Salfetkoruzhie is a portmanteau of Russian words “salfetka” (napkin) and “oruzhiye” (weapon), the equivalent of German “napkinwaffe”.
If you read a list of GABTU’s desires in 1940, you will encounter a mention of a 180 mm SPG on the SMK chassis. The tank proposal, and indeed, any 180 mm SPG was scratched out. Such a huge gun would be entirely impractical.
However, this is World of Tanks! Phrases like “impractical”, “overcomplicated”, “it would never happen”, and “oh god what are you doing” have no meaning here! Let’s grab a napkin and begin designing!
First, the most important part of the tank: the gun. In 1940, the only such gun in production was the B-1-P naval gun. The gun fired a 97.5 kg shell at 920 meters per second. Literature remains silent on its penetration abilities, but we can use math! Using deMarre’s equation, and the BL-10 as reference (that’s the closest weapon I have data for), I get a respectable 356 mm of penetration. Take that, gold ammo, we’re shooting through 2 Tigers back to back with credits now! The massive gun achieved a rate of fire of 6 round per minute on a ship, but in game, it would probably have to decrease to a more reasonable 2. As for alpha, a cool 1100 ought to do it, the same as the Object 261′s 180 mm gun. The gun weighs 19.6 tons, which would probably make it the heaviest gun in the game.
Now, for the hull. The SMK had KV-like armouring: 75 mm all around. The front turret weighs 3 tons, the big one (assuming it weighs as much as a KV turret) weighs 7. That’s 10 tons saved when removing the turrets, which is just half of the gun’s weight. The resulting tank would still be pretty heavy, even if all the casemate armour is achieved through removing hull armour. The SMK’s already mediocre maximum speed of 35 kph would be even lower. Such poor armour would make it very similar to the SU-100-Y: huge gun, terrible everything else. At, say, tier 8, the tank would be perfect. Its gun would be menacing, but its armour would be thin enough to be penetrated by any tank it will see.