The saying "the best defense is a good offense" is well known, but not indisputable. If it was true, there would be no fortresses. People weathered sieges and assaults behind their walls for thousands of years. When the 20th century came and brought internal combustion engines with it, some people thought "why not bring a fortress into motion?"
Guards Major Derkach (initials unknown) was a pilot in the 7th Guards Rzhev Fighter Air Division or the 2nd Fighter Air Corps, but he decided to design a land-based giant with colossal firepower. Its design was sent to ABTU in the fall of 1943.
First, Derkach described the properties of his "moving fortress". He started with:
"Due to its large internal volume, it can fit powerful armament inside, equal to one artillery and one infantry regiment, or, taking its invincibility into account, the power of one infantry division."
The inventor armed his creation with 16 medium caliber guns and 35-40 machineguns, as well as "active offensive chemical weapons". The moving fortress was designed to break through enemy defensive lines. Enemy fire would be unable to harm this all-crushing monstrosity.
"Due to its shape, it is impervious to all types of weapons, except maybe a direct hit from a heavy shell... aside from the tracks that can be destroyed with a powerful explosive."
The moving fortress could be a reliable weapon for delivering soldiers behind enemy lines and crushing his supply lines. Derkach lauded its absolute terrain passability: "its sharp nose will uproot all trees (aside from century-old ones) and bend them around the hull". And, finally, "will have a crushing effect on enemy morale, as no human spirit can stand before such a monster."
Derkach's design reached 600 tons in weight. The surface area of the main tracks was 100 square meters. Additionally, the front and rear parts of the fortress would have extra tracks that helped it travel over soft terrain and ditches. "Additional tracks can be activated to loosen and flatten any slope or dirt wall."
The vehicle was crewed by 105 men, which isn't exceptional, considering the number of guns planned. Even in the most vulnerable parts of the hull, the crew would be protected by triple-layered armour at least 220 mm thick. The inner part of the hull was a "whole metallic egg-like shape". The second layer, made of rubber, would be right up against the inner layer. The surface of the moving fortress would be composed of "independent convex scales that would overlap each other, like the scales of a fish". That's not all. Derkach planned to add 10-12 volute springs between each scale and the hull to soften the blow when a shell hit.
Four diesel engines would bring the monster to life. Derkach wanted to use crude oil, theorizing that this would make accidental fires almost impossible.
In the end, the inventor honestly admits that he does not have the necessary knowledge to fully flesh out his design. He was already proud enough of his idea and sketches of the "moving fortress".
Engineers from the inventions department examined Derkach's proposal. Their reply, a secret, like all materials on the topic, was as brief as the inventor's list of features.
First, Engineer-Colonel Frolov wrote, such a design would result in colossal manufacturing difficulty, and would come at a great material cost. During the Great Patriotic War, this was enough to put an end even to a much more reasonable design. Second, it would not be possible to transport this moving fortress by rail. It would not be able to move across bridges. Water hazards would be impassable for Derkach's design.
The armour that was so hyped up by the inventor became worthless due to the tank's suspension. If such a superheavy tank was immobilized, it would be impossible to recover from the battlefield, and would not be easy to fix in the field. The immobilized tank would be an easy target for enemy artillery and bombs. "Tactically speaking, the use of such types of tank will have no effect in combat. Due to aforementioned reasons, the proposal is declined", specialists wrote.
To be fair, Guards Major Derkach was not alone with his enthusiasm and imagination. The German 1000 ton Ratte project is well known. It duplicated many of the drawbacks of the "moving fortress". Such ideas came up in the USSR both before and after, but the ideal method of attack and defense during the war, a traditional tank, did not change.
Original article available here.