Diving

The diving , also called diving and deep - sea diving is the act by which man plunges into bodies of water , whether sea a lake a river a quarry flooded or pool , in order to develop a activity professional ,recreational , for scientific research or military with or without the help of special equipment. Traditional diving (without breathing apparatus) is simply called diving, although its sport modality is called apneaor free diving.The term scuba diving exactly defines the practice of diving in the sea , which is also, and by far, the most practiced diving in the world. A practiced diving in caves or galleries flooded mines is called cave diving and diving in lakes of mountain high dive .

In almost all the modalities that use breathing apparatus, the most widely used system is that of the scuba (a regulator fed by one or more compressed air bottles ). Regulator technology allows the high pressure of acompressed air reservoir to be reduced to the pressure of the water surrounding the diver, so that the diver can breathe normally and independent of air supply lines and tubes from the surface. In 1943 the FrenchmenJacques-Yves Cousteau and Émile Gagnan were the inventors of the regulators still used today in autonomous diving (both professional and recreational ). Other scuba diving devices had already been previously experienced ( Théodore Guillaumet regulator from 1838, ¹ Rouquayrol - Denayrouze regulator from 1864, Yves Le Prieur hand regulator from 1926, René and Georges Commheines regulator from 1937 and 1942, SCUBA air recycler by Christian Lambertsen from 1940) ² but it has been the Cousteau-Gagnan type regulator that has prevailed to this day, mainly due to the simplicity and reliability of its mechanism as well as its lightness and ease of transport during dives.

History and origin

There is evidence that freediving has been practiced for thousands of years to obtain food or wealth (pearls or coral, for example) and also for military purposes. Scuba diving , using a helmet and breathing air supplied from the surface, began to develop during the second half of the 18th century, but especially from the beginning of the 19th century and today it continues to use similar techniques. However, the diving suit limits the diver's mobility because he remains connected to the surface by an air hose. The inventors' search for autonomy (autonomous diving is one that does not require any connection to the surface) produced some inventions of limited efficiency throughout the 19th century, the most notable of which was the Rouquayrol-Denayrouze regulator that Jules Verne mentions in his novel Twenty Thousand Leagues Under the Sea .

But it was not until 1942 that technology was going to take a giant leap and definitely allow man to dive with total independence from the surface. In that year Émile Gagnan (an engineer employed at Air Liquide , a Pariscompany specializing in compressed gases) miniaturized a Rouquayrol-Denayrouze regulator to adapt it to the gas engines of automobiles , since the Germans were occupying France and confiscating all gasoline.Henri Melchior, Jacques-Yves Cousteau's father-in - law and owner of Air Liquide, thought then that this regulator could be useful to his son-in-law Cousteau. Melchior knew that the latter was trying to develop an underwater breathing system that would grant the diver full autonomy. He introduced the two men in Paris in December 1942 and they went to work together.

In a few weeks, at the beginning of 1943, a first prototype of a regulator was developed in the factories that Air Liquide had and still has today in Boulogne-Billancourt . Cousteau made the first tests of this prototype in the Marne , watched from the surface by Gagnan and a friend of this, named Gauthier. ³ The test of that first prototype was a failure. As Cousteau describes it in his book The World of Silence , when he was in a horizontal position everything was fine, but when he was put in a vertical position with his head up, the air escaped freely and continuously through the regulator, while when he was upside down the opposite occurred, the air came with difficulty.

In a short time Gagnan and Cousteau found the solution to the problem and designed a second prototype. ⁴ When it was finished, Cousteau was in Bandol , in the south of France, and Gagnan sent it to him by express mail. Cousteau awaited Gagnan's shipment to Bandol because his friend Philippe Tailliez owned a villa there by the sea, in front of Barry's beach. Cousteau also had a nearby villa, Villa Baobab, in the next town,Sanary-sur-Mer , but the beach facing the village of Tailliez was in a small secluded cove and was ideal for testing scuba gear. out of sight of the Germans, who were then still occupying France.

The shipment arrived at the Bandol train station one morning in June 1943. Cousteau put the apparatus to the test immediately, with the help of his wife Simone and his friends Frédéric Dumas and Philippe Tailliez .While Simone stayed on the surface wearing a diving mask and snorkel , keeping an eye on her husband during the rehearsal, Dumas and Tailliez stayed on the beach, with Dumas (an excellent freediver ) ready to intervene at the slightest sign of alarm from him. Mrs. Cousteau. This time the rehearsal was a success. ⁵ A plaque placed on the heights of this beach in 1997 by the Sanary-sur-Mer diving museum (the Musée Frédéric Dumas) commemorates that historic moment: the birth of modern diving.

The Cousteau-Gagnan regulator used a number of previous inventions to combine a bottle filled with compressed air and a regulator that delivers air to the diver when required. The compressed air cylinder, already in 1942 safer and with more capacity than the gas reserves existed until then, had been one of the advances of the Air Liquide company.

The regulator, at least in the form that Gagnan knew, had been the one invented by Benoît Rouquayrol in 1860 and adapted for diving by Auguste Denayrouze in 1864. By miniaturizing the Rouquayrol-Denayrouze regulator and adapting it to a safe, longer-lasting compressed air bottle than bottles from earlier times, Émile Gagnan and Jacques-Yves Cousteau developed the first proper self-contained underwater breathing apparatus.

From that moment on the diver got rid of the umbilical cord that held him to the surface. In 1957, with equipment manufactured by the Nemrod company, he allowed Eduard Admetlla from Barcelona to dive to a depth of 100 meters, thus setting a world record. ⁶

Based on this invention many improvements and innovations have been made in both design and quality of diving equipment , but the basic principle remains. Surprisingly, this technology has remained almost unchanged for more than fifty years.

Diving modalities

Recreational diving is practiced in two modalities: free or apnea diving ( Greek : apnoia , free lung descent to the depth of the sea, that is, without traditional scuba diving equipment), and autonomous diving or with scuba diving . Apnea techniques and self-contained airborne equipment belong to the recreational category. Recreational diving is also considered the use of enriched air mixtures ( Nitrox ) with percentages of O ₂ up to 40%, ⁷ while autonomous diving techniques with other gas mixtures ( more enriched Nitrox , Heliox , Trimix ) or the The use of air recyclers (also called "recycled breathing assist devices" or rebreathers ) are considered within the category of technical or professional diving , due to the risk and level of preparation required by the diver who uses them. According to the different schools and regulations, recreational diving is generally limited to depths of 20-40 meters, ⁸ while in professional diving , with special gas mixtures, depths of more than 100 meters are usually reached.

Free diving or apnea is dives maintaining breathing after a deep breath surface. It can be practiced without any special equipment, but the current recreational configuration consists of an appropriate mask, fins, breathing tube or snorkel , ballast, and if necessary, a suit made of heat-insulating material. It is the simplest and oldest form of diving used by man , and appears in various regions and cultures to exploit sources of food (fish, crustaceans and mollusks), useful resources (algae, sponges, corals) and resources of cultural value or economical (pearls).

In autonomous diving, the diver uses a bottle with compressed air that allows him to breathe the stored air, giving it considerable autonomy (usually around one hour). In addition to the basic equipment and the tank itself, a harness is used, a buoyancy mechanism - the integrated harness and buoyancy system are called a hydrostatic vest, a buoyancy vest (also called a stabilizer vest), a regulator (valve system , tubes and nozzles that allow you to breathe the air from the bottle), and a ballast system. However, current safety standards require a series of instruments that allow you to know how deep you are and what air pressure you have left, called depth gauge and pressure gauge, respectively. Diving computers are also becoming popular, which depending on the depth, the air mixture and the time spent underwater, indicate to the diver at any time the depth limits in which they can stay.

Recreational diving (free or autonomous) is a safe activity, but it presents specific risks that require knowledge and responsibility on the part of its practitioners. Adequate preparation, familiarity with the equipment used, knowledge and application of safety measures, a minimum of technical and physiological knowledge, and respect for the organisms of the aquatic environment are the minimum conditions to successfully carry out these activities.

Regulation, control and training

The dissemination of the underwater experience thanks to documentaries disseminated in the media (such as those by Jacques Cousteau ), research to understand the physiology of diving, and the improvement of equipment have contributed to this expansion of activity.

There are different specialties in the commercial, military and recreational area, such as underwater photography , the deep dive , dive shipwrecks , diving in caves , diving nocturnal,underwater archeology , biological research, naval maintenance, spear fishing, or rescue and recovery, or for fun, among others. The practice of some of these specialties requires prior training courses.

The physiological peculiarities of diving make it necessary to follow strict rules and respect safety limits, so the safe practice of diving (particularly in the case of autonomous diving) requires specific training. Each country is responsible for the regulation and control of this type of recreational activity, and as a general rule, a recognized degree is required that certifies knowledge of the rules and regulations, as well as in certain cases, a minimum experience, which is usually established by requiring a certain number of previous dives. The number of dives required typically ranges from 15 to 50, depending on the difficulty of the dive site.

In the world there are different certifying agencies and governmental or private entities that are in charge of guaranteeing these processes. The main ones are: World Confederation of Underwater Activities ( CMAS ) this is in charge of issuing their qualifications through National Federations, in Spain through the Spanish Federation of Underwater Activities (FEDAS ), the SSI International Diving School ( SSI ), the Professional Association of Diving Instructors ( PADI ), the International Diving Association ( IDA ), American Canadian Underwater Certification ( ACUC ), NAUI National (American) Association of Underwater Instructors ( NAUI ), (IDEA) International Diving Educators Association, and ( BSAC ), SWAT Diving- Subacuatic World Agency Training- among others. These bodies are the guarantors of the knowledge of the minimum training standards for each level of competence of their affiliated students. The different minimum safety standards adopted by these diving certifying agencies are based on those established by International Quality Control Organizations such as CMAS - Confédération Mondiale des Activités Subaquatiques, EUF - European Underwater Federation, IDSA - International Diving Schools Association, IMCA - International Marine Contractors Association, WRSTC - World Recreational Scuba Training Council and IDSSC - International Diving Safety Standards Commission. The level of certified competence of the diver is reflected in the type of qualification.

During dives in open waters and with traffic, the declaration of the activity to the other boats is mandatory by means of a "deco buoy" (warning flag). The International Code of Signalsstipulates that the alpha flag (A) on a stationary boat means "Diver submerged, keep your distance." The red flag with a white diagonal is used internationally as identification of recreational diving, but it is not valid as a warning for navigation, since it is not part of the International Code of Signals of the IMO ( International Maritime Organization ). ⁹

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