After the revolution one of the first major capital units which were introducted to the fleet were Konstruktor class, formely known as the Rimskoy Sodruzhestvo class. These large cruisers which were laid down during the WWI, were de facto the forrunners and inspiration to the washington heavy cruiser type ships build in foreing navies after the Washington Naval treaty. Altough the Konstruktor class featured 152mm main armament they were still regarded as heavy cruisers both in the Red Fleet and abroad due their overall size. A major reconstruction took place, as with many other older warships during the 30's where the ships gained new taller padoga-style tower, a catabult for aircraft and seccondaries in the form of 6 single 100mm AA guns.
(note, altough the design features some similarities to Enrr's Ansaldo cruiser projects, none of the parts are kitbashed)
Altough Komintern joined to the international naval treaties only after the London Naval conference in 1930, it already fielded a pure treaty cruiser design at the end of the 20's. Project 20 emerged from the need to awnser to new Japanese and British heavy cruisers. It featured three tripple 203mm guns in centerline arragment as well as 4 twin 100mm AA guns. Relatively large hangar was fitted amidship afbat the large funnel. Two ships were completed 1930 and 1931.
(all gredit for this design goes to Martin from warship projects forum, this is my tripute to his wonderfull AU design)
Altough signing the London naval treaty and therefore jurisdically tying to apply to the treaty limit of warships, Komintern introduced series of large cruisers in the 30's. The so called "project X" was one of the most peculiar and remarkable warshipdesigns ever fielded by any navy. The concept was actually a fusion of two paralel studies. The first one called large heavy cruiser outpowering the ever increasing size Japanese cruisers as well as to awnser to the new german "pocket battleships" and corresponding designs wich were to follow. To save the burden of trying to stretch the paramets of the naval treaties, Komitern decided simply just ignore them bluntly. The new cruiserdesign featured 4 tripple 240mm guns, an unusual calibre choise choosen to outrange the existing 203mm gun cruisers. Seccondaries were new 130mm twin mounts wich had in theory a dual purpose role. These were to be extremely fast and thus very long, 249m hull design was adopted. The seccond concept was an idea from a "flagship of the revolution". A sort of gunboat that would sail to where ever the proletarian uprising needed help. The concept called for large cruiser size vessel which was not only able to fight "borgerous" naval units but having significant shorebomparament capacity as well as a capacity to carry troops and their equipments. The long hull of the project X design allowed large hangar/storage for up to ten seaplanes. Aside those, two motor torbedoboats were carried as well as two minisubmarines.
All these plans came to live as pr. 25 Kraznyy Egipet class. Two units were completed 1936 and 1938. Third unit, Kraznyy Kintai completed in 1939 was slightly different, it featured larger hangar/storage for additional marine units and their equipments. The minisubmarines were dropped out. During the war, Kraznyy Sumatra had the catabult and seaplanes deleted and small landingcrafts to launch amphibian attacks to the Japanese occupied ilands in the pasific.
Altough pr. 25 was already biggest cruiserdesigns around, Komintern sougt even bigger design, close to the orginal Battlecruiser ideas. The develpment started with enlargening the pr. 25 but cutting down the non-tradditional cruiser roles. At first, 9 254mm guns were soughted but eventually 305mm guns were chosen. The seccondaries were also scaled up to 152mm but additional 100mm guns were added to give better AA cover. Three units of the pr. 69 were planned, two of them completed just before the Barbarosa, the third hull was finnished after the war into an aircraft carrier.