Several successive research campaigns were conducted, a first in 1968 with French resources, another enJuly 1969.
Both were conducted under the authority of the maritime prefect, Admiral de Scitivaux
This is to describe the 1968 campaign.
This 1968 campaign, baptized operation " Reminer " (Research Minerve) was carried out with the following means:
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the resources of the hydrographic dredging mission, i.e. the 810-ton La Recherche hydrographic vessel (formerly Guyana) equipped with an EILAC sounder, and precise location resources thanks to to the radio system Trident ;
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the resources of the Bathyscaphe Group, that is to say the Marcel Le Bihan, a former 800-ton German aviation tender equipped with a 13-ton crane and the 65-ton Archimedes bathyscaphe.
The entire operation was led by CV HOUOT, commander of the bathyscaphe group with IHC.2 PASQUAY, head of the hydrographic dredging mission, under the high authority of Admiral , maritime prefect of the 3rd Region.
This campaign took place in two phases. Initially La Recherche carried out systematic soundings in Sectors 65 and 66 and their immediate surroundings to the south and east. In this area the bottoms are 2,000 to 2,500 meters and are apparently quite flat. The area north of Sector 65, on the other hand, had to be neglected, because it is on the slope of the continental shelf, where the bottoms are extremely tormented, with cliffs and underwater canyons which in particular form the shores_cc781905-5cde -3194-bb3b-136bad5cf58d_east and south of the Banc des Blauquières.
There were initially uncertainties about the location of the searches:
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At the time of this loss of radio contact. the " Atlantic " located the submarine in a position outside Sector T.65 and in its southeast (position B on the map).
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During the searches prior to 1° février, ships had seen a fairly large spot of hydrocarbons north of Sector 65. This spot, according to the witnesses (first masters of tugs of the direction of the port of Toulon), seemed to be produced by gas oil with a characteristic odor rising from the bottom in the form of large bubbles. (position C of the map).
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The location, which could be deduced from the seismological recordings, placed the center of the uncertainty zone at point A of map n" 1, that is to say very slightly in the east of Sector T.65.
This campaign took place in two phases. Initially La Recherche carried out systematic soundings in Sectors 65 and 66 and their immediate surroundings to the south and east. In this area the bottoms are 2,000 to 2,500 meters and are apparently quite flat. The area north of Sector 65, on the other hand, had to be neglected because it is on the slope of the continental shelf, where the bottoms are extremely tormented, with cliffs and submarine canyons which form in particular the eastern and southern edges. from the bench of Blauquières.
Operation REMINER
Extract from Revue maritime n° 264 (pages 431-443)
Commander Georges Houot
Admiral Philippe de Scivaux
There were initially uncertainties about the location of the searches:
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At the time of this loss of radio contact. the " Atlantic " located the submarine in a position outside Sector T.65 and in its southeast (position B on the map).
-
During the searches prior to 1° février, ships had seen a fairly large spot of hydrocarbons north of Sector 65. This spot, according to the witnesses (first masters of tugs of the direction of the port of Toulon), seemed to be produced by gas oil with a characteristic odor rising from the bottom in the form of large bubbles. (position C of the map).
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The location, deduced from seismological recordings, placed the center of the uncertainty zone at point A of map n" 1, i.e. very slightly to the east of Sector T.65.
Research on oil spills
A first series of research attempted to determine where the origin of the oil rising could be located. This did nothing, because it should have been carried out under conditions similar to the weather of January 27, by strong mistral, and its effects would then have been impossible to observe._cc781905-5cde-3194- bb3b-136bad5cf58d_
Preliminary search for echoes that may be those of a wreck
A search by sounder on such a bottom could therefore not reveal the presence of any wreckage. The zone that appears on map n° 2 was explored by lines of probes spaced 50 meters, 100 meters, 200 meters according to the sectors (sector at 1/5,000, 1/10,000, 1/20,000). The normal search is that which is made with the spacing of 100 meters, the spacing of 50 meters having been used for comparison in a restricted zone. The 200 meter gauge was used in a larger area to cover the point given by the aircraft.
Throughout this zone, the bottom is generally regular. It is largely covered by a sedimentary layer with slight uneven relief (rocks, small cliffs). The quality of this exploration was strictly linked to the characteristics of the sounder used. This one (a German ELAC sounder on 15 kilocycles with a total aperture of 24 degrees) theoretically makes it possible to detect obstructions protruding one meter from the bottom. In practice, this figure had to be reassessed to four or five meters, because of the slopes, slight valleys, and the fact that the sounder, at each echo, covers on the bottom a circular sector having a radius of the order of 120 meters. Under these conditions, La Recherche found about fifteen echoes that could look like wreckage. She then had to work on classifying these echoes by passing over their position on different routes, thanks to the precision of 10 meters given by the Trident navigation system. The result of this work was to classify two echoes as certainly corresponding to an obstruction (the echoes which are carried at positions 01 and 02 of map n' 2), certain others being classified as only probable, the others being eliminated.
This classification operation is perhaps at the origin of certain press articles which claimed that the Minerve had been found. However, such a conclusion could only be announced after having formally identified by sight the obstructions thus located. This is indeed what the sequence of operations was to demonstrate.
Let us add that to obtain such precision on the measurement of the bottom, it was necessary to have fine weather. August 1968 was a particularly unfavorable month. During the day, there was a strong mistral. The Recherche was to set sail at night as soon as the wind died down. A number of profiles made in sea conditions estimated as “ limite ” had to be resumed later.
Archimedes bathyscaphe dives
It was only after this preliminary work that the second time could begin, that of the visual identification carried out by the bathyscaphe Archimedes. The latter carried out seven investigations, at the points marked 01, 02, 03, 09, 010, 014. 017 on map n° 2. These investigations were carried out as follows:
a) — Research takes the Marcel Le Bihan close to the echo to be surveyed, then places this vessel in relation to itself and uses the information in azimuth-distance of the Archimedes given by the Marcel Le Bihan. For the last two dives, this rather cumbersome method interrupting the sounding work, a receiver Trident taken from another MHD building was installed on the Marcel Le Bihan, stopping its work for a few days.
Bathyscaphe Archimedes
b) — The Archimedes, ready to dive, is towed by the Marcel Le Bihan, in such a position that, given a slight drift, it can arrive a few hundred meters from the echo to be explored: this in order to prevent the bathyscaphe from landing on the wreck.
c) — The Archimedes, being in contact with the Marcel Le Bihan by ultrasonic phony, is positioned by also ultrasonic means. The Marcel Le Bihan gives the Archimedes the azimuth and the distance of the echo. The Archimedes then moves towards the indicated point, reporting his movements, and placing himself again if necessary.
This method gives a total uncertainty of 300 meters on the positioning of the Archimedes. However, it led to excellent results, because this error is consistent with the Archimedes' own means of detection (a Strazza panoramic sonar). The latter was therefore able to come within sight of the wrecks, despite the very limited visibility of the Archimedes porthole and the fact that in the total darkness of these depths, its searchlights yet very powerful allow you to see no more than ten meters. Several times besides the guidance was useless, the Archimedes having echo of the obstruction before arriving at the bottom.
1st dive — September 17 — Oscar 2 — depth 2300 meters
This is then the most spectacular part of the operation. The first dive of the Archimedes takes place at point 02 on September 17 at a depth of 2,300 meters. At 80 meters from the bottom he obtained an echo at 600 yards on the Strazza sonar. He slowly approaches this echo and sees it split, one echo appearing to be 90 meters long, the other 30 meters. It also detects many small echoes over a hundred meters from the two main echoes. About ten meters from the smallest echo, the passengers of the Archimedes see through the porthole a pile of twisted angles and sheets. Between the two wrecks the ground is strewn with shapeless metal debris. Close to the most important wreck, the Archimedes sees an almost vertical wall which it docks and on which it slides and scrapes, this hull being covered with a very dense fauna. He then distinguishes a porthole then two others and what seems to be a propeller guard. He then realizes that this wreck is not that of the Minerve, but that, old, of an unknown building. On returning to the surface, there were traces of scraping on the Plexiglas port side of the headlamp cantilever, with visible streaks of probably white paint.
2nd dive — September 20 — Oscar 1 — depth 250 meters
On September 20, the Archimedes dives at point 01. He gets an echo at 400 yards while he is still 150 meters from the bottom. He headed for this echo without being led by the Marcel Le Bihan. About a hundred meters from the echo, the wreckage appears perfectly on the sonar screen. It is 60 meters long. Approaching, the Archimedes sees a three-bladed propeller and a freighter stern. He goes around the wreckage which is covered with unidentified animalcules. He then sees ropes and steel cables hanging along the edge as if they came from davits. He also sees objects corresponding to small neighboring echoes, a metal cube 2 meters on a side which could be a small footbridge and a metal chest. So it's still a disappointment, echo number 01 is not Minerva.
This disappointment was repeated with the other echoes, which turn out to be nothing but accidents in the background, cethat Commander Houot calls the mini-relief of this abyssal plain, small cliffs or rocky masses emerging from the sedimentary layer. During these dives, objects of small dimensions are detected and seen.
We can extract from the report of the commander of the group of bathyscaphes the account of other dives. Less easy than the ones we have discussed so far, because the objects sought were more difficult to identify.
4th dive — October 8 — Oscar 9 — depth 2350 meters
“The Marcel Le Bilan leaves the Archimède freedom to explore two close echoes that he pointed out to him when he arrived on the bottom. The first corresponds to the fins of a rocket planted in the ground, the second is that of an isolated rock mass 3 meters high and 3 meters in diameter, half sunk in the sediment as if it had dug a pit. (This impression of filth led Commander Houot to wonder if it was not a meteorite).
A positioning carried out near this rock tells the Archimedes that it is in the 115 and 1,000 meters from Oscar 9. Halfway through a good metallic echo encourages it to change its course towards the 240. A second rocket is spotted. The Archimedes then sailed at 350 towards Oscar 9 and, considering that it had traveled the prescribed path, requested positioning again. Oscar 9 is reported to him in the 035 at 700 meters. This trip having been made without discovering anything other than very small variations in slope, the Archimedes explore a weak echo of relief of a hundred meters
in length and located in the 150 to 300 meters of the estimated position of Oscar 9, then continues in the direction of the isolated rock near which it is again positioned. Marcel Le Bilan finds him in the 090 at 1,000 meters from Oscar 9, which confirms the esteem. After 600 meters of course and without having discovered anything ofnew, heis obliged to interrupt the dive, the batteries being discharged. »
5th dive - October 11 - Oscar 9
“ Believing that the western region of echo Oscar 9 was not explored during the dive of October 8, I send the Archimedes again on this echo. (Commander Houot is speaking).
A first positioning places the bathyscaphe 200 meters from Oscar 9. A second places it shortly after practically on the position of Oscar 9. The Archimedes during this short movement observed only a slight slope of 5 to 10 ° which seems oriented at 160. The Marcel Le Bihan, then gives him freedom of maneuver as it was agreed the west of Oscar 9. Heading south-west then north-west he discovers 1,000 meters further the echo of a sedimentary cliff oriented at 290 and 500 meters long. He is positioned and is in the 260 and 1,000 meters from Oscar 9. From there he heads successively to the northwest then or southeast in order to return to Oscar 9. It is by rallying this point by the north -west that appears on the sonar scope an echo of relief 100 meters long oriented at 250. The low and gradual slope of this relief did not allow at the beginning or at the end of the dive to appreciate its height_cc781905- 5cde-3194-bb3b-136bad5cf58d_”.
6th dive — October 15 - Oscar 17
The Archimedes arrived on the bottom is on a hill (slope 81, it is done position. He was sent to Oscar 17, from which he was 500 meters away in the 307. The Archimedes on its way to Oscar 17 encountered many mounds (sonar echoes, diffuse and fuzzy). The slope is such that it happens that the front of the traveling crane gets stuck in the mud. A metallic echo in k 10 at 400 yards confuses the Archimedes. This echo is a canister of the 200 liter oil barrel type.
Failure therefore, the wreckage of the Minerve was not found without being able to ensure that it was not in the explored area.
The searches were then abandoned, they reprendront in 1969 with more efficient equipment.