Serrada plant

Serrada plant under attack, May 1915

The Serrada plant ( Forte Dosso del Sommo in Italian ) is located about four kilometers south of the municipality of Folgaria at an altitude of 1,670 meters. It belonged to the Austrian fortifications on the border with Italy .

task

The plant should block the road from Val Terragnolo from the south and the Passo Coe with the road from Tonezza to the south-west. A breakthrough through the first would have led directly to Rovereto , through the second to Calliano in the Adige Valley . This would have rolled up the Adige Valley front from the back.

Building description

Started in 1911, the construction work was completed on September 12, 1914 by Captain Karl von Bedekovic. The planning had been carried out by Captain R. Mayer in the staff of genius .

It was the last of the fortress bar to be built and the most modern on the Italian front. Similar to the other works of the Austro-Hungarian Army in the groups of works Folgaria and Lavarone and in contrast to the older works of the so-called Vogl period, they did not build a compact complex, but rather the guns on two battery blocks (the rear of which also served to accommodate) listed separately (dissected). This reduced the hit effect when bombarded. The two blocks were laterally offset and staggered one behind the other. They were connected to each other by a concrete postern (this did not withstand the bombardment and was replaced from June 1915 by a postern driven through the rock). The front machine-gun block and the front trenches were connected to the front battery block by a tunnel. The facility was surrounded on three sides by a trench up to seven meters deep. In this system, the melee system and the front battery block are already about 45 meters apart; that is more than 50 percent of the longitudinal scatter of a heavy steep-slope gun of the time. The ammunition magazines were already placed under cover of the natural rock (i.e. the buildings nestled against the rock on the enemy side) and were connected to the guns by elevators.

The ceiling, between 2.5 and 2.8 meters thick, was reinforced with I-beams above the casemates , but not the postern above ground between the battery and casemate blocks, which led to breakthroughs with a caliber of 28 cm (the reinforced Ceilings could only be penetrated with a caliber of 30.5 cm). The thickness of the I-beams was NP 40 (40 cm high) on the top floor and NP 26 in the false ceilings.

The factory ceiling was covered with galvanized sheet metal and thus protected against the effects of the weather. Sheet metal hoods were also available for the armored turrets as weather protection. However, these could only be used in peacetime. After the mobilization there was only a small sheet metal hood over the openings in the armored dome.

The construction costs were estimated at 1,900,000 crowns and exceeded by 69,000 crowns.

Plan of the Serrada plant

The system in detail

• Trench pranks

The trenches were two-story with two 6-cm casemate cannons M.10 in the basement and two tank casemates with two machine guns each on the upper floor. There were two spotlights with a diameter of 25 cm.

• Front machine gun block

Two fixed MG armored domes each with two Schwarzlose M7 / 12 machine guns . Up to 20 additional infantrymen could be accommodated here, who were to be deployed in prepared positions for close defense outside the block. This complex therefore had a rear exit to the factory roof, which was secured by a small kennel . The walk from the battery block to the moat weir leads through here.

• Front battery pack

Two howitzer tank domes each with a 10 cm tower howitzer THM9 in a depression mount , two fixed machine gun tank domes each with one and two machine guns and a rotating observation tank dome that could be equipped with a machine gun . A headlight with a diameter of 60 cm could be placed on the hood (during the bombardment-free time). Among other things, his job was to illuminate the road to Monte Maggio. The battery block had two floors, the lower one consisting almost exclusively of a connecting passage, into which the postern from the rear casemate / battery block ended, and the underground passage to the machine gun block branched off. Furthermore, in the right part there was the base for the two fixed machine gun domes, an ammunition magazine and a ready room. There was also an abortion in this area .

• Rear battery and casemate block

Two howitzer tank domes each with an M.9 tower howitzer in a depression mount. Each of these domes had a headlight with a diameter of 35 cm. At the ends of the building there were two fixed MG armored domes with two machine guns each, and in the throat defense there was an armored casemate with a 25 cm searchlight and a machine gun to coat the throat . The accommodation and utility areas were also located in this block. The complex consisted of four floors:

• Basement

2 fuel depots

1 genius material depot

1 artillery material depot

1 workshop with depot

1 accumulator room

1 engine room (generator set)

1 fuel depot

1 crew accommodation

1 defensible guard room

1 entrance with kennel

1 Lower area of ​​the larynx with toilet and crypt for six coffins

2 staircases to the ground floor

• ground floor

1 treatment room

1 infirmary

2 food depots

3 crew accommodations

1 kitchen

1 officers' quarters

1 doctor / attendants' room

1 throat case with armored casemate for two machine guns and a toilet

2 staircases

1 ammunition magazine for 10 cm tower howitzers

2 manipulation rooms with ammunition lifts

• First floor

1 crew accommodation with optical signal station for Monte Biaena and Monte Finonchio

1 crew accommodation with optical signaling station to Monte Cornetto and Sommo intermediate plant , switchboard and standby room

8 accommodation rooms for the team

1 throat case with weapon station, toilet and optical signal station

2 staircases

1 ammunition magazine for 10 cm tower howitzers

2 manipulation rooms with ammunition lifts

• Ceiling floor

1 three-part armored dome for three machine guns and a 25 cm searchlight (left)

1 three-part armored dome for four machine guns and a 35 cm searchlight (right)

2 tower howitzers M.9

1 ammunition magazine for the machine guns

1 ammunition magazine for the tower howitzers

1 postern to the upstream fighting stalls with secured exit on the factory roof

2 staircases

The two battery blocks were connected by a concrete postern above ground. The communication between the front battery pack, the machine gun complex and grave pranks was an underground, driven by the rocky transition. After the concrete post between the two battery blocks was destroyed, it was replaced by a 56-meter-long underground passage.

After the experiences that had been made during the bombardment of the Verle and Lusern plants in particular (the constant fire with medium calibers on the access roads had made them impassable), work began on building an underground access post at Serrada, which is 260 meters long , led from the left part of the casemate block to the northwest. Since the plant's ventilation was originally located in the Kehlgraben, from where the explosive gases from the exploding grenades were constantly sucked in, this tunnel is now also used to supply fresh air. Spread over the entire length, 13 caverns were carved out of the rock to provide the crew with safe cover in the event of fire with 30.5 cm shells. The construction of this tunnel lasted from September 2 to November 29, 1915.

crew

Detachments of the Imperial and Royal Landesschützen Regiment “Trient” No. I , the fortress artillery battalion No. 6 from Trient and Chiesa di Lavarone were assigned as standardized war crew ; a total of four officers and 227 men. However, since these units were all on the Eastern Front when the war with Italy broke out, everything that was available was initially used (in total, only the second-rate infantry divisions No. 90-94, 49 artillery batteries and small cavalry forces were available for the entire front to disposal). The artillery crew for all plants therefore consisted of the 2nd company of the fortress artillery battalion No. 1 from Tenna (battalion commander Lieutenant Colonel Ludwig Pengov) and the 1st - 4th company of the fortress artillery battalion No. 8 from Haidenschaft and Wippach ( Battalion Commander Colonel Alfred Langer).

The infantry defense of all works was initially in the hands of a marching battalion of the Imperial and Royal Landesschützen Regiment Innichen No. III . Standschützen were also called up not directly to the factory crew, but for close defense . The artillery command in the works was with the fortress artillery battalion No. 6 (like all operational units, the FstArtBaon No. 6 was initially relocated to the Eastern Front at the beginning of the war).

Fighting

On May 25, 1915, around 4:00 a.m., an Italian 28 cm howitzer from Monte Toraro (1817 m) near Forte Campomolon fired the first shot at the Serrada plant over a distance of about 9.5 kilometers . From May to the end of October 1915, the Italians fired 4,229 shells with a caliber of 28 cm at the movement, which was only moderately damaged with a hit rate of 11.5%. However, from June 9, 1915, the concrete bollard, which was sunk but not underground, between the casemate and the front battery block could no longer withstand the fire. From June 9, 1915, it was partially destroyed by twelve direct hits in a confined space, otherwise there were no breakthroughs. 28 hits fell on the armored parts, with one penetration in the armored armor of tower howitzer No. I. However, this projectile turned out to be a dud . A direct hit on the dome of the tower howitzer No. II only caused a 11 cm deep dent. The rotating observation post was hit on the pre-armored car and failed for four days. The Serrada plant itself fired a total of 26,103 10 cm grenades during the war, more than any other plant in the Folgaria and Lavarone groups .

After the bombardment began, the weather protection hoods of the armored domes were placed a little away from the factory in order to deceive the Italians. In fact, the four tin hoods were shot at for several days until the oversight was noticed.

The attempt to defeat the plant by artillery was not carried out as consistently by the Italians as against the Verle, Lusern and Vezzena plants in the main thrust, since no 30.5 cm howitzers were used. In addition, it was never exposed to an infantry attack.

Between the wars and today's condition

In July 1931, Serrada served as a target for a test shoot by the Italian army, which wanted to gain experience for their new fortress line, the Alpine Wall (Vallo Alpino), which was built from 1932 on the borders with France , Yugoslavia and Austria . In order to simulate the vertical impact of a projectile fired from a distance of 10 km, a 30.5 cm L 17 coastal howitzer was brought into position on an improvised wooden sledge at a distance of only 127 m and thus fired several shots in the directional range of approx. 89.8 ° on the concrete of the front battery wing at the height of the tower howitzer No. II . A number of calculations had previously been carried out in order to reduce the muzzle velocity and, above all, to determine the correct weight of the cargo at around 8 kg. Since the 30.5 cm L 17 coastal howitzer only has a height adjustment range of max. 65 °, the optimum angle of impact of the shells had not been reached during the bombardment - even if the impacts had devastating consequences at this angle. These experiments were therefore used to find out about the optimal angle of incidence. Test explosions were also carried out on armored steel. The high quality of the Austrian construction method was shown once again. As part of these experiments, tests were also carried out on radio links from armored domes between the Sommo and Serrada plants.

Since the bombardment of the Folgaria group was not as severe as that of the Lavarone group ( Lusern and Verle ), the damage was not as serious here either. In the Mussolini era, the steel girders of the reinforcement and the other armored parts were blown from the factory ceilings in order to extract steel scrap, which caused considerable subsequent damage. Nevertheless, in contrast to various neighboring plants, the Serrada plant was relatively little damaged and can be entered.

The Italian civil protection training for rubble search dogs took place (or is still taking place?) At the plant. The plant can be reached from Serrada by cable car to Rifugio Baita Tonda on Martinella (1604 m).

Remarks

1. ↑ not rotatable, with an oval floor plan and two reject openings
2. ↑ set up with loopholes to pass through for defense
3. ↑ Since there was no career group of NCOs in Austria-Hungary, they are counted among the teams.
4. ↑ The State Rifle Regiment I fought from May 9 to 15, 1915 in combat near Smerek, Krywe, Sokolowa wola, Zasadki, Sudkowice and Laszki Zawiadzane and did not arrive in Tyrol until June 12th - see ibid
5. ↑ Rest-Ortner-Ilmig p. 12.
6. ↑ Classification of the war for the spring of 1915 in: “Austria-Hungary's Last War” Volume II, Appendix 14. The planned occupation was still on the Eastern Front, so everything that was somehow tangible was initially taken.
7. ^ Lichem: The history of the Kaiserschützen. P. 208.
8. ↑ There were forces of the standardized crew available, but probably not in full strength, the allocation of other units suggests this.
9. ↑ Wolfgang Joly: Standschützen. P. 520.
10. ↑ Hentzschel p. 113
11. ↑ Hetzschel, Festungskrieg, pp. 111, 113 fu 224–227.
12. ↑ Hetzschel, Festungskrieg, p. 225.
13. ↑ Hetzschel, Festungskrieg, p. 224, an infantry attack is not mentioned anywhere
14. ↑ The event described here comes from: Paolo Pozzato: Il Genio italiano e la fortezza di Serrada , accessed on September 19, 2017.

literature

• Rolf Hentzschel: Austrian mountain fortresses in the First World War. Athesia, Bozen 1999, ISBN 88-8266-019-2 .
• Rolf Hentzschel: Fortress war in the high mountains. Athesia, Bozen 2008, ISBN 978-88-8266-516-6 .
• Erwin Anton Grestenberger: Imperial and Royal fortifications in Tyrol and Carinthia 1860–1918. Verlag Österreich, Vienna 2000, ISBN 3-7046-1558-7 .
• Paolo Pozzato: Il Genio italiano e la fortezza di Serrada in: Museo Storico Italiano della Guerra di Rovereto (ed.): Annali n. 14/15/16 , Rovereto 2009, pp. 91-100.

Web links

Commons : Werk Serrada  - collection of images, videos and audio files

Coordinates: 45 ° 52 ′ 43 ″  N , 11 ° 11 ′ 19 ″  E