Fortress Europe- European Fortifications Of World War II

by J E Kaufmann

  The outpost line ran close to the Italian border with the main line close behind it. The strongest positions included the casemates and artillery positions between Vrhnika (1st Sector) and Zelezniki (4th Sector) which covered Ljubljana. Emphasis had moved to the 2nd Sector near Susak for fear of an Italian assault flanking the Sava River line. The 2nd Sector was almost continuous except for a gap occupied by mountain troops.

  By 1940, the Yugoslavs had to prepare additional fortifications for the Banat area as German troops moved into Rumania. Planning went ahead for fortifications near the Iron Gate. Meanwhile some light defenses were completed on the Bulgarian front to close the Vardar Valley.

  The outpost or advanced post line contained bunkers for the Frontier Guards. These small positions held a couple of automatic rifles and a squad in peacetime. Anti-tank obstacles were usually found about a kilometer to the rear of this line.

  Only the 1st, 2nd and 3rd Sectors included the largest and best equipped positions in Yugoslavia. Work progressed on six forts (Czech type ouvrages or tvrz) in the 1st and 3rd Sectors, but none were finished in time to meet the Axis invasion. The army prepared plans for other interior lines such as one covering Zagreb to the coast, another using the Glina and Czama Rivers behind this line, and finally one behind these following the Ilova and Una rivers. All of these blocked the Sava Valley, but the army only had time to do a small amount of work on these positions. Even less was achieved on one last position along the Drina River west of Belgrade. One post-war estimate from a Polish source claimed that by 1941 only one fourth of all the planned fortifications were actually completed.

  Lack of time and money prevented Yugoslavia from preparing adequate defenses. On the other hand, the modifications and renovations were not sufficient. The Czechs were the main source of armor, including cloches. The heavy cloches were shipped on special rail cars through Rumania from Czechoslovakia to avoid problems with the Hungarians. When Czechoslovakia fell to the Germans, the Yugoslavs had to rely on the more expedient solution of using concrete cupolas instead of steel ones. The Yugoslavs perfected the use of concrete cupolas, although their value was limited. The only item not in short supply was limestone for cement. The Yugoslavs combined French and Czech techniques with their own. One interesting method they used was making walls of two layers of concrete. The outer layer contained a spiral grid to resist projectiles.

  Seventy-two companies of Granicari (Frontier Guards), organized into battalions, defended the frontiers. The peacetime army deployed three brigades and four independent battalions with sixteen batteries to defend the Italian, German, and Hungarian borders. One brigade with five batteries (24 guns), and an independent battalion with one battery (4 guns), for a total of 6,500 men, defended the Italian Front. Another brigade of 2,200 men including three batteries (16 guns) covered the German border. The third brigade with five batteries (30 guns), and an independent battalion with two batteries (12 guns) totaling 6,400 men occupied the Hungarian Front. On mobilization these units expanded to about 50,000 men with 160 guns in forty batteries. The border defenses were intended to delay the enemy for up to three weeks while the army mobilized.

  The Sixth Army was assigned to the coast defenses with naval units. It consisted of a motorized brigade and an independent regiment which on mobilization expanded into a division and brigade respectively. The division was headquartered at Split. Boka Kotor (Cattaro) and Sibenik held coastal defense commands. Although intelligence reports indicated that many coastal sectors were defended, they may have included batteries of obsolete weapons. As late as April 1940 only Kotor and Sibenik had permanent defenses and the others lacked coast artillery and anti-aircraft guns. Split was next in line for armament when it became available. Fortifications for lighter weapons may have been completed by this time in most of these other ports.

  DESCRIPTION

  The French type ouvrages were not completed and only a small number of large concrete positions were built. Most of these were on the Italian front or the coast. Few bunkers had received their armor and thus lacked armored embrasures and cloches. The most effective work done was on the camouflage of the positions and the creation of some anti-tank obstacles. Because of this only a few examples of positions can be given.

  Of the seven ouvrages designed for the Italian front, plans of one, Fort Tri Kralja, are available. The original 1937 document shows fourteen infantry, one artillery and two entrance blocks designed to withstand artillery of up to 305-mm. The layout does not follow the typical French pattern except for the caserne being located to the rear. This fort was to occupy the upper part of a mountain with its combat blocks at elevations ranging from 740 meters to 870 meters. Each block, except for three, were to have cloches. German reports indicate some were to be concrete instead of steel. The entrances appear to have been designed similar to those of the French ouvrages, one for men and another for munitions. Another plan for an entrance shows a mixed entrance with many similarities to those used by the Czechs. The artillery casemates fired to the flank like those of the French, and had two large magazines below. The fort was divided into four combat sections with one on each side of the mountain. The main gallery was to run from the caserne to the four blocks of the combat section on the west side of the mountain. Another main gallery ran from the northern section of the block to the southern group, and the two galleries intersected in the middle of the fort. Plans for the ouvrage changed by 1938, and by 1940 only two small infantry blocks had been built on the west side of the mountain and about 500 meters of galleries and a light caserne excavated.

  Plans for 1941 show another ouvrage named Goli Vrh with two infantry casemates designed like those of the French, although one had a concrete turret. Another plan from 1940 of the ouvrage of Strmica reveals that the caserne area had features more reminiscent of the Czechs. Fort Strmica had also been designed in 1937 as a fort with an entrance block and six combat blocks on a mountain 625 meters high. By 1941 it was reduced in scale to a simple entrance and three small combat blocks for machine guns. It still included most of the planned galleries, amounting to over 300 meters, but the caserne was reduced in scale. It included the standard features found in most Maginot ouvrages from communications room to filter rooms. These ouvrages were to rely on heavy machine guns and, where necessary, a few anti-tank guns. They were not designed for close defense and did not have fosses or other features used by the French and Czechs possibly because of their locations which may not have been easily accessible.

  Other heavy works for the Italian front included a two-level observation block with a cloche and 2.5 meters of concrete protection. An impressive position completed on the same front was a two-level double casemate for machine guns with an underground entrance in a fosse and a concrete turret. The turret's roof was 1.0 meter thick.

  The Yugoslavs planned to have a few heavy machine gun casemates with steel cloches similar to those of the French. The most interesting work appears to be a combination of the French artillery block and the Czech independent artillery block. It was a casemate for four 105-mm howitzers. Unlike the French guns, these were field pieces and given a 60 degree firing angle. This two-level position had a protective fosse in front of it, and at least one of these casemates was nearly completed at Trata on the Italian front.

  The medium works could be for both frontal or flanking fire or all around defense, and were supposed to have armored crenel covers. Some of these were similar to those of the French. They had two levels and more than a single chamber. They were much larger than the light positions, which were mainly for machine guns and normally had only a single chamber.

  Along with their unusual concrete turrets, the Yugoslavs also created a unique armored position in concrete. It consisted of a turret-like steel structure which had its weapons embrasure lowered by a lever system. When lowered into the concrete the armored back end of the structure raised up to seal the position. One of these positions was found at Radmannsdorf where the concrete structure had two of the
se machine gun turrets and a periscope observation position between them.

  The Yugoslavs created an interesting, if not effective, variety of positions and accessories. With regard to obstacles, they used the standard array, from pyramidal concrete blocks to iron rails in three to five rows. Apparently these rails were not sunk in concrete, but instead just buried in the ground reducing their effectiveness. One example of an antitank ditch had a concrete wall (the counter scarp or outside wall) 3.5 meters high with the ditch almost 8.0 meters wide.

  Sibenik, the best defended port, apparently lacked land defenses to ward off an assault from Zara. It had fourteen coastal batteries, including one with two 280-mm howitzers near the old fortress, and three batteries of 47-mm naval guns (four guns per battery) guarding the narrows. A battery of two 150-mm naval guns was in a commanding positions on Prvic Island. Two batteries of old 120-mm naval guns were southeast of the city. A battery of four 47-mm naval guns was on the northwest end of the island of Zlarin, and a battery of two 150-mm naval guns covered the coast near Zecevo. On the island of Zirje there was a battery of two 150-mm naval guns, and supporting it on the island of Kakan was a battery of two 190-mm naval guns and an army battery of four 100-mm guns. Finally, another battery of four 47-mm naval guns on Logorun Island mounted its own searchlights. Additional searchlights were on Zlarin Island. To complete the defenses a boom closed the narrows leading into the harbor. An underground depot was built for ammunition and mines. All communications with the island positions were made by visual signals.

  Kotor (Cattaro) was the main naval base and was even more heavily protected then the others, but many of its weapons were old and unsatisfactory. It included eighteen coastal and anti-aircraft batteries. These included two single weapon 300mm mobile howitzer batteries with prepared positions. These were old Austrian guns. A battery of four 120-mm naval guns stood on a promontory on the west side of the gulf. Other batteries included 210-mm and 150-mm naval guns, and 47-mm and 70-mm guns. The 70-mm guns were taken from Austrian torpedo boats. One of these batteries had two new Skoda 150-mm naval guns and was on the peninsula of Molunat. The Yugoslavs converted two batteries of 90-mm naval guns into antiaircraft weapons.

  At Kotor was Battery Molunat with two 150-mm L/40 naval guns on concrete platforms. Its supporting munitions and ready rooms were in the mountain. Each gun position had a gallery of from 25 to 50 meters in length leading to it. Below each gun was a ready room, and beneath that a munitions room with a lift which was protected by a concrete cover on the surface. At the third and lowest level was the command room.

  On the other side of the channel leading to Kotor was Battery Kozmac with two 240-mm L/40 Skoda guns in a turret at an elevation of 500 meters. Its entrance was at about 90 meters above sea level with a tunnel that ran several hundred meters to the underground facilities. It also included a battery of three torpedo launchers. These coast defenses were some of the most impressive works made by the Yugoslavs.

  In addition to these positions, the Yugoslavs established an outpost line of observation and signal stations on the coast which held a garrison of about platoon strength and sometimes included 37-mm guns. These were located at Susak and on the islands of Krk, Rab, Silba, Mulat, Dugi Otok, Uljan, Murter, Zirije, Hvar, Vis, Korcula and at Sibenik, Movar, Split, Dubrovnik, Sveti-Ilya, Oboswik and Budva.

  WEAPONS AND EQUIPMENT

  The Yugoslavs had three main types of fortifications. They were rated as heavy, medium, and light. The latter were basically reinforced field fortifications.

  Walls - Front Rear Type Roof (in meters) 2.00-2.75 Heavy IV 2.00-2.75 1.70 III 1.70 1.50 1.00 Medium II 1.50 1 1.00-1.25 1.0 .60-.80 Light - .20-.50 .30-.50 The main types of artillery used were as follows: Weapon Range (in meters) 12,300 305-mm M.16 Skoda Mortar 23,800' 149-mm M. 15/28 Skoda Cannon 11,200 338 155-mm M.17 Howitzer 10,900 120-mm M.78 Cannon 105-mm M.36 Skoda Cannon 18,100* 100-mm M.14/19 Skoda Field Howt 9,800* 9,300 80-mm M.5/8 Field Gun 7,300 75-mm M.7 Field Gun 75-mm M.28 Skoda Mountain Gun 8,700* 4,000* 47-mm Skoda Anti-tank Gun 37-mm Skoda Anti-tank Gun 3,000* Coast Artillery 17,800 240-mm U40 Naval Gun 240-mm M.98 Mortar 6,500 7,300 210-mm M.80 Mortar Resists Weapons of 420-mm 305-mm 220-mm 150-mm splinter proof3

  WORLD WAR II

  By 1941 Yugoslavia found itself in a precarious position when Italy engaged Albania and German troops moved into Hungary, Rumania, and Bulgaria. A diplomatic arrangement with the Germans was rendered meaningless when a coup deposed Yugoslavia's regent, putting the young Yugoslav king in power. Hitler, already concerned about the war between Greece and Italy, wanted to resolve the problem. The situation in Yugoslavia convinced him that the solution included the conquest of Yugoslavia.

  The Yugoslav army hoped to defend all its frontiers and keep a route open through the Vardar Valley to link up with the Allies through Greece. However, the German blitzkrieg began on April 6, 1941, as Yugoslavia continued to mobilize. The advanced positions had no depth and could not check the Axis advance. A threepronged attack coming down the Drava Valley from western Hungary, across the Rumanian border towards Belgrade, and down the Marava Valley from Bulgaria, bypassed most of the Yugoslav defenses and converged on the capital.

  The defection of Croatia actually did not make the hopeless situation any worse. The Italian army prepared to invade with German assistance a few days after the Yugoslavs were on the verge of collapse. The incomplete fortifications contributed little to the defense of the country and may have caused the Yugoslav army to become too dispersed in an attempt to hold on to the defenses of the northern half of the country.

  Yugoslav two level position for 3 MG and an AT gun near Zaier-Tal on Italian border.

  Yugoslav Artillery Casemate for 4 x 105-mrn Howitzer.

  Delivers flanking fire to cover road to Zirovsti Vhr nearTrata.

  Yugoslav two level block for all around defense near Radmannsdorf. Access through a well into lower level.

  Two half-armored half-cloche and two embrasures with armored plates.

  Yugoslav Disappearing Cupola for a Hvy MG.

  Chapter 12

  THE BALKANS

  BACKGROUND

  The Balkans became known as "The Powder Keg" of Europe after the upheavals that took place there in the early part of the twentieth century. Yugoslavia, which is treated in the previous chapter, was largely part of the Austro-Hungarian Empire with the exception of Serbia. The remainder of the Balkans began to break away from their Ottoman Turkish overlords during the nineteenth century. Serbia was virtually independent after the first quarter of the century, while Greece, with the help of the great European naval powers, won full independence in the 1820s. In the late 1870s Rumania and Bulgaria became free of Turkish domination.

  The Balkan Wars began in 1912 when Bulgaria, Serbia, and Greece declared war on Turkey to free Macedonia. Before long Turkey lost most of its European possessions and the Bulgarians stood at the gates of Constantinople. However, Greece, Serbia, and Bulgaria argued over how to divide up Macedonia and the new nation of Albania was created on the Adriatic. After the peace talks, a Turkish revolt caused the war to continue until the spring of 1913. Then in May 1913 the Bulgarians decided to settle their disagreements with their neighbors through force of arms, launching the Second Balkan War. The Bulgarian offensive ground to a halt after two months. Meanwhile, Turkey rejoined the fight in July and Rumania shortly after, when it invaded Bulgaria.

  By the time the conflict ended, the political map of the Balkans had changed significantly. Greece was awarded many of the Turkish Aegean islands, including Crete. Bulgaria, which acquired virtually no new territories, wanted retribution. Serbia and Greece divided Macedonia between themselves. Turkey reestablished its presence in the southeast corner of Europe by holding on to the Bosphorus and Dardenelles. Turkey and Bulgaria aligned themselves with the Germans in World War I while Rumania later found itself on the side of the Entente and the defeated Serbia.

  After the Great War, the newly created Yugoslavia became the larg
est of the Balkan nations. Rumania allied itself with Yugoslavia and Czechoslovakia in the Little Entente to keep Hungary from trying to regain former territories of the AustroHungarian Empire. Bulgaria remained distrustful of its neighbors, refusing to relinquish its claims to the lands it had lost. Greece tried to take advantage of the newly formed Turkish Republic by seizing parts of Ionia, but Turkey firmly held on to its borders. The small, mountainous country of Albania remained a tempting target for Italian expansion.

  The cessation of hostilities brought only an uneasy peace to the Balkan nations. Greece had to contend with Italy in the Aegean and the Adriatic, and keep a wary eye on its Macedonian frontier at the same time. Rumania faced even more serious problems, sandwiched as it was between the Soviet Union and Hungary, both of whom coveted parts of its territory. The dissolution of the Little Entente and the fall of Czechoslovakia left Rumania in a very precarious position.

  In the Balkans, Hungary and Bulgaria, which sought to expand and reclaim their alleged "lost lands," erected few, if any, significant fortifications. Yugoslavia, Rumania, Greece, and Turkey, on the other hand, set up or planned major defensive barriers in order to safeguard their existing borders and ensure their neutrality.

  MAJOR FORTIFICATION