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Diving equipment
Scuba diving
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شرح معدات الغوص
صفات الغواص
تعبير انجليزي عن أنواع المنازل
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Scuba diving is, in general, exploring the underwater world equipped with specific scuba gear usually consisting of a wetsuit, mask, flippers and, unlike snorkeling , a scuba tank , a regulator.
The main purpose of recreational diving is to discover the underwater world , its fauna, its flora , its beauty, its particular sounduniverse . There are also specific activities, in particular professional, related to diving (dive instructor for example). Thus, a diver can be a caver, biologist , offshore diver, combat diver, clearance diver, photographer, archaeologist, wreck researcher , etc.
Just as there are many different types of divers, there are many different types of diving or underwater activities such as underwater hockey, freediving, spearfishing , etc.
Equipment
the diver's basic equipment consists of fins, mask, snorkel, knife , wetsuit , the rest can be rented on site. However, in order to acquire complete autonomy, it is important to quickly have your personal equipment in addition to the bases mentioned. - Buoyancy compensator (or any other means allowing an ascent to the surface and staying there using compressed air) - Regulators (Main, octopus and pressure gauge) - Computer (or failing this, a means for controlling the parameters of diving) -Parachute landing
Rebreather
Breathing
Under water, the respiratory reflexes are modified: indeed, on the surface, inspiration and expiration are automatisms. Under water, the work of breathing is more difficult because of the pressure which increases and becomes voluntary. The complex mechanism that takes place within the alveolus is modified, the CO2 becomes more difficult to evacuate, the risk of shortness of breath becomes significant.
(the contributor will complete this paragraph as soon as possible, because what was written was false and potentially dangerous to follow).
diving suit
Choice of breathing mixtures
Divers' cylinders may contain Nitrox, Trimix , Heliox, air or pure oxygen, depending on the type of dive and the level of the diver. Air is the most widely used gas these days because it is much easier to compress into blocks. Air being much more common is also much cheaper. Nitrox is gaining ground as it extends no-stop dive times. The maximum safe depth achievable is however reduced by oxygen enrichment, which makes nitrox less flexible than air. For low enrichment rates (less than 40% oxygen), nitrox is used with conventional equipment, provided that it is very well maintained. For higher rates, specific equipment is required (cylinder and regulator) due to the corrosive effects of the oxygen-enriched mixture.For high enrichment rates, there is also a risk ofexplosion if inappropriate seal greases are used. Finally, note that only a suitable dive computer can perform the calculations necessary to establish the level of saturation of the diver when using a gas other than air.
Thermal protection
Heat exchanges being greater in a liquid medium, the calorie loss is relatively high during a prolonged stay in water. The diver must therefore limit the heat exchange between his body and the water. He can use for this:
• non-waterproof suits (also called wetsuit), most of the time in Neoprene. They can be one-piece or two-piece. Their thickness varies from 2mm to 7mm with the possibility of putting a double thickness in the case of two-piece suits (thus 14mm);
• dry or semi-dry suits for lower temperatures.
The diver can lose up to 75% of their body heat through the head in the absence of thermal protection .
For the heat loss to be negligible, the water must be at a temperature above 32°.
Buoyancy
The diver uses a stabilizing jacket (also called "Stab" for "Stabilizing Jacket") which he can inflate and deflate at will in order to vary its volume and, following Archimedes ' principle , change its buoyancy and thus balance itself in water. The "stab" can be inflated automatically with the "direct system", which is connected to the block and which allows gas to be injected from the bottle. It is also possible to inflate it by mouth, but this is generally not recommended: for hygiene (fungi can form inside; this place is rarely dry and disinfected) and because of the risk of shortness of breath , pulmonary overpressure or ADD.
Shift
Movement underwater when diving is provided by the legs. For the sake of performance and economy of effort, the diver equips himself with flippers. Single fins are of two types:
• footwear: the fin has a slipper that surrounds the foot, the diver can optionally put on a first neoprene slipper to fight against the cold .
• adjustable: the foot must be equipped with a boot (slipper with sole) before being put in the palm, and the tightening is then adjusted.
Several types of swimming exist:
• ventral: the most common, the swimmer placing himself horizontally, belly facing down.
• dorsal: often used to rest while continuing to swim, mainly on the surface. The advantage of this type of swimming is to be able to get your head out of the water easily.
• lateral: swimming sideways. Used when diving on drop offs (underwater cliffs, most often home to significant and characteristic fauna).
In the context of so-called drift dives, the current can serve as a motor : the dives are launched at one point and recovered by the boat further away. These dives are particularly interesting because a great distance can thus be traveled, and a large numberof things can be observed, all with a minimum expenditure of energy .
There are small electric underwater scooters that allow the diver to move effortlessly, however, these require great experience and are totally prohibited in nature reserves (in France for example).
Dive computer
Coming in the form of oversized watches, dive computers are supposed to replace the use of dive tables. They generally provide the following information at all times:
• instantaneous and maximum depth.
• dive time.
• decompression stops.
• ascent rate.
• water temperature.
To this can of course be added various options depending on the model:
• management of different air gases: nitrox, trimix, heliox.
• integrated manometer , connected by radio transmitter to the cylinder.
Using an algorithm specific to each brand/model, and depending on the depth, the computer will calculate the diver's decompression parameters. This calculation makes it possible to determine according to the profile of the dive what will be the durations and depths of the possible stages. If the definition of a dive is: "several divers having the same characteristics of time, depths and direction during the same dive", in practice, it is possible that some members are lower longer than others. 'others.Their dive profile will be different, the decompression protocol too. In addition, the practicality of the computer is the calculation of the automatic markupduring repetitive or consecutive dives and to adapt the decompression calculation accordingly.
It also measures the ascent speed according to its own algorithm predetermined by the depth and signals an ascent that is too rapid (by means of a beep and its display).
Regulations
International regulations
The knowledge of the constraints related to the aquatic environment as well as the strict respect of the regulations, are essential to the practice of this sport classified as high risk. The individual is free to practice on a personal basis. Two major organizations oversee underwater activities: PADI (especially in America) and CMAS (generally in Europe ). They provide training and guidance to athletes, but their regulations do not act as law, it depends on the countries where the sport is practiced.
Regional particularities
France
In France, in commercial or associative structures, scuba diving is regulated by the following two decrees:
- relating to the technical and safety rules in establishments organizing the practice and teaching of sports and leisure activities in scuba diving . Commonly referred to as "arrested 98"
- relating to the technical and safety rules in establishments organizing the practice and teaching of sports and leisure activities in autonomous diving with mixtures other than air . Commonly referred to as "arrested mixing".
These two texts regulate scuba diving (sports or so-called leisure) due to the particularities of this discipline which is carried out in a specific environment , with the exception of archaeological sites which are considered as professional activities even if one participates in as a volunteer and cave diving where the only point of regulation concerns gas mixtures. On the other hand, theSports Code generally regulates the practice (and the conditions of practice - supervision, etc.) of all P hysical and SportingActivities ( See The Sports Code on the Legifrance site)
Professional diving is regulated by a text from the Ministry of Labor (Order of 92).
Also visit the INPP website for more information on training and professional diving.
Quebec
Originally modeled on the model in force in the United States, ie training provided by instructors most often supervised by shops, the training failed to instill in instructors, shopkeepers and especially divers notions of individual responsibility. The result was an inordinate number of diving deaths in the 1990s, including an unacceptable number during training courses.Consequently, the Government of Quebec has legislated to regulate the practice and especially the teaching of diving in Quebec.
The organisms
Diving involves certain risks related to the effects of pressure (barotrauma, decompression accident, toxic accidents) or to the underwater fauna and flora (stonefish, fire coral , etc.). For these reasons, local regulations generally require obtaining a patent in order to practice. It is a patent obtained during training in a scuba diving teaching organization recognized by the legislator or a patent recognized in equivalence.
Preservation of the marine environment
Coral reef Acropora sp. in Reunion Island _
A diver must respect the world he explores. Under no circumstances should it behave like a predator and bring up living organisms. Spearfishing using a diving suit is strictly prohibited in many countries (including France) and tourist leisure activities such as snorkeling are regulated.
Additionally, a diver should not:
• feed the fish (feeding);
• cling or cling to the bottom (living organisms are found there, some of which can be dangerous such as fire coral);
• degrade the environment with its fins (corals, gorgonians, posidonia for example);
• throw rubbish into the sea (this is valid for everyone!).
Diving in nature reserves comes with a number of even stricter rules.
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