Mannerheim Line
The Mannerheim Line ( Finnish. Mannerheim-linja) was a Finnish line of defense between Lake Ladoga and the Gulf of Finland across the Karelian Isthmus in the winter war of 1939/40 (attack by the Soviet Union on Finland ) . The fortification did not have an official name. The name Mannerheim-Linie after the Finnish Commander-in-Chief Carl Gustaf Emil Mannerheim probably comes from the officer Jorma Gallen-Kallela, who used this expression in the autumn of 1939 with foreign journalists.
Tactical and technical information
The Mannerheim Line was 136 km long and can be roughly divided into two sectors: Firstly, fortifications on the northern side of the lakes Vuoksi and Suvanto and, secondly, fortifications to block land roads (especially the Taipale sector between Lake Ladoga and Lake Suvanto and Sector Summa- Lähde as a barrier to the so-called Vyborg Gate between Leningrad and Vyborg ). The fortifications along the lakes together with the Taipale sector held up to the end of the Winter War; they were never broken.
The fortifications comprised of passive elements 440 km of trenches , 331 km of barbed wire obstacles, 136 km of all types of anti- tank barriers and 823 shelters, 19 of which were made of concrete. Active elements were six cannon bunkers (all made of concrete, three each north of Lake Vuoksi and three north of Lake Suvanto), 648 machine gun positions (of which 42 made of concrete and of which in turn six multi-machine gun bunkers with three or more machine guns) .
Overall, the Mannerheim Line was just a chain of field fortifications that lacked depth. Concrete systems made up just under four percent of their elements. Both active and passive combat strength were much lower than that of the Maginot Line or the West Wall .
Types and characteristics of the bunkers in the Mannerheim line
The oldest bunkers, built between 1920 and 1924, were of the so-called Enckell type (after the then Chief of the General Staff, Gen.lt. Enckell), d. H. Concrete structures armed with a machine gun and designed for frontal fire. You should be able to withstand three direct hits with 150 mm bullets. The greatest danger was shooting into the relatively large and non-closable loopholes .
From 1930 bunkers of the Casemate de Bourges type were built. These systems had no loopholes to the front, but only to the sides and back, and the loopholes were protected against fire by "wings" made of concrete. The “Casemate de Bourge” bunkers could hardly be wounded by artillery, but could only fire flank fire and were not able to defend themselves against an attacker who came directly from the front and “climbed onto the roof” of the bunker, so to speak. So they needed cover from neighboring bunkers or field fortifications . The best-known building of the Casemate de Bourge type was the multi-MG bunker "Miljoonalinnake" ("Million Bunker", because of the high costs) in the Summa-Lähde sector. It was lost after all neighboring facilities had been destroyed and Soviet soldiers detonated around two tons of explosives on the roof of the bunker.
The third and last type can be found in just one example, the "Poppiuslinnake" bunker ("Poppius-Bunker", named after the commander Lt. Poppius) in the center of the Summa-Lähde sector. With two machine guns from two casemates, he was able to fire both frontal and flank fire. The loopholes were narrowed to seven centimeters wide and protected with 32 cm thick armor plates, which could withstand even the heaviest projectiles. However, these records were extremely expensive and had to be bought abroad, so that one copy remained.
None of the bunkers had armor-piercing weapons. That turned out to be a serious shortcoming; the attacker could drive up to the loopholes with tanks and block them (in this way the "Poppius bunker" was lost). Because of this, all the bunkers needed the support of fighters outside, who fended off approaching tanks with incendiary bottles or concentrated loads.
Attacks on the Mannerheim Line, breakthrough
After the start of the Winter War, the Red Army attacked the Taipale sector between December 6 and 11, 1939, but failed. Taipale lasted until the end.
Between December 17 and 20, 1939, the Summa-Lähde sector with six divisions , one tank corps and two tank brigades was attacked without success. On the main day of the battle, December 20, the Red Army lost 58 tanks, 22 of them heavy, without being able to overcome a single bunker.
After that, the Mannerheim Line was continuously bombed and shelled.
After the forces were refreshed, the attacks began again on February 1, 1940. From February 6, the focus was on the Summa-Lähde sector. On February 12, around 5 pm, the “Million Bunker” was lost, while the “Poppius Bunker” on the Leningrad-Vyborg road was able to hold out for another five days. The capture of this bunker on February 17, 1940 at around 1 p.m. is considered a breakthrough through the Mannerheim Line.
The Mannerheim Line had withstood a numerically very far superior opponent for exactly two months.
More pictures
Entrance to the bunker Le 7.
Bunker SK10 in 2017.
Entrance to the SK10 bunker in 2017.
