Bars-class submarines, or as they were officially called “Walrus-class submarines for the Baltic Sea,” were the most advanced modification of the so-called “Russian type” submarines, developed and built over a number of years under the leadership of I. G. Bubnova. These boats were designed in a rigid sequence. tality, namely: the previous type of boat (prototype) – the next type of boat, etc. This is most clearly seen in the types of submarines I.G. Bubnova: “Shark” - “Walrus” - “Leopard” - “Swan”. The characteristic design features of the “Russian boats” were: single-hull, lack of transverse waterproof bulkheads, ram formation of the bow end and powerful torpedo armament, most of which were open deck torpedo tubes devices of the Drzewiecki system.