day for use ashore. She was badly damaged on 21 September by three bomb hits on her bow that knocked out two turrets and she was sent to the Ordzhonikidze Yard on 23 October for repairs. The Soviets took advantage of this time to add four more 37-mm 70-K AA guns and another twin 76.2-mm K-81 gun mount between February and April 1942. She was hit again by one heavy and three medium bombs dropped by Heinkel He 111s of KG 4 during the night of 4–5 April and again by three bombs on 24 April. Her repairs were completed in November 1942, although a quadruple 37-mm 46-K gun mount was added in September. She supported Soviet forces during the Siege of Leningrad, the Leningrad–Novgorod Offensive in January 1944 and the Vyborg–Petrozavodsk Offensive in June 1944. She received a Lend-Lease British Type 279 air-warning radar sometime during 1944. On 22 July 1944 she was awarded the Order of the Red Banner.
She was reclassified as a ‘school battleship’ on 24 July 1954 and stricken on 17 February 1956. She was slowly scrapped and her hulk still survived in May 1958.