gipuzkoakultura.net
gipuzkoakultura.net
viernes 22 noviembre 2024
Noo sooner had the Third Carlist War had come to an end than the military authorities began to reorganise the defence of the French border, the city of San Sebastian and the port of Pasaia [Pasajes]. They knew the works would also ensure their military domination of the territory in the event of a fresh Carlist uprising.
Various military councils and committees were formed between 1876 and 1884 to study these and other questions. In 1876 the Engineering Corps formed a committee to study defence of the border, and in 1877 it decided to build forts on the hills of San Marcos, Txoritokieta and Arkale in Gipuzkoa. The preliminary design was entrusted to the Engineering Command of San Sebastian. The result of its work, however, did not please higher authorities. Juan Roca was commissioned to design a new project for San Marcos, which was finally approved in 1879.
In the meantime, after long debates among senior strategists, Colonel Antonio Rojí and Lieutenant Colonel Francisco Roldán were commissioned in 1884 and 1885 to verify the study of the defence of the Pyrenees in Gipuzkoa. The result of their work was the design of a complex set of fortifications formed by three lines of defence, which in practise was simplified to eight forts1. Five formed an arc around Irun (Guadalupe, St. Henry's, Arkale, Belitz, Erlaitz and St. Martial's) and another two (St. Mark's and Txoritokieta), further back, could be used to defend San Sebastian and the port of Pasaia. Of all of these, the only ones to be built were the forts of St. Mark (1888), Txoritokieta (1890) and Guadalupe (1900). Work began on the Erlaitz fort, but was halted during the initial phase in 1892.
The structure of the forts of the entrenched camp of Oiartzun is very similar to that of the first period of the Séré de Rivières system. In simple terms, they could be described as polygonal fortifications, with a fosse flanked by double caponiers. Access to the fort was by means of a drawbridge; internal communications ran partially underground and the guns were located outdoors, protected by a parapet and traverses or by casemates projecting out from the rest of the fortification. Most of the installations (casemates, barracks and powder magazines) were built in masonry and unreinforced concrete around 1-2 m thick, covered in various metres of compacted earth, which theoretically provided protection from enemy shells.
The building process was similar for all the forts. First a preliminary project was drawn up, followed by projects for the accessory works, normally three in number: the access road to the position, water channels and a provisional camp. Finally the definitive project was drawn up.
Forts were generally built on sites of difficult access, at some distance from the nearest town, and the building of an access road was therefore of great importance. In the case of Erlaitz it was sufficient simply to adapt the existing local road network; in Guadalupe a short branch road, 200 m in length linked the fort to the nearby road to Hondarribia. St. Mark's, however, needed greater attention, since it required the building of a military road 6.6 kilometres in length to link the fort to the main road to France. In Txoritokieta a 1.3 kilometre branch road had to be built from the St. Mark's road.
Water was raised mechanically during the building work and stored in a tank. Once construction was complete, any rainwater that fell in the fort could be stored in the cisterns, with the earthen blindages acting as filters.
The provisional camps were composed of barrack huts which housed offices, stores, the kitchen, latrines, a guard post and a number of workshops (for forging, carpentry, quarrying), etc.
The preliminary projects were detailed enough to allow work to begin before the definitive projects were complete. Indeed, the final project for St. Mark's Fort (by Luis Nieva) was not completed until 1888, a few days after the fort was commissioned. The provisional and preliminary projects by Pedro Lorente (1878), Juan Roca (1879 and 1881) and José Brandis (1884) - rejected because of different deficiencies or changes in strategy plans - were therefore of great importance.
At the Erlaitz Fort too, the initial work was based on the preliminary project by Rojí and Roldán, but it was halted because the project presented by Luis Nieva proved very onerous and did not take into account the advances made in artillery since approval of the preliminary project.
The work carried out at this fort - which was limited to preliminary excavation- offers a fine illustration of the building technique employed. Many of the facilities (barracks, stores, etc.) had to be built underground. It was therefore necessary to dig pits (for the rooms) and trenches (for communication purposes). The buttresses were made of masonry and the vaults of unreinforced concrete, covered with various layers of masonry, dry stone, earth, etc.
The batteries could be protected by casemates or left open to the elements. Casemates consisted of vaulted buildings projecting from half-way up the fortification. The gun embrasures were situated in the masking walls (or sidewalls of the vaults). To limit the impact of shells, the building was covered in earth (between 6 and 14 metres thick) into which gun emplacements were also set.
The casemated battery at St. Mark's Fort consisted of a roughly U-shaped building in unreinforced concrete, around a central courtyard closed off by the barracks at the gorge (the least exposed part of the fortification). It is two storeys high. The upper storey is formed by fifteen vaulted casemates (14 x 5 m) linked by arches between the buttresses, 4 metres in span. There are nineteen gun emplacements In the masking walls, although eight of them are blocked off by the external blindage of earth, originally allowing a total of seven 15 cm cannons mounted on a low carriage. Another four cannon were installed in gun emplacements in the two gorge casemates. The lower floor has eight rooms2.
In the Guadalupe Fort, the casemated battery has a rectangular floor-plan. It consists of three storeys. The lowest (protruding out from the rest) forms a continuation of the scarp gallery. The intermediary floor, with nine vaults, was used as a barracks and could house 276 men. At the eastern end an additional vault housed the ammunition distribution store. The upper floor incorporates the casemated battery itself, formed by ten vaults with gun emplacements at either end3. A masque of earth, separated from the casemates by a narrow courtyard, stood before the barracks and batteries to the South East, into which tunnel-embrasures could be built so that the cannon could be fired from the casemated battery.
The open-air batteries are barbettes (parapets without gun emplacements) arranged according to a general pattern consisting of a parapet 8-10 m thick ending in a bank leading down to the fosse. For its interior fortification the parapet has a covering wall whose height varies (1.4 - 1.8 m) depending on the type of artillery installed. Where necessary there are concave semi-cylinders in the parapet, to aid gun movements.
Platforms were built on the fighting rampart (or adarve) with firing positions, protected at the front by the parapet and at the sides by traverses. Inside the latter, there was sometimes a narrow passage, to allow troops to cross from one side to the other. From it, it was possible to access the ammunition stores for each gun.
At a lower level there was generally a communication rampart or service path which formed part of the fort's communications network. This was joined to the fighting rampart by ramps and there were vaults opening onto it which had traverses to shelter those serving the guns. In peacetime these could be used to house mobile guns. This feature is only found in some sections of the Guadalupe Fort.
Special care was taken over all aspects related to ammunition. Generally there were one or more powder magazines, which in some cases (Txoritokieta and the project for Erlaitz) had a narrow passageway running around the perimeter into which the air ducts and windows opened. The windows were sealed with glass on the magazine side, to prevent any sparks flying out of the lamp.
The powder magazines had a concrete floor with a false floor at a certain height above it. A chamber of air between the two helped prevent the powder from getting damp. The walls of the magazines were lined with wood from the floor to the bottom of the vaulting.
The forts contained various stores (for shells, artillery tackle, provisions, firewood, etc.) and filling rooms, where the shells were filled with gunpowder or other more powerful explosives. Near the ammunition dumps there were lifts to carry the gunpowder and filled shells to the magazine for each piece.
The Guadalupe fort was garrisoned4 by 500 infantry and 100 artillery men , while St. Mark's Fort had 200 infantry and 50 artillerymen and Txoritokieta had about 60 men (although the preliminary project mentioned up to 200). Nonetheless all the forts had special areas which could be used to add up to house up to 50% more men.
The main purpose of the artillery was long-distance action, while closer range defence (rebutting any attempt to take the fort by enemy infantry), was the work of the riflemen. The riflemen had a covered way consisting of a narrow esplanade bordered by a firing parapet, supported by the glacis. As in modern fortifications, this made it possible to fire on any point in the area around the fort5.
At St. Mark's there was a second rifle line, consisting of a parapet on the upper blindages of the gorge barracks and the casemated battery. At Txoritokieta, where the fort was located on a steep mountainside, it was considered sufficient to have eight rifle trenches about fifty metres in length at distances of between 12 and 200 metres from the counter-scarp.
The fortifications were completely surrounded by a fosse, with a width of between 6 and 8 metres, and different gradients and depths in different sections. The fosse was bordered by dissymmetric scarps and counter-scarps (the counter-scarp was higher than the scarp) to prevent enfilade enemy fire. They were covered in polygonal ashlar stone or masonry.
At the Guadalupe Fort, the covering wall of the scarp is replaced by a simple slope resting on a low wall 1.4 metres in height on which there was a 3.5-metre metal railing. The purpose of this arrangement was to minimise the impact of torpedo grenades, since the railing fended off the new shells fairly well. The rest of the scarp was occupied by a scarp gallery or set of linking vaults at right angles to the fosse, in whose masking wall there were various embrasures allowing defenders to shoot transversally towards the fosse.
The fosse was mainly defended by the flanking batteries situated at the angles. The double caponiers defended two sections of fosse and the caponiers one. They had embrasures and machicolations for rifle fire and gun emplacements for machine guns or small-bore cannons (5.7 cm) capable of rapid fire (30 rounds per minute), which could fire canisters of shrapnel capable of annihilating any enemy contingent that had managed to reach the fosse.
The infantry occupying the covered way could go down into the fosse using the counter-scarp stairs situated close to some of the flanking batteries and reach the batteries through sally ports. These gates were fitted with drawbridges or retractable bridges on the refosete. The refosete was a small fosse standing before the caponiers and double caponiers. Its purpose was to prevent the enemy reaching gun emplacements and embrasures, while at the same time serving as a receptacle to prevent the emplacements and embrasures being buried under falling debris.
The Guadalupe fosse is flanked by two caponiers and three double caponiers: In the case of St. Mark's Fort there is one caponier and two double caponiers, while the Txoritokieta fort has no proper flanking battery; the fosse is smaller and its walls form a bank (3 metres across at the bottom and 4 at the top).
The three forts have external auxiliary batteries. This type of fortification was intended to be occupied in times of war by the army operating in the entrenched camp (about 40,000 soldiers). The main purpose of the auxiliary batteries was to complement the artillery of the forts and to defend the surrounding area, which might lie outside the range of the internal artillery. They consisted of a low parapet (suitable for field guns) and for that reason they often had covering trenches for the soldiers manning the guns. The project for the Guadalupe Fort envisaged the building of four auxiliary batteries, but only one (the Calvary battery) was eventually constructed. St. Mark's has two (the Barrack Hut Battery and the Kutarro Battery) and Txoritokieta has one. In general they had a small area for housing troops and ammunition.
The ordnance of these forts varied down the years. St. Mark's Fort initially had fifteen-centimetre hooped iron cannon and 21-centimetre iron mortars. These guns were replaced in 1890 by 154-centimetre Tubed Iron Cannon (TICs) and by 21-centimetre bronze mortars. The Txoritokieta Fort was initially gunned by six fifteen-centimetre TICs.
During the unrest in Cuba and the Spanish American War of 1898, some of the guns from the two forts were removed. They were subsequently fitted out with guns on wheeled carriages, except for the guns used for coastal defence, which kept their fixed bases.The Txoritokieta Fort was the first to be decommissioned and the army attempted to sell it in 1953. The others two were taken out of active service6 in the 1970s, and eventually became municipal property.
| Fort | Alt. | Maximum | Safety contingent | Garrison | Observations |
|---|---|---|---|---|---|
| San Mark | 271 | 27 | 19 | 250 | Finished in 1888 |
| Txoritokieta | 310 | 7 | 6 | 60 | Finished in 1890 |
| Guadalupe | 210 | 60 | 35 | 600 | Finished in 1900 |
| Erlaitz | 508 | 20 | 16 | 311 | Halted in 1892 |
| Belitz | 500 | 20 | 11 | 300 | Preliminary project |
| Arkale | 268 | 38 | 14 | 200 | Preliminary project |
| St. Henry | 547 | 6 | 6 | 60 | Preliminary project (?) |
| San Martial | 218 | 39 | 12 | 200 | Preliminary project |
| Total | 217 | 119 | 1.981 |
*.- This figure does not take into account the artillery that could be housed in the auxiliary batteries or the small-bore artillery and machine guns for defending the fosses or the next defence post. Go to the asterisc
2.- The first two as one entered the fort were used as Corps de Garde: one for officials and the other for the regular troops. The third room housed the access to the mortar battery (up a ramp and stairs), followed by the stores where gunpowder, shells (both with their respective lifts), artillery tackle and victuals were kept. The eighth room was occupied by the officers' quarters. Go to the link of note 2
3.- It has five gun emplacements overlooking the sea (the rest are covered by the earthen blindage) and to the south there is a a curved battery for three mortars and three reserve gun emplacements. A 60-centimetre track was provided from the lift to facilitate transport of ammunition. Go to the link of note 3
4.- The barracks were only designed to house a third of the garrison, as it was estimated that at any given time during fighting, one third would be manning the artillery, another third would be involved with the ammunition and only one third would be resting. During peacetime the small detachment stationed to guard and upkeep the fortification fitted easily in the barracks. The officers and the governor of the fort had quarters of their own. Go to the link of note 4
5.- In order to keep the glacis clear and ensure that there were no elements behind which the enemy could take cover, up to three special areas were defined. For each one, there were a set of rules limiting building and even the planting of trees around the fort. Go to the link of note 5
6.- On occasions they were used as military prisons. They only saw action during the opening months of the Civil War in 1936. Go to the link of note 6
