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General information on Fressinea
Geographical coordinates of Fressinea: 7°07' 03 '' E - 44°03' 45 '' NR in system WGS84.
On this chart, North of the Maritime Alps, important fortifications CORF are represented by black spots: Rimplas (artillery); Fressinea and Valdeblore (Infantry).
Before 1940 the Franco-Italian border passes in the vicinity of Insulated, Saint Saver-on-Tinée and Rimplas, in a zone leading to Nice, by the valley of Tinée, then that of the VAr. Italian infiltrations being to fear, the CORF then studies, since 1927, the operational startup of a powerful strengthened stopping.
Other constructions of infantry (casemates, outposts, blockhouse) will then come to be articulated around Rimplas and will form, in 1940, the Under-Sector of Tinée (65eDI).
Manpower in May 1940: 37 men (1 commander [Biancamaria Second lieutenant], 3 Warrant officers and 33 troops of the 84eBAF)
Armament under concrete: 1.JM/AC47; 1.JM
Armoured observatory: 1.GFM
Considering the extraordinary work of restoration carried out by the team animated by Mr. Bianco Henri, it seemed obvious to us to have to present to you, in detail, this little marvel which became the fortification of Fressinea!
The imposing frontage (with contrepente compared to the border) is only one retaining wall of the relatively friable mountain at this place. The chimney imposing height is the tailpipe of the generators; the chimney low, close, evacuates the foul air.
The main door, for men and ammunition, gives access to a narrow gallery. It is armoured, seals, and followed by another tight door making hopper. Under the fire of a FM, the retractable footbridge crosses a ditch “diamond”.
Frontage before restoration.
Gallery of entry
The FM of interior defense are provided with a “bag” of recovery of the empty cases (visible under FM). Here, by spirit of convenience, FM is exposed on a base and is thus not positioned “normally” in its crenel.
The Latrines “with Turkish” are on chemical pits with soda. As these last are blocked with acids, the such urines, a urinal is imperatively to use before passing in the cabins. The tank (in top) is the reserve day labourer of water for the urinal.
Chemical pits also blocking itself because of the acidity of certain papers (newspaper…), a panel recalls that it is necessary to exclusively use the paper provided by the Genius.
Rescue station - Infirmary
In Fressinea there is no infirmary, in violation with the regulations of the Note of September 2, 1933, relating to installations of the buildings of the Department of health.
SHAT. Extract of the note:
- Bed of Model troop lawful: 1
- Board with luggage without hook: 2 meters
- Stool: 1
Here, the rescue Station, at the entry of the latrines, was tiny room to its more simple expression. It is equipped only with one medecine-chest, which is the acceptable minimum!
Room of the commander
The commander sleeps in his PC. The remainder of the crew is placed in two contiguous rooms.
Room for the 3 pennies/officers
2 bunk beds that divide themselves, by bearing, 3 pennies/officers (There is always one of service of them).
Work management of Fortification. Extract of the Note of the 16.12.1933.
Room of the s/officiers:
- Bed of camp 2 stages, 2 places (n°3 Plan of the Note): 1
- Board with luggage without hook: 1 meter
- Rack of weapons: 0,25 meter
- Table with folding back: 1 meter
- Stool: 2
Room of troop
Room with 20 beds used by bearing (because the men of service do not need beds).
Management the Works of Fortification of Nice. Extract of Note:
Room for 20 men. List furniture:
- Bed of casemate (n°2 Plan of the Note) 2 stages, 4 places with hooks carries-fourniment: 5
- Board with luggage without hook carries-fourniment: 7,5 meters
- Rack of weapons: 2,4 meters
- Table with folding back: 6,5 meters
- Stool: 6
The regulations of the DTF of Nice were not followed to the letter because the beds installed finally were not of type “casemate” but “Séré de Rivières”, assembled “feet against the wall”, for lack of sufficient height.
Work management of Fortification. Nice 16.12.1933.
“The construction of the carcass work of the quartering of the Works of FRESSINEA and VALDEBLORE being finished, it is necessary to proceed without delay to the installation of the furnishing of underground quartering (...) One held for FRESSINEA part of gallery of 2 Mr. to place the wash-hand basins. The installation will comprise 3 spaced taps of 0m60 and being able to produce 1 liter at the minute and per tap.”
The wash-hand basins are surmounted by a reserve day labourer of water.
Beside the wash-hand basins, a urinal, judiciously installed there, avoids with the men the way to the latrines located at the entry of the fortification.
Close to the wash-hand basins, free space is reserved for the storage of various bulky materials, of which filters (anti poison gas) of replacement.
Above this space, a ventilation duct “fresh air” is associated with a heat exchanger making it possible to heat the air, to distribute in the fortification, with cooling water of the generators.
December 1933. Management the Works of Fortification of Nice:
“The installation will comprise a sink, a drainer, two tables of 0,70 X 1m. and two stools. In each kitchen [Fressinea and Valdeblore] a furnace for 50 will be installed rationnaires. The call for tender for this supply will have to be prepared under the conditions indicated by the Notification n°3909 of September 19, 1933 of Colonel Directeur, relating to the kitchen range of CAP-MARTIN.”
Overall picture of the kitchen. The cooker, with coal, is imposing because it is also used as boiler for the central heating of the fortification.
The part “boiler” is visible above on the photograph where one sees one of the sheathed white heat insulator pipes, behind the discharge pipe of smoke. The surge tank of the circuit of central heating is located in the radio operator room, above the kitchen (photo below).
For the kitchen, the reserve day labourer of water, is in end of casemate, above the rack to spices.
Back kitchen with the side “plunges”, on the right, and the scheme of work, on the left. The bottom of the kitchen constitutes a projection compared to the frontage of entry of the fortification, which makes it possible to place a FM of defense of the entry. A scale gives access the room transmissions optics and radio operator located above the unit.
The reserve with coal is at the entry of the kitchen. Certain cookers were transformed, before 1940, to function with the gas oil or electricity. It is not the case with Fressinea where the weak energy needs did not give any emergency character to the transformation.
Reserve for vivres
Services of the Genius
On the wall, are quite visible the two green bottles of compressed air of starting of the engines and the reserve day labourer of gas oil of the n°1 group.
Energy needs electric
A document of the 13.11.1930 gives precise indications on the forecasts as regards electric output necessary:
- Lighting: 820 W
- Normal Ventilation: 890 W
- Filtered Ventilation: 2980 W
- Projector: 2300 W (under 110 V) or 1800 W (special malnutrition in 85 V).
That is to say a maximum total of 6990 W. This power was to be obtained by the coupling of a petrol engine of 6,5 kw with another petrol engine of 2,5 kw. A third engine, also of 2,5 kw would be useful in the event of help. However this instruction was based on a note of 16.07.1930 relating to the use of the generators. Another correction of the 16.06.1931 recommended the use of diesel engines; thus the 19.02.1932, Colonel REDON (directing of the material of the Genius) takes again calculations and proposes the installation of two diesel engines of 11,8 kw (1 engine moving, the other in help). It is about what was installed in Fressinéa.
The first engine was started the 23.07.1935 (with 5:00 of the morning!) and the second 22.10.1935.
Characteristics of the groups
- Diesel engine SMIM 2 SR 14 (n° 547 and 548)
-4 time, 2 cylinders on line
- dimensions: 140 mm (boring) - 180 mm (race) are 2x2771 Cm3 of cubic capacity
- Rotational frequency: 750 tr/min
- Nominal Nominal output: 17,7 kw (24 CV)
- Effective Power: 15,5 kw (21 CV)
- Consumption: 50 liters/day
- Standard Alternator SW SAT 36-19 (n° 8124 and 8126)
- Apparent Power: 14,3 kw
- Active Power: 10 kw
- cos phi: 0,7
- Running provided: three-phase current 220 V - 50 Hz
Starting of the engines, with the compressed air
A characteristic of the engines of company SMIM is to have a compressed-air starting. A pipe leads this air of the bottles to the cylinder head where a special valve and a tap are which makes it possible to send it in one of the cylinders. It is during the phase of relaxation of the thermodynamic cycle that the air is sent reducing the piston. At the end of some towers the phase of compression is enough to ignite the gas oil and the engine starts. One stops the air inlet then.
While the engine turns an astute system makes it possible to recover part of the air during compression and to send it in the bottles which are reloaded.
A whole of piping and valves carry out of the bottles and the starting refuelling line of the engine (see below).
Cooling of the engines
First mode of cooling
The engines are cooled by the water of a cistern of 5000 liters. When this water warms up a little too much, a ventilation “foul air”, extracts the hot air released above the cistern (260 m3/h).
Anecdote: in 1940 the electrical engineer chief had installed his bed between the wall and the cistern (Testimony collected by Mr. Henri Bianco chair association of the “friends of the Maginot work of Frassinéa”).
Second mode of cooling
Two heat exchangers, supplied with the water of the generators, cool this water by heating the fresh air brewed in the fortification.
One of these exchangers is in the factory and the heated air is propelled on the level of the vault, close to the water cistern, where it is extracted by ventilation “foul air”. The other exchanger is close to the wash-hand basins.
Heat exchanger of the factory.
Reserve gas oil and… workshop of the Genius
In this room are côtoient the general gas oil reserves, those of engine oil and… the workshop for emergency repairs, with all that the latter comprises like fire hazards. The gas oil is not very flammable but a door firebreak would have however been the welcome!
General reserve with gas oil.
General water reserves
The water supply, of fortifications CORF, often requires large work of collectings of distant sources. Fressinea is almost built around a source collected in the content of the room where a walled basin, of 500 liters, was built and from where share a pipe which feeds the general reserves.
This source outputs between 0,5 l/s (in summer) and 2 l/s (in winter), putting the crew largely safe from the shortage. Moreover, in Fressinea, the ration day labourer out of water is in the regular manner of 11 liters per man, against 8 liters in the majority of the other fortifications.
Through this grid, located close to the wash-hand basin, one can see running spring water.
The reserves are elevated compared to the remainder of the fortification so that the food of the water points is done by simple gravity.
In front of the general reserves, two small tanks are used one as decanter (before storage) and the other of carbochlorator to return the drinking water (daily consumption).
Together cisterns of the work
- General Reserve: 6600 L. (room of the reserves)
- Auxiliary Reserve: 3300 L. (room of the reserves)
- Tank of control: 220 L. (room of the reserves)
- Tank of daily consumption: 440 L. (room of the reserves)
- Kitchen: 600 L. (in the kitchen)
- Wash-hand basins: 90 L. (above the wash-hand basins)
- Cooling of the weapons: 70 L. (2 mobile tanks of 35 L. in the block of shooting)
- Cooling of the engines: 5000 L. (in the factory) Note:: the presence of the source makes it possible the various tanks to have a reduced capacity, compared to those of other of the same fortifications importance.
Telephone centre (CT, close to the PC) ensures the communications inside the fortification and with the external troops.
Towards room TSF, above the kitchen.
Room TSF with radio operator material and site (walled) for optical transmissions directed towards Rimplas.
We have only little information on the material of optical transmissions installed in the Alps. It resembled that used by the navy (between ships) and was to be replaced by more powerful cases with infra-red transmission (“copy” of what was done then in the Italian fortification).
GR. Group driving back (“fresh air”)
It is a whole of sheaths, ventilators, filters, valves, which takes the surrounding air and distributes it in all the fortification. It is locatable by 3 colors:
- Green: air coming directly from outside (respirable or gauze)
- Red: respirable air
- White: by-pass enters the two circuits
One notices, on this diagram drawn from the official documents, that Fressinea has 2 air intake, one by bell armor-plated (close to the GFM) and the other by grid of frontage (at the bottom of the kitchen). In the majority of other fortifications CORF the air intake is done either by bell or by frontage and the second intake air is even quartering inside, thus making it possible to use an already pure air or to recycle.
On this photograph of the room of ventilation/neutralization one locates the air flow (in top), the filters of neutralization of poison gases (in the center), the departure of the fresh air (in bottom). The “by-pass” is vertical, right before the first of the two filters; it makes it possible to use the powerful ventilator “air gauze” without passing by the filters, when there is no attack by gas.
By a whole of valves and ventilators, according to the needs, the air coming from outside can be filtered or not then driven back in the casemates with more or less large flow. Photograph: ventilator of 4,4kW.
Another sight of the room of neutralization.
GA. Group candidate (“foul air”)
It is a whole of sheaths which extracts the foul air coming from the WC, the factory, the general water reserve, the coal bunker and the kitchen. It is locatable with its yellow color in the fortifications whose painting is of origin (In the others, often only the collars are yellow).
An extractor (GA) of 150 W, located in the factory, expels the air, close to the entry.
One notices, on this diagram drawn from the official documents, that piping coming from the kitchen and the coal bunker “was curiously forgotten”!
It is noticed, as, as the extraction is very important on the level of the cistern with cooling of the engines [Water] (260m3/h). Indeed, in Fressinea there is no aerorefroidissor (mechanical system of heat exchange between the water of the engines and outside). It is ventilation “foul air” which plays this part by extracting the hot air released above the cistern.
Zones isolated by tight doors
Direction of the Engineering services of Nice: (...) The doors of closing of the casemates under rock of quartering will be out of sheet and angles and not out of wood. These doors should be provided with no waterproofing system. On the contrary, of the openings for the exit of the foul air must be bored in the lower panel of the door (...)
However, whereas the majority of the doors must be openwork to let pass the foul air, so that quartering is completely isolated from the sources being able to pollute its atmosphere (outside, shootings of the active casemate, cooks), it is necessary that certain doors are tight. The genius envisaged 4 of them:
(...) The only not armor-plated tight doors whose construction falls on the local service, are the doors indicated below. The project of these doors is to be established according to the directives contained in the letter n° 284/S of the 10.07.31 of the Service of the Materials of the Fortification to which the 2 n°575-1386 plans are joined and 576-1386. In addition, of the sketches of execution of tight doors intended to close bays of 0m80 X 1m95 were studied by Chefferie of STRASBOURG. These sketches already were addressed to Chefferie Work of Nice. (...)
Copy of a sketch.
Doors tight envisaged [and installed] in Fressinea:
-1 door with the foot of the well of access to the GFM
-1 door at the entry of the active casemate
-1 door at the entry of the kitchen
-1 door at the entry of the work forming hopper with the armor-plated door.
Case of the active casemate
Strange! Between quartering and the casemate there activates is not that a tight door and not a hopper (2 successive tight doors to prevent that the entry in the casemate does not depressurize it). Was it prohibits to enter during the shootings or, then, at this time, all the work it with same pressure was? We did not find official documents on this subject but… a trace of local protection of the sheaths of the gallery, making think that the second door of the hopper had indeed been considered.
Entry of the PC.
Office of the PC.
Work management of Fortification. Extract of the Note of the 16.12.1933.
Room of the commander:
- Bed of Model troop lawful: 1
- Board with luggage without hook: 1 meter
- Stool: 1
- Convenient (to be reserved): 1
- Washstand (to be reserved): 1
Bell of observation GFM constituting block 2.
One reaches the foot of the GFM by a scale, then at the observation post of the GFM, by another scale.
Racks with ammunition for the FM of the GFM.
Main door seals block 2. In the GFM, the épiscopes (apparatuses of observation) were replaced by apparatuses provided with video cameras and were connected to a screen located here (thus quite visible for the visitors). It is about a device studied by Bernard Cima, proposed with the team of Fressinea and adoptee.
M1. Reserve for ammunition
Exposure of various ammunition.
The protective grille of the crenels was withdrawn by the Management of the Equipment (security issue) and the ditch diamond was filled.
AC47 out of battery.
Erased AC47, replaced by a JM.
The projector was undoubtedly never installed and its crenel was walled. The projector envisaged had as a role to light a DMP arranged to make jump the road coming from Saint Saver-on-Tinée.
Entry side quartering.
Entry side casemate.
The pollutant gases produced by the shootings must be quickly directed towards outside. This is why not only the casemate is isolated from the remainder of the fortification by a tight door but, moreover, it is put in overpressure (+10Pa for the casemates with JM and AC47). And as the weapons are on tight kneecaps, thanks to this overpressure the pollutant gases which they produce are expelled outside the fortification, by the gun of the weapons, with each opening of cylinder head.
Reserve for grenades and ammunition of 47mm.
Case defense of the ditch diamond.
Thank you in Nathalie Cheesemonger (born in 1973, aggregate of mathematics), for his assistance. It is it which established us the formulas making it possible the legends to follow the plan 3D, during its rotation.