Fortress Europe- European Fortifications Of World War II

by J E Kaufmann

  The Germans counted 142 completed casemates and gun positions, 248 anti tank casemates and bunkers, 2,572 machine gun casemates and bunkers. The majority of the bunkers probably provided frontal fire.

  2. The Molotov Line

  The border defenses were probably the most modern positions built by the Soviets, who were only able to complete and arm a small percentage. The URs on the border had a greater depth than those of the Stalin Line and included a main defensive line of permanent fortifications backed by a rear line of field works. The main line covered from 6 to 10 km of front, had a depth of up to 10 km, and was organized around cores of up to five strong points forming a new type of fort. The strong points consisted of about fifteen to twenty permanent combat blocks. Almost half of the border positions were to be armed with anti-tank guns. In addition to these strong points, the Russians planned to build a number of artillery casemates for two 76.2-mm guns. However, by the summer of 1941, few of the URs were completed.

  When completed, these large works were to include their own usine, gas protection, filters, heaters, stoves and other equipment to make them self supporting. The new works also had better drainage systems and decontamination facilities while periscopes, radio equipment, and underground telephone communications were also planned.

  Although turrets for 75-mm and 76-mm guns were begun, none were ready in time for the war. It is claimed that in the rush to complete the line, the army brought in heavy weapons from the coastal defenses. In a small number of bunkers, cloches were installed.

  According to a German war-time report, 68 artillery casemates and positions, 460 anti-tank gun casemates and bunkers, and 542 machine gun casemates and bunkers were completed in the four military districts on the border. More defenses were added to the old fortress of Brest-Litvosk and the border defenses were strengthened with anti-tank ditches, wire obstacles, and many types of anti-tank obstacles."

  Some of the anti-tank obstacles included heavy wooden posts sunk into the ground at an angle in two rows, boulder obstacles similar to those used by the Finns, Czech hedgehogs and a Russian version of "dragon's teeth." Anti-tank ditches were also used.

  Other new positions were prepared further inside the border after the German invasion. It appears that the ground work for these new positions was prepared before that. Along the Dnepr and east of Smolensk, field fortifications quickly went up soon after the invasion and a permanent line, the Mozhaisk Line, begun about 100 km west of Moscow. This line included small concrete and log bunkers built with concrete front walls and foundations, and log rear walls. In some of these bunkers the logs formed cribs that held rocks that increased the strength of the wall and may have been even stronger than the concrete wall with the weapons embrasure. This building method may have been adopted to expedite construction in the face of the rapid enemy advance.

  3. The Coast Defenses

  Kronstadt, the main naval base on the Baltic stood on Kotlin Island, 20 km west of Leningrad, on the mouth of the Neva River. A number of forts and batteries on the island, on the sea, and on the mainland to the east and west encircled the base. Since 1893 the main forts had included. the Rif Fort on the west end of the island with its two armored turrets mounting two 12-inch Model 52 guns each, a four gun battery of electrically loaded 10-inch Model 00 guns, two batteries with two 6inch Model Canet guns on each flank, and a 75-mm anti-aircraft gun battery. Fort Shants (Schanz) mounted eight batteries, including two batteries of four relatively modern 120-mm Vickers guns each, and two batteries of six obsolete Model 1877 9inch guns. It also had sixteen obsolete 11-inch Model 77 and Model 88 mortars. A number of gun batteries with older weapons dating from 1877 to 1915 remained in service in many of the positions, along with 6-inch Model Canet gun batteries. The Demidov Battery on the southwestern part of the island consisted of six obsolete 9inch Model 77 mortars and six 6-inch Canet guns. Forts Number 1 through 7 blocked the passage between Kotlin Island and the mainland to the east, and included mostly batteries of 75-mm and 76-mm naval and anti-aircraft guns. The old 3-inch gun batteries of these forts were removed during the 1930s. Fort No. 4 had a two gun battery of 120-mm Vickers guns. A number of the forts also had 150-cm searchlights. In addition, a stockpile of sea mines was maintained at several of the forts. The large number of anti-aircraft batteries primarily protected the fleet.

  In January 1941, Fort Pervomaisk.i ("May First"), northeast of Kotlin Island and just off the mainland, was armed with five ancient 11-inch guns that were supposedly replaced by modern weapons, and also twelve 6-inch guns and six 130mm guns. It also had two twin gun turrets mounting Vickers 8-inch guns. Fort Krasnoarmeiski ("Red Army"), another island fort just off the north coast of Kotlin, was similarly armed.

  On the mainland, in the Yhinmaki-Shepelevo area, stood several heavily armed coastal forts. One of these, Fort Krasnoflotski ("Red Fleet"), had two turrets mounting two 12-inch guns each, four single 12-inch gun turrets, a battery of old 10inch Model 00 guns, and three 120-mm Vickers guns. Further west, Fort Bukharin mounted three 6-inch Canet guns and four 120-mm guns. Not far away, Fort Pulkovo had two turrets mounting two 8-inch guns each. Shepeleov, the last fort in this sector, had at least two turrets mounting 14-inch guns and four 120-mm Vickers guns.

  A prototype of a 406.4-mm gun at Leningrad's naval proving grounds took an active part in the defense of the city in 1941. Floating Battery Tallinn was actually the unfinished German cruiser Liitzow, which mounted three German 203-mm guns. One of the coastal positions is purported to have mounted a three gun battery of 14inch (355.6-mm) guns installed in the 1930s.

  On the Finnish coast, the Hango peninsula, taken as part of the peace terms of the Winter War, provided a dominant defensive position for the Soviets. The Soviet navy planned to arm Fort Russaro near Hango with 12-inch guns in 1941. The fort had batteries of 130-mm (or possibly 152-mm guns). The defenses at Hango also included batteries of 152-mm and 234-mm guns. Many other positions were still under construction at the time of the German invasion.

  The Soviets also took over the old fortifications in Estonia, including Fort Aegna with its four 12-inch gun and several 6-inch and 130-mm guns and Fort Suurop with its four 234-mm guns. The Soviets were working on four 12-inch gun positions in 1941 at Fort Naissaari on the island of the same name, which already had eight 6inch guns. Fort Aegna and Naissaari guarded the approaches to Tallinn (Reval). The Russians also set up 14-inch, 180-mm guns, and four 6-inch rail guns at Fort Paldiski. Eighteen other forts and batteries were built or improved and they were armed with 130-mm, 180-mm, 203-mm and 12-inch guns. All these positions received additional anti-aircraft defenses.

  The Soviets set up six positions in Latvia. According to intelligence reports, they moved tubes for twenty-eight heavy guns, probably of 12-inch caliber, into Latvia in August 1940. Several old forts, including Fort Dunamunde, defended the mouth of the Dvina River north of Riga. In the Gulf of Riga the Soviets set up installations such as concrete emplacements for weapons and munitions storage and improved other facilities on the islands of Osel, Dago, Moon, and Worms. They also installed a new 185-mm battery on Osel, two twin gun turrets for 185-mm guns at Sorve, and batteries of 132-mm and 185-mm guns with gun shields on the south side of the island. They also took over the old battery of the port of Libau at the western side of Latvia and turned it into a stronger position by adding a battery of four 132-mm guns."

  In the far north, coastal batteries mounting 305-mm, 240-mm, 155-mm and 100-mm guns defended Murmansk, and batteries that included 210-mm and 150mm guns covered the approaches to Archangel.

  On the Black Sea, there were several major strong points in the early 1930s. One of these, Odessa, received a 152-mm gun battery with observation bunkers and searchlight, a couple of batteries of 185-mm cannons with observatories, armored positions, and a battery of 203-mm guns. Further east, on the mouth of the Dnepr, was the fortified naval base at Otschakov, which included a couple of batteries of 203-mm guns with searchlights and other smaller artillery batteries
.

  Finally, the fortress of Sevastopol on the Crimea with its ring of forts and coastal batteries covered a circumference of about 10 to 12 km. Six heavy coastal batteries, two located north of Severnaja Bay, reinforced other coastal positions such as three old coastal forts on the north side of the position and three on the south side. Coastal Battery Shiskov, completed in 1912, mounted four 120-mm guns on pivots mounted on concrete platforms. Naval Battery Mamaschai (Coast Battery #10), completed in 1930 and one of the newer positions, mounted four 203-mm guns with gun shields on an open concrete platform similar to most of the other coastal batteries. Coast Battery #18, completed in 1917, and Coast Battery #19, completed in 1924, mounted four 152-mm guns each, and Coast Battery #3, two 130-mm guns. Fourteen new or reconditioned old forts, most of them north of the bay, and 3,600 concrete and earthen positions supported by about 350 km of trenches and thousands of land mines, completed the fortress in early 1942. Trenches and tunnels linked many of the positions. In the Sapun Mountains, at the base of the peninsula where Sevastapol was located, natural and man-made caves in the high, almost perpendicular, bluffs of the Tshornaya River were turned into formidable defenses.

  In addition, the Maxim Gorky I and II (Coast Batteries #26 and #25), each had a pair of gun turrets: the first with twin gun turrets located east of Ljabimorka (north of the bay) and the second with a set of similar turrets situated on the southwestern end of the peninsula where Sevastopol stood. Battery Strelitzka mounted six 254-mm guns. Fort Stalin and Fort Lenin included a battery of four 76.2 antiaircraft guns. Other forts, such as Fort Volga, served as infantry positions. Finally, the old strong point of Malakoff was turned into an artillery and infantry position with two 130-mm guns with shields. Besides the normal anti-infantry and anti-tank obstacles, the Soviets employed a "flame ditch," a concrete lined ditch where fuel funneled through a pipe was ignited, creating a fire barrier.

  Although it was not actually a coastal defense sector, the isthmus linking the Crimea to the mainland was defended by the Perekop Line, consisting of permanent works forming two continuous lines. In the low lying treeless plain, every rise over 10 meters dominated the area. The 15 km wide northern belt included the outpost of Perekop. The main defensive area, the 400 year old Tartar Trench, cut through the isthmus and served as a moat supported by two dams. The ditch was about 9.0 meters deep, 20 meters wide and was filled with water. The southern position, which crossed the isthmus taking advantage of the local lakes and canals, was supported further to the south by the Tshetarlyk River. Numerous bunkers covered barriers of steel anti-tank rail obstacles, tank traps, and mine fields. Unlike many of the positions on the border, these were already camouflaged and difficult to detect.

  WEAPONS AND EQUIPMENT

  According to German documents, the so-called 76.2-mm Fortress Cannon on a special ball mount in a gun casemate, replaced the older 76.2-mm gun used in fortifications and had a faster rate of fire. The mount included a funnel that carried the used shell into the fosse in front of the gun position. The older gun positions on the Stalin Line did not have this type of funnel, but included an embrasure cover that dropped in front of the gun.

  The mortars and most of the artillery were placed in field fortifications made of earth and logs. Many of these positions were probably not prepared until after the invasion in 1941.

  In addition to these weapons, there were also small flame throwers, static weapons buried into the ground with only their nozzles exposed and ignited electrically or by trip wire. They were placed in front of the defensive position or among the obstacles. According to German sources, the Soviets used a 1941 design, which means that it is not likely that they were in the Stalin Line. However, they may have been placed in other positions such as the Minsk to Moscow highway or the Mozhaisk Line.

  WORLD WAR II

  The Germans, who invaded the Soviet Union on June 22, 1941, were not fully aware of the defensive positions that faced them. They estimated that 40% were completed, but had no drawings showing exact locations or composition of Russian installations, except for those located right on the border.

  The staff of the German 8th and 29th Divisions had little knowledge of the condition or existence of Russian fortifications behind the Popily and Niemen Rivers. They planned to deal with any fortifications they encountered with massed artillery bombardment from twenty-nine heavy batteries, including eleven 210-mm mortar batteries.

  The Germans easily overran the first bunkers, which were empty, poorly camouflaged, exposed in open terrain, and devoid of obstacles. The Germans smashed the bunker embrasures with anti-tank guns and destroyed many with flame throwers and demolition charges. The 8th Division quickly overcame most opposition on its front with these methods. Grodno fell on June 23 after all the bunkers in front of it had been eliminated. The 28th Division simply bypassed many Russian fortifications at Dorgun on the first day and moved to the Niemen. This division was later ordered to take the strongest border defenses in the area, the Sopockinie fortifications, which it had previously bypassed. After bitter fighting, Sopockinie was taken on June 24. Troops in a three-level bunker resisted for seven hours in the face of the German troops and engineers who detonated several hundred kilograms of explosives. The Germans attributed their success to insufficient Soviet troops in the area and to the incomplete state of the defenses, which lacked obstacles, minefields, and camouflage.

  The old fortress of Brest-Litovsk, located on four islands with wide moats and old walls, was put back into service by the Russians soon after they occupied it in 1939. The German 45th Division attacked it, supported by huge 210-mm howitzers and two 600-mm mortars. After a river assault, the German troops encircled it, but it took them seven days of intense fighting to take the citadel, since they had underestimated the strength of the old works.

  Further to the south, the Germans attacked the Sokal defenses on the Bug River where the Soviets had completed and camouflaged many of the bunkers. On the first day, the Germans methodically eliminated each position, leaving an engineer battalion behind to complete the work the next day. On June 25 twenty two- and three-level bunkers, which were still incomplete, went back into action. Even though they lacked camouflage, they managed to resist for a considerable time. One of the bunkers with a cloche proved particularly difficult to disable. The Germans used demolition charges to eliminate many of them. The procedure required engineers to advance under cover of flame-throwers and place demolition charges in the ventilation shafts, blasting the entrances.

  The URs of Kiev gave stiff resistance from July to August 1941 with the city of Kiev holding off several assaults until August. Further north on other parts of the Stalin Line, many of the URs such as Slutsk, were little more than skeletons, of little use to the Soviets despite Zhukov's pre-invasion efforts.

  The defenses on the Dniestr extended up to 10 km in depth. Along the east bank of the Dniestr the Germans encountered elements of the old Stalin Line. The defenses near the river lacked an outpost line. Two- and three-embrasure light bunkers for machine guns and a few gun emplacements, stood 400 to 2,000 meters apart in the Yampol sector (UR of Novogrod-Volynski) and were reinforced by field fortifications.

  Elements of the German Eleventh Army in pursuit of Soviet troops retreating from the Pruth River, encountered these works in mid-July. Two infantry divisions attacked across the defended river crossings on July 18 at Cosauti and General Poetash. The Germans successfully forced a crossing at both points. Assault engineers eliminated the bunkers at Porohy with the use of flame-throwers and pole charges placed against the embrasures. Heavy explosive charges reduced the remaining bunkers. Russian troops continued to fight desperately even when out flanked and in a hopeless position, not knowing that the high command had already sacrificed them before the invasion began. German reports indicate that the Soviets reoccupied abandoned positions in places where local resistance was strong. In some instances, however, the troops turned out to be raw recruits forced to defend bunkers unfamiliar to them
and they surrendered quickly.

  A heavily fortified area of the Stalin Line at Dubossary, containing many bunkers, artillery batteries, and other supporting positions, finally fell at the end of July. German engineers and infantrymen, supported by anti-tank and anti-aircraft weapons, engaged in close combat, finally overcoming Soviet resistance.

  In September, the Germans penetrated the position they called the Leningrad Line and struggled on. The Mozhaisk Line, the defenses in front of Moscow, was still incomplete and fell quickly in October. For the most part, the Soviets failed to use effectively the fortifications between the border and Moscow, partly because most were incomplete and not fully manned. Odessa, which had only field fortifications and no permanent landward fortifications, resisted until November 1941.

  After the Germans overran the Perekop Line on the isthmus leading into the Crimea in October 1941, it was only a matter of time before Sevastopol fell. It held out for twenty-eight days in a battle that ended in July 1942. At Sevastopol the Germans deployed their super heavy artillery, including the 800-mm rail gun Dora, to destroy key points like Maxim Gorky I. On June 6, heavy German guns and mortars fired on Maxim Gorky I and scored direct hits that destroyed one of the gun turrets and damaged the other. Additional artillery fire and air bombardment failed to eliminate the Maxim Gorky damaged turret, which was finally put out of action by assault engineers on June 17. The battle for the battery continued as the Russians fought from its battered positions until July 1. The 800-mm monster rail gun inflicted little damage beside landing three rounds on Fort Stalin on June 5, and fifteen rounds on Fort Molotov on the next day. German heavy artillery concentrated on Fort Stalin on June 11-12. The four 76.2-mm guns of the fort had special shelters and remained in action until June 13 when an infantry assault finally took the fort. By early July, the Germans had fired over a million rounds. They had taken over 3,500 fortified positions, 7 armored forts, 38 bunkers built into the rock, 118 bunkers of reinforced concrete, and another 740 built of earth and stone. On July 4, after taking the Sapun positions, and the final assault that took Maxim Gorky II, the campaign against the last major pre-war fortified position came to a close. Soviet methods of fortifications began to change as the war progressed.