There is a version that the idea of creating underground boats first appeared in the USSR. So, in the 30s of the XX century, engineers A. Treblev, A. Kirilov and A. Baskin created a real project of such an apparatus. According to their plan, this underground boat was to be used as a means of underground oil production. It was assumed that the apparatus would go deeper into the ground, determine the position of oil deposits, and lay an oil pipeline there. The construction of this underground boat is based on the structure of a mole. They say that this project was implemented, and the test of the device took place in the Urals under the Grace Mountain. Deepening into the rock was carried out using cutters similar to those used on coal miners. The device really destroyed hard rocks, slowly moving forward, however, unfortunately, it turned out to be unreliable. He often brokeand the project was deemed somewhat untimely.
But the development of underground boats in our country did not end there. So, at the beginning of 1940, Doctor of Technical Sciences, designer of underground roadheaders P. I. Strakhov was summoned by the future People's Commissar of Armaments of the USSR D. F. Ustinov. At that moment, Strakhov was involved in the construction of the Moscow metro. However, Ustinov invited him to take up another job. He asked Strakhov if he knew about the work of the engineer Treblev, who proposed the design of an autonomous underground boat in the 30s. Strakhov answered this question in the affirmative, after which Ustinov said that for him there was a task much more important than the metro - the development of an underground autonomous apparatus for the Red Army. The designer agreed to participate in this project, after which he was provided with unlimited funds and human resources. And after a year and a half, the prototype of the underground boat passed acceptance tests. The autonomous operation of the underground self-propelled vehicle was designed for a week. This limitation was dictated by the supply of oxygen, food and water for the crew. However, due to the outbreak of the war, Strakhov had to switch to the construction of military facilities, and work on such a tempting project was suspended. The further fate of the underground boat was unknown to the designer. The further fate of the underground boat was unknown to the designer. The further fate of the underground boat was unknown to the designer.
Meanwhile, in Nazi Germany, an intensive search for a superweapon was conducted, one of the variants of which was combat underground boats, codenamed "Subterrine" [1] and "Midgardschlange" [2]. The underground apparatus "Midgardschlange" was developed as a superamphibian capable of moving on the ground, underground and under water at a depth of 100 meters. This underground boat was a versatile combat vehicle, and consisted of a large number of modules connected to each other. The total length of this apparatus was 400 - 520 meters and was determined by the tasks set. In fact, it was a real underground cruiser, the mass of which reached 60 thousand tons. According to some, the development of this underground boat began in 1939. This combat vehicle had on board a large number of mines and charges, 12 coaxial machine guns, underground combat torpedoes "Fafnir",as well as reconnaissance torpedoes "Alberich". In addition, there was a small transport shuttle for operational communication with the surface "Laurin" and detachable projectiles for sinking heavy sections of soil "Mjolnir". The crew of the underground vehicle consisted of 30 people, while its internal structure corresponded to the layout of the submarine compartments. Its power-to-weight ratio was provided by 14 electric motors with a total capacity of 20 thousand horsepower, as well as 12 additional engines (3 thousand horsepower). As a result, the "Serpent of Midgard" had to develop a maximum speed under water up to 30 km / h, and under the ground - 10 km / h. After the end of the Second World War in the Königsberg area, unknown adits were discovered, next to which were the remains of an exploded structure. There is reason to believethat these were the remnants of the "Serpent of Midgard" - "Weapons of Vengeance" of the Third Reich.
In Germany, there was another, less grandiose, but also interesting project. The project was called "Sea Lion", [1] and the patent for it was registered by the German engineer and inventor Horner von Werner back in 1933. According to the plan of von Werner, his underground boat was supposed to move at speeds up to 7 km / h and carry a 300 kg warhead both underground and under water. Her crew consisted of 5 people. This invention was classified and transferred to the archives, where in 1940 it was found by Count von Staufenberg. By this time, Germany had developed Operation Sea Lion, the meaning of which was to invade the British Isles. In this regard, an underground boat with a similar name was very timely. The idea was that this unit with saboteurs on board could cross the English Channel invisibly to the enemy and, having reached Britain,go under the English land to a given place. However, to the great happiness for the British, these plans were not destined to come true. Luftwaffe chief Goering convinced Hitler that his aviation would independently bring Britain to its knees. As a result, Operation Sea Lion was canceled, the project was consigned to oblivion, and Goering was never able to fulfill his plan.
[1] project of H. von Wern and R. Trebeletsky
[2] The Serpent of Midgard, Ritter's project