Fortress Europe- European Fortifications Of World War II

by J E Kaufmann

  By the mid-1930s these fortifications became known to the outside world as the Stalin Line. Gradually eleven of the thirteen original pre-1938 URs were eliminated, and by late 1940 the line was reduced to a mere shell. The weapons and equipment of most of the positions was sent either to the new border positions, or into long term storage. According to some reports, thousands of emplacements were blown up, covered with earth, given to collective farms for storage, or left under guard. The truth is that the army probably did not have much time to waste demolishing thousands of bunkers, nor is it likely that many of these positions actually provided enough storage space for agricultural needs. Many of the larger positions were preserved, but inspection reports indicate that they were overgrown with vegetation and that their equipment had deteriorated.

  The Poles later called the Soviet defenses on the new border the Molotov Line. Russian workers labored on its construction on the actual border, literally in sight of the enemy. By 1941 the number of URs on the new border was increased to nine. Surveys for three new URs in Bukovina and Bessarabia were carried out in the spring of 1941, but resources were not committed for their construction until much later.

  Large numbers of civilian laborers began to work on the Molotov Line in earnest in 1940. The local population was rounded up mainly to dig anti-tank ditches and set up other obstacles. In the meantime the authorities attempted to impose security around the building sites. The new Baltic SMD, Western SMD and Kiev SMD were given priority, receiving up to 140,000 civilian laborers. In some cases, like the Bialystok salient, soldiers set to work on the defenses. The construction units of the old Stalin Line were also moved forward to the Molotov Line.

  Soviet industry could not meet the demands for raw materials needed for construction, so most work was not completed by the summer of 1941. In fact, only 25% of the positions of the Molotov Line were actually completed by the time of the German invasion in June 1941. A number of these positions were designed to hold field weapons and, according to some sources, almost a thousand held artillery. The remainder of the 2,300 combat shelters were armed with machine guns. Even though the Russians were good at creating defensive obstacles, they failed to install sufficient minefields on the Molotov Line. This was probably due to the fact that the military engineers did not have enough equipment and mines available to do the job properly.

  According to Soviet military doctrine, the best defense was offense. For this reason troops were massed near the frontier while work continued on the fortifications during 1940. In January 1941 the top military leaders of the Soviet Union such as D. G. Pavlov the Russian tank expert, Georgi K. Zhukov the commander of the Kiev SMD, and Defense Commissar Timoshenko took part in a series of war games. These exercises proved that Pavlov and his supporters' doctrine of first strike could lead to disaster. Stalin, already alerted to the planned German invasion, apparently accepted Zhukov's and Timoshenko's idea of using a deep battlefield and preparing to meet the enemy with counter thrusts. Zhukov, who became the Chief of the General Staff, decided to reopen part of the Stalin Line and even add some new positions.

  There is some evidence to indicate that work may have started on a deeper line of defenses that began as far east as Mozhaisk on the road to Moscow and included other sections along the Desna River to the Dnepr'. The Mozhaisk Line, according to the official history, was begun by order of the Military Council on July 18, 1941 and was to include three main defensive areas consisting of two lines between 30 to 60 km apart. The line's concrete bunkers usually took a single machine gun or antitank gun, and many were of a simpler construction. The line was still not completed by October. The Soviets claimed that 296 blockhouses and 535 bunkers were built with 170 km of anti-tank ditches, and this was supposedly only 40% of the emplacements planned.

  German intelligence maps show a "Leningrad Line" running from the coast southwards to Krasnogvardeysk. According to a German document entitled Russian Combat Methods in World War II, a post-war report made for the U.S. Army, the line, which was very strong in this area, consisted of many earth and concrete bunkers "with built-in guns and other heavy weapons." In addition, there were "concrete pillboxes with hand operated disappearing armored cupolas for artillery and machine guns." Furthermore, an anti-tank ditch over 6 meters wide, 4 meters deep, and several kilometers long was strengthened with bunkers at every bend and two more anti-tank ditches behind it. According to German sources, this position had been prepared long before the Nazi troops ran into it in September 1941. It may have been part of Zhukov's plans for a deeper defense line which included the positions previously mentioned as in front of Moscow. It is obvious that Stalin certainly had not intended the Leningrad Line, with its anti-tank ditches and obstacles, to be a deterrent to a Finnish amphibious or flanking invasion, especially since Finland did not have the tanks and troops necessary for such an operation.

  Pavlov, commanding the troops on the border and on the fledgling Molotov Line, did not realize that they were to be sacrificed. Zhukov, retrenched in his own position, did not allow the transfer of additional artillery from the Stalin Line to the border defenses. In late February 1941, at a meeting of the Supreme Military Council of the Red Army he had argued against the transfer of the weapons and the equipment to the border defenses, the artillery in particular. Stalin settled the argument in favor of Zhukov, and the artillery remained in its old positions of the Stalin Line despite claims to the contrary. On April 8 Zhukov directed six of the seven new URs in the Western SMD and Kiev SMD to be activated within two weeks of the outbreak of war even if none were completed. The installations were readied for combat even though most could not be fully equipped because of shortages of equipment and personnel. At the same time Zhukov ordered the quick arming of the border positions and the installation of armored doors on the bunkers to make them defendable. He realized that there was little time left, and that the border positions near completion had to be ready even without the equipment necessary for prolonged resistance, otherwise they would be of no value at all.

  A July 1941 American intelligence report included a map showing the Soviet fortifications running from the Pruth River and along the entire border to the Baltic, incorrectly identifying all the defenses as temporary field fortifications. On the map, the line from Leningrad to the Dnestr, that is the Stalin Line, was identified as the first line of permanent defenses. Most interestingly, a second line was shown behind the Stalin Line consisting of some of the older URs of the pre-1938 Stalin Line in the Ukraine and along the Dnepr sweeping eastward from Novoskolniki, through the Valdai Hills, to the Volga. It was labeled as the second general line of permanent fortifications and may actually represent concrete evidence of Zhukov's defensive strategy.

  The Soviet Union began strengthening its fortifications along the Baltic Sea in the summer of 1939, setting up new batteries and defenses, and modernizing several positions. The Baltic Coastal Command was headquartered at Kronstadt. The forts were concentrated in three areas: Sestoretsk-Izhora on the south side of the Gulf of Finland, the Krasnaya Gorka-Shepelevo area, and the Kopore-Luga area. The key area of fortifications on Kotlin Island centered at Kronstadt, the "Malta of the North," guarded the approaches to Leningrad.

  As a result of the Finnish War, the Soviet Union obtained a lease at Hango where they set up a base. In the Baltic States, old forts were restored and new positions were replaced. The Soviet occupation of Estonia also brought an end to 1939 Finnish and Estonian plans to close the Gulf of Finland by using heavy 305mm gun batteries at Aegna and at a planned site at Maissaari, and at Forts Makiluoto and Kulvassari.8 Both Estonian batteries had been completed in 1917 and destroyed after the war. Aegna was restored to service in the 1920s and work continued on the Maissaari site through the 1930s.

  In February 1941, the Soviets began to build the concrete coastal defenses in the Baltic States on the islands of Osel, Dago, and Moon to guard the entrance to the Gulf of Riga and other important points in the newly occupied territories. Batteries of
132-mm guns with gun shields were set up on concrete positions, and coastal defenses were also established on the approaches to Tallinn (Reval) and nearby islands. In the far north, the coastal batteries at the ports of Archangel and Murmansk, were separated by a large stretch of inhospitable coastline.

  In the south the Black Sea fortress of Sevastopol was well defended. Two large 305-mm gun turreted batteries of Maxim Gorky I and II were begun between 1912 and 1917 and completed between 1928 and 1934. New positions were added to strengthen the old defenses of Sevastopol. A fortified base was set up at the mouth of the Dnepr and the port of Odessa received several coastal batteries.

  Robert Tarleton believes the Stalin Line was not ready for combat. The Kiev SMD was the strongest at about 80% strength and with 650 of its positions still in existence in the URs of Korosten and Novogrod-Volynski in June 1941. Further north, only 70 unarmed bunkers in the Ostrov UR, and 75 in the Sebezh UR of the Baltic SMD were ready. According to German estimates, 120,000 border troops were positioned between the North Sea and Black Sea, in the summer of 1941, 12,000 of which were in the Karelia and Leningrad districts, 15,000 in the Baltic district, 24,000 in the Western SMD, 20,000 in the Kiev district, and 12,000 on the Rumanian border, in the Odessa district. Their mission was to guard and man the border defenses in the event of war. There was also a major shortage of officers and NCOs, which amounted to 50% in some cases. Soviet sources indicate that the URs of Polotsk, Minsk and Mozyr in the Western SMD were manned by approximately two machine gun battalions in June 1941. The Kiev SMD had two machine gun battalions and five caponier artillery platoons in the UR of Korosten. The Novogrod-Volynski UR (Zwiahel) had a machine gun battalion and ten caponier artillery platoons. The units assigned to the URs, also referred to as UR units, normally included two to four machine gun battalions and smaller artillery caponier units. It appears that many of the URs of the Stalin Line were at about 30% strength. Its normal garrison was supposed to be twenty-five machine gun battalions for the thirteen URs. Apparently, few if any of these UR units had been deployed on the Molotov Line.

  DESCRIPTION

  1. The Stalin Line

  The Stalin Line covered 1,835 km and included over 3,000 positions, twice the length of the Maginot Line but with less than half the number of combat structures. While the French built 7.7 positions per kilometer, the Soviets built only 1.7.

  Although the URs had some depth, most were designed for independent operation and were not meant to coordinate with neighboring URs. The core of the defensive structure of each UR consisted of a number of strong points consisting of fifteen to twenty (or more) independent combat positions and covering up to 1.5 km of front and a similar depth. A group of strongpoints formed what was referred to as a Battalion Defense Area since a machine gun battalion along with smaller artillery units was normally assigned to it. This defense area covered a sector of up to 10 km and a depth of 6 km. The number of Battalion Defense Areas varied; the UR of Polotsk had at least six and the UR of Minsk appears to have had five large battalion areas, but several of these were divided into two sections. The new UR of Slutsk had six.

  The heaviest works consisted of forts that occupied key positions. These forts had underground works and supported several combat blocks in a set-up somewhat reminiscent of French, Czech, and Swiss works. One of these Soviet subterranean forts, Fort A or Hulsk about 10 km south of Zwiahel, was built early in the 1930s and exhibited some of the weaknesses typical of pre-1938 positions. Blocks 101 and 102 had three embrasures each for a heavy machine gun, Blocks 100 and 104 were machine gun casemates with two embrasures giving flanking fire, Block 98 was a single-embrasure bunker while Blocks 98, 101, and 102 gave frontal fires across the Slucz River. However, none of these blocks effectively covered the others. The artillery consisted of two 76.2-mm field guns in Block 99 and Block 103. Both the artillery casemates firing to the flank were similar to the French style, but were apparently not as well designed. The Russians called these casemates "half caponiers" when they fired to one flank and "caponiers" when they covered two flanks. Block 103 supported machine gun position 105 located on a bend of the river, further downstream. The other casemate supported a couple of DOTs (bunkers), and was within range of one of them. Nonetheless, there was a lack of sufficient mutual support and the rear of the fort was left unprotected. Field fortifications filled the intervals.

  The combat blocks were rather small. Casemate 100 had an emergency exit and an interior about 1.3 meters wide and 3.6 meters long. Its outer wall was 1.5 meters thick. Blocks 101 and 102 also had emergency exits and a firing room with one crenel, and a main firing room with two crenels. Even though they faced the enemy, the walls were only 1.5 meters thick, which was satisfactory for small independent positions, but below the norm for blocks of most west European forts. Artillery Block 103 was larger, with a width of 9.8 meters and a length of 12.4 meters. Its two gun embrasures were staggered along the narrowest part that also included a small entrance. The gun rooms were 3 x 3 meters and a munitions room was located to the rear of the block. The walls and roof, 1.5 meters and 1.0 meter thick respectively, where even thinner than in the machine gun positions, where the roof was 1.1 to 1.5 meters thick.

  Fort A occupied a hill and its blocks were connected to an underground tunnel through vertical shafts. Its simple, centrally located entrance, stood about 50 to 100 meters behind the main cluster of blocks, and was accessed from a ditch by a flight of stairs. The underground gallery, about 515 meters long, lay about 11 meters below the surface and was lined with concrete panels. It branched out to link all the positions except Block 99. The gallery was 1.05 meters wide and 2.15 meters high and the rooms opening off it had a width of 1.85 meters and a height of 2.45 meters. Several machine gun positions placed at corners in the gallery, protected the interior.

  There were several munitions and filter rooms in the tunnel system. There was also a usine and a filter room with ventilators by the entrance. In addition, the 130 man garrison was provided with gas masks.

  Among the few other examples of these Soviet forts is Fort Serebritsa which was also built into a hill in the Mogilev-Podolski UR, a sector along the Dniestr that remained active after the border advanced to the Pruth. The fort's gallery was 905 meters long and was reached through two entrance blocks. The fort included two triple-embrasure machine gun blocks (470 and 471) and a pair of gun casemates, each mounting two 76.2-mm guns (469, 472). These positions overlooked the river and both machine gun blocks fired forward.

  Some of the other large fortified positions included independent gun casemates, a number of which had their own underground works. These casemates were generally larger than those of the above mentioned forts and were built in 1938 with the new URs, and added to the old URs. They were not however very common in the old URs.

  By 1938, most of the older combat structures had become obsolete while the newer ones might have been satisfactory if enough had been completed. Their concrete thickness and the amount of reinforcing steel rods had been increased, and the quality of the cement had also been improved. Anti-ricochet devices for crenels, standard on most western fortifications, were introduced and similar protective arrangements were planned for the entrances.

  Soviet permanent fortifications were classified according to the following categories:'

  Light - resists infantry weapons

  Reinforced - resists 76-mm guns aid 122-mm howitzers

  Medium - resists 152-mm howitzers and 100 kg. bombs

  Semi-Heavy - resists 200-mm projectiles and 500 kg. bombs

  Heavy - resists 305-mm projectiles and 1,000 kg bombs

  This demonstrates that the strength of the Soviet works were on a par with many in the west, but the overall designs still lagged behind. The Soviet positions, even more spartan than the crudest shelters in the west, usually lacked the basic necessities.

  The fortified positions of the Stalin and Molotov Lines included at least six types: (1) positions for machine guns firing to the fron
t, although later models were planned for 45-mm AT guns; (2) casemates for flanking fire, called half-caponiers, holding light and heavy machine guns and AT guns (later models were to include cloches); (3) blockhouse for all-around defense;" (4) artillery blocks, also called half caponiers, in single (two embrasures) and double models (four embrasures); (5) command posts and observation positions; and (6) forts or ukrelennyie gruppy usually with smaller combat blocks and subterranean facilities.

  Some machine gun and artillery casemates included a fosse in front of the weapons position, but it is difficult to determine if these were used in both the Stalin Line and Molotov Lines. If they were used in the Stalin Line, the engineers probably did not design them until after 1937.

  A rare description of one of the independent artillery blocks or caponiers is to be found in Small Unit Actions During the German Campaign in Russia, a US Army report prepared by German officers. The block that was described was located behind the Dniestr in the Mogilev-Podolski UR that only fired to the flanks and covered two river crossing positions. Built into a steep bluff, it mounted a pair of 76.2mm guns on each flank, had walls about one meter thick, and was excellently camouflaged. One of its machine guns, located in a concrete embrasure high above the entrance, fired forward. Its garrison numbered about sixty men. There were two underground levels, a usine, and a ventilation system. The position lacked entrenchments and wire obstacles around it. This may well have been typical of many other positions on the Stalin Line in 1941.

  Work on the Stalin Line was abandoned before most improvements could be implemented, and it would be incorrect to assume that these fortifications were of the same quality as those in the west. Nonetheless, many of the Soviet positions proved to be strong enough to impede German progress when they became operational.