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The French approach was quite different. They also understood that to prevent the extinction of the flame it had to be isolate from the water but instead of using the iron carcan as that used by the Germans, Mr. C. Picard will instead use a kind of flared bell.
In 1912 his underwater gas burning torch called the "oxy-Secator" working with an oxyacetylene mixture appears for the first time in France (21).
Figure 6: Sketch the oxy-Secator (21)
As seen in the sketch, the nozzle of the torch was equipped with a bell in which two diametrically opposite small tubes are connected. These supply the compressed air which is designed to remove the water from the bell and the metal area to be cut.
Around its periphery the bell was also equipped with 3 small guides to keep a constant distance between the flame and steel.
To achieve the development of his machine he organizes from 1912 one series of dive but these were unfortunately interrupted because of the war.
Finally, the torch is ready and on June 10, 1917 a new cutting demonstration is organized in a tank in front of some personalities during which a diver managed to cut a steel plate of 400 mm long x 40 mm thick (22).
Unfortunately the literature does not states the time taken to achieve this cut but it seems that the torch worked properly because at the end of the war various "oxy-Secator" are commissioned to assist in the removal of 5750 T English cruiser H.M.S Vindictive that was scuttled on May 10, 1918 to bottle the Ostend Harbor.
Prior to disposal and to complicate a possible salvage by the enemy, the crew of the battleship had packed her full of sacked cement that once submerged were going to harden and be very difficult to remove.
And that was indeed the case not for the Germans but to the English company "Liverpool Salvage Association" who had been entrusted the work.
Photo n° 12 : H.M.S Vindictive (23)
The salvage started the following summer under the direction of Captain Young who already had good experience of this kind of work.
One of the first works that would be entrusted with hard hat divers was the removal of these cement bags and thus to get there some double deck plates needed to be cut using the oxy-Secator in order to allow the demolition of this concrete layer (24 ).
This was made using pneumatic hammers and minuscule explosive charges. After that, thirty lifting tunnels were dug under the wreck so that lighters and pontoons could aid in the lift.
All the operation was led in a masterly fashion and the work completes successfully October 16, 1919. As it was a British company that had done the job it's a safe bet that some British divers had the opportunity to use this torch.
We again find the oxy-Secator a few months later in 1920 on a sheet pile cutting in Theux on the Meuse (25). In the region many structures suffered severe damage or even complete destruction because of the war and so to restore them correctly sheet curtains were driven around the structure.
At the completion of such kind of repairs and whenever possible the sheet piles were pulled out but according to the ground configuration that was not always possible and in that case the only remaining solution was the cutting under water.
Photo 13: Reconstruction of the Theux bridge (26)
It was this type of work that had been given to our underwater worker for a number of "Ransome" Type D sheet piles were completely blocked in the ground.
Figure 7: Configuration of a "Ransome" sheet pile (27)
According to a report at the time, our burner managed to cut the flat sides without too much difficulty but because of the size of the torch’s bell the interlocks and the inside angles of the sheet piles had not been completely severed and the cracking of the curtain had been necessary.
The problem with this first torch was that because of the inside volume of the bell quite a large amount of compressed air was needed to keep it dry. This was provided by a compressor at a pressure of 5 bars but because of the air bubble back-pressure the torch vibrated strongly emitting a shrill whistle and it was quite difficult to keep her against the work.
Moreover, just like the German torch, the flame tended to go out frequently.
Photo 14: Oxy-Secator provided with its Corné ignition system (28)
Luckily to counteract this disadvantage, Mr. Corné manager of scientific and industrial research and inventions had developed an underwater lighting system in the form of a brass tube in which a reactive mixture was compressed who was kindled spontaneously on contact with water allowing the relight of the torch.
In 1922 Mr. Picard who now works for the Air Liquide present at the Marseille Colonial exhibit a different kind of submarine torch on which the cumbersome bell was removed and replaced by a combustion chamber which eliminates the use of compressed air.
Photo 15: Cutting demonstration in Marseille (29)
Indeed with this new device the flame burns inside a brass protection mantel which prevents the ingress of water.
Figure 7: torch Picard AD-8 (30)
To facilitate ignition under water, the use of the Corné system is also replaced by a small pilot flame which burns continuously in the immediate vicinity of the main nozzle.
Figure 8: Details combustion chamber and pilot flamme (31)
The first field trials of this new torch will be made on the wreck of the Tubantia a Dutch ship that was torpedoed March 16, 1916 by the German submarine UB13.
Photo 16: The steamer Tubantia (32)
The boat was lying on the bottom at 33 meters deep just 55 miles off Ostend in a very busy shipping area subject to strong current.
The tests drove off in late April 1924 with a team of six divers (1 French and 5 English) but very quickly it became a fiasco (33).
The torch was burning well at that depth, but the flame was unable to bring the plate to the ignition temperature. To reach this temperature the surface team tried to calibrate the regulators to increase the pressure in the torch head, but what was bound to happen happened. A tremendous explosion occurred causing the bursting of the entire length of flexibles and also set the acetylene gauge on fire.
What had happened?
Nothing too surprising except that the new torch was working like its predecessor with an oxyacetylene mixture. But be aware that acetylene cannot if it is not dissolved in acetone be compressed above 1.5 bars. Above this pressure, the gas decomposes quickly into carbon and hydrogen and explodes spontaneously. In other words, this type of mixture can only be safely used at depths less than 10 meters.
Fortunately, this incident had no adverse consequences, but the use of the burning torch was stopped and the cutting was made by using a different method to be described later.
This first failure (which does not involve the torch) did not prevent it use on shallower sites such as for instance on the battleship of 15,000 tons Liberté which had following a fire exploded in the Toulon port September 25, 1911, killing no less 110 people and injuring 236 others.
Photo 17: The battleship Liberté (34)
The method used to lift the ship was that advocated by Mr. SIDENSNER former chief engineer of the Russian navy who had to his credit by a compressed air method the salvage of the battleship Impératrice - Marie who sank in the bay of Sevastopol in 1917 (35).
So here in Toulon the main work for the divers consisted to inject compressed air into the compartments that were not too damaged and to set up both inside and outside the wreckage a lot of big pontoons in order to achieve sufficient buoyancy to move the battleship to the dismantling place.
Needless to say that all these works that would last nearly 40 months necessitated the presence of many divers including several burners.
Indeed, between June and November 1924 three new Picard torches had been commissioned on this site during which no less than 500 hours of various cuttings were provided at a depths between 3 and 7 meters, thus far of the acetylene critical pressure (36).
Figure 9: Illustration work on the Liberté (37)
On the same site, another submarine torch appeared. It was the one of the engineer Royer, director of S.A. du Chalumeau Eugene Royer, from Lyon who in 1922 had applied to patent an oxyacetylene torch for underwater purpose.
His blowpipe consisted of a brass tube approximately 50 cm in length equipped at one end with 4 fittings for receiving the supply hoses and at the other side the head of the blowtorch.
As can be seen from the sketch of Figure 10, the flame is protected from contact with water by an air nozzle which surrounds the tip.
The Royer torch is also equipped with an in water electric ignition system and two rollers can be installed to facilitate the movement of the cutting tool on the sheet.
Figure 10: Royer gas burning torch patent (38)
Although this torch had only recently been put on the market, it seems, however, have quickly proved its effectiveness through some demonstrations organized in the ports of Marseille, Lorient, Brest and La Ciotat and in the company's headquarters in Lyon.
The torch cutting performances were (apparently) relatively high since the manufacturer announced cutting speeds in the order of 12 to 15 meters per hour. It was therefore not surprising that the appointed diver of the Royer company (probably Mr. Thudot) was asked to help on site to complete the underwater cutting of an opening 60 meters long in a very narrow passage.
About 45 meters had been cut away behind some temporary cofferdams with ordinary torches but the last 15 meters could only be done under water.
Preliminary tests were made by drilling contiguous holes with a pneumatic drill, but within 6 hours of diving only 0.8 m were cut.
Our diver had afterwards cut this strip of 15 meters (30 m cut) in length in just 14 hours (39). A few small hangers prevented the metal strip from falling to the bottom but it could easily be torn out with a 25 tons crane.
With all these specialists work ended in February 1925 and despite the extremely difficult work conditions, no serious accident was to regret in the underwater workers community.
Only some of them had to suffer the (unpleasant) effects of some residual gas explosion trapped in confined spaces.
For the record one can also report the attack of an octopus that in December 1923 threw himself on the diver Jean Negri and clasped him so hard with its tentacles that the diver had to return to the surface where his assistants had to use axes to deal with beast (40).
After this prestigious salvage the press became a little stingy with information regarding the use of these torches. This was probably due to the fact that they were now part of the basic tools divers and their use became more and more common.
Yet in France the underwater burners faced a major problem: The depth limitation on their cutting performance. Unlike those used in other countries, their torches were in the twenties only equipped with tips suitable for oxyacetylene mixture which you know were dangerous when the depth of 10 meters was exceeded .
So no doubt that for some deeper projects the companies used torches from abroad which used another cutting gas: Hydrogen.
To the calorific point of view, the temperature of an oxy-hydrogen flame is about 430 degrees lower than that of oxyacetylene but the properties of hydrogen make that this gas is not limited in depth.
It was thus necessary that the French manufacturers adapted their tool if they would not lose a significant part of the customers specialized in underwater work.
Mr. Picard was the first to react and in 1936 he developed his new torch the "Picard H7". This is successfully tested in Toulon between 1 and March 20 of that year to the depth of 38.6 m (41) and following the success of these trials the H7 is marketed in the summer of that same year.
This torch is again an equipped with a combustion nozzle and while it is powered by three hoses, one for the oxygen cutting, one for the heating oxygen and one for the fuel gas, that torch comprises only 2 valves.
One quarter-turn valve that the diver has to open fully and ensures the arrival of the oxygen and the fuel gas in the mixing tip and one circular cutting valve for the oxygen.
As on the previous model this torch also possesses a small mobile pilot flame to enlighten this device underwater.
Photo n° 18: Picard H7 gas burning torch (42)
The big advantage of this new PICARD compared to all other existing underwater burning torches was due to the fact that now the diver did not have to worry about the pressure adjustments because it could now be done based to the depth via an automatic gas control unit that stayed at the surface (43).
Figure 11: sketch automatic gas control unit (44)
Photo n° 19: Automatic gas control unit (45)
Obviously, this new model was quickly adopted by most of the French and foreign companies and during the 4 decades that followed it was used successfully on numerous sites including of course the removal of the many wrecks sunk during World War II.
The dexterity of our Elder was unparalleled.
The sections that came back to surface were often so perfectly and straightly cut that they could have been welded again without special machining.
Photo 20: lift of a wreckage piece cut off with a Picard (46)
Apart from the salvage works the H7 torch was also much used by the inshore divers to namely realize the underwater cutting of the numerous sheet pile cofferdams that had served for the restoration or construction of new bridge foundation destroyed during WWII.
Yet for those civil engineering divers two small problems would soon appear.
As mentioned above, the Picard H7 worked with an oxygen / hydrogen mixture and for the torch to work correctly the mixing ratio of these gases needed to be about 1 volume of O2 for 3 volumes of H2 which gave if we used the torch at 10 meters an hourly consumption of about 7 m³ of oxygen and 23 m³ hydrogen which means for the sole heating flame a daily consumption of about 180 m³.
To this we had also to add the 57 m³ for the cutting oxygen. This meant that the teams that were working on land had to travel with an impressive number of gas cylinders.
Once again Air Liquide solved the problem by changing the mixing nozzle. The 22 small gas exhaust holes from the H7 were reduced to 12 with the result that in the fifties the divers could now use the Picard (P9) with propane gas (and later with other hydrocarbon-based gas).
With this new model the needed proportions became equal to 1 volume of O2 to 0.3 volume C3H8 thereby reducing at the same time the handling of bottles.
The other small problem encountered in civil engineering was due to the length of the Picard gas burning torch.
Indeed, it was sometimes difficult in some sheet piling configuration to cut them all at once without changing the torch position. To remedy many companies had quickly solved the problem by removing themselves the torch handle (and sometimes more) which not only shortened the torch but also made it a little lighter.
Photo 21: Result of some changes realized within the company (47)
At about that time, end forty early fifty (date not found) another French torch reaches the market: the Charledave.
Photo 22: Charledave oxy-propane torch (48)
Equipped with four valves, the oxy-propane torch used the principle of the air bubble to prevent the extinction of the flame.
Following its users the torch was difficult enough to adjust but once done, it was cutting perfectly.
Regarding the "Royer" torch oddly enough there isn’t more of it after the work on the Liberté and no pictures seems available.
In 1939 his inventor instituted a trial with the court of Rennes against the SORIMA because he pretended that his oxyacetylene torch had been used by the Italian company during the gold recovery campaign on Egypt, which lasted from 1930 to 1932 and therefore he hoped to receive 10% of the recovered value which made approximately 9,200,000 francs (old French francs) (49).
Photo 23: Neufeldt-Kunhke armored suit (50)
When we know that this wreck was lying some 127 meters deep that can leave us as septic especially if Mr. Royer claimed he had worked with acetylene.
Another fact to the detriment of this statement is that because of the depth all dives on the wreck had been carried out with the Neufeldt-Kunhke atmospheric diving suit equipped articulated arms and it can therefore be difficult to imagine that such a suit could hold and guide a submarine torch.
On this wreck five bridges had actually been cut to get access to bullion room but following the Italian firm all these cuts were exclusively performed with bundles of explosives (51).
Today, no underwater gas burning torches are made in France only a combustion nozzle that can be mounted on a classic pyrocopt torch is still available.
Picture n°24: Pyrocopt torch equipped with a combustion nozzle (52)
To follow the American torches
(21) Pratique de la soudure autogène par Franche & Seferian encyclopédie Roret 1931 page 218
(22) L’emploi du chalumeau et de l’arc électrique dans les travaux sous-marins 19xx par Maurice Lebrun page 19
(24) Marine Salvage by Joseph N. Gores 1972 David & Charles page 252
(25) Revue générale des chemins de fer et des tramways 1921/07-1921/12 page 249
(26) Revue générale des chemins de fer et des tramways 1921/07-1921/12 page 249
(27) Revue générale des chemins de fer et des tramways 1921/07-1921/12 page 243
(28) La Nature-1921 quarante-neuvième année,premier semestre :n.2439-2464 page 416
(29) Pratique de la soudure autogène autogène par Franche & Seferian encyclopédie Roret 1931 page 220
(30) La Nature-1932 Soixantième année,,premier semestre :n.2872-2883 page 559
(31) Le génie civil.Revue générale des industries françaises et étrangères (1924/05/24) page 512
(33) L’emploi du chalumeau et de l’arc électrique dans les travaux sous-marins 1945 Académie de Marine par Maurice Lebrun page 22
(35) Le génie civil.Revue générale des industries françaises et étrangères (1925/03/14) page 250
(36) Le génie civil.Revue générale des industries françaises et étrangères (1925/03/14) page 254
(38) Le génie civil.Revue générale des industries françaises et étrangères (1925/03/14) page 267
(39) Le génie civil.Revue générale des industries françaises et étrangères (1925/03/14) page 253
(41) La Machine moderne 1936/01-1936/06 page 275
(43) DYKKEHISTORISK TIDSSKRIFT Nr 50-17 Argang 2013 page 12
(44) La pratique du soudage oxyacétylénique et des techniques connexe par A. Leroy, M. Evrard et G. d’Herbemont page 277
(46) Les Pieds-Lourds Histoire des scaphandriers à casques français par G. Millot/Le chasse-marée éditions de l’estran 1982 page 156
(47) Chalumeau BDC document personnel
(49) Paris-Soir 8/9/1938
(51) L’or et la griffe par Claude Rabault Terre de Brume Editions 1995