Equipement de plongée sous marine
I/ Choosing your scuba tank
Floating seems easy when you're lying on the surface of a swimming pool. Keeping your body horizontal seems like child's play.
Aluminum scuba tanks are the most popular -- possibly because they're cheaper -except in some country like UK where there are the same price-, but also because they're a lot easier to lug around. These lightweight tanks - not lighter than steel but more buoyant in the water for the same size - may require you to carry more weights with you if you wish to descend to greater depths, yet are perfect for those surface and reef dives.
II/ How about your wet suit
Equipment that you would be wise in investing are that of the fins and mask, as well as a decent scuba wetsuit. The scuba wetsuit can afford you the opportunity of staying in the water a little longer, as well as diving in colder water regions that you would have not ventured into, had you not invested in a scuba wetsuit. The scuba wetsuit is available in various sizes and designs, from the shorty wetsuit to the full steamer suits, which cover the entire body. The thickness of the wetsuit is relevant in terms of how cold the water is that you will be frequently diving in. It is necessary to get a good fitting scuba wetsuit to allow the item to function correctly when you go scuba diving.
Extensions of the scuba wetsuit include the neoprene hoods and booties, which provide a good source of insulation for the whole body, which is ideal in very cold water conditions. Therefore the mere fact that you will be visiting or going on holiday in a colder water region does not mean that you will have to give up your scuba diving passion. It is vital that you follow the care instructions of your scuba wetsuit and accessories, as the salt water and sand that may get into these items can cause the neoprene and other materials to perish before they should, hence a good rinse in freshwater after a dive is highly recommended before anything else.
The scuba wetsuit, and other personal items are a valid and necessary purchase for those wishing to pursue scuba diving on a regular and consistent basis, as these items will enhance the experience as well as add functionality in terms of protection and insulation.
III/ Then your scuba fins...
Choosing the proper scuba fins can save energy, air and unnecessary hassle. The right pair can feel like natural appendages, powerfully propelling you forward with each little thrust.
The Mares Volo design puts the blade at the best position on both upward and downward strokes, allowing for optimal propulsion. Experienced divers also recommend Apollo brand scuba fins , which are the only fins to score perfect in the Rodale Magazine evaluation.
IV/ ... and the BCD...
When a diver wants to buy a scuba diving BCD, they have usually only used a set of school diving equipment, and don't really know the options available. The first question most people ask when faced with a shelf full of BCDs is 'What is the difference' or more to the point 'What am I paying for?' - in this article I will explain most of the common features found on current scuba diving BCDs and who they're aimed at.
First of all I should explain that most jacket style diving BCDs are largely the same - the main difference is usually whether they have an integrated weights system or how heavy/feature packed they are.
How does the Scuba Diving BCD fit?
This is the SINGLE most important factor to consider when buying a BCD. The most feature packed BCD, with the most rave reviews in the dive magazines is useless if it is uncomfortable. For this reason always try on a BCD before you buy it. You should consider:
1) How does the cut of the BCD feel - does it cut in under your armpits or is there plenty of room? For ladies, consider a special ladies jackets.
2) Can you get in the pockets? A lot of BCDs have ridiculously inaccessible pockets that are basically useless!
3) How does the BCD feel when fully blown up? The BCD must feel fine when fully inflated otherwise you will feel the discomfort when at the surface.
4) Does it drag when you put a tank on it? If possible, get your dive centre to put the tank on your BCD and let you see how it feels - now would be a good time to play with the tank buckle as some are better than others.
Air Release Valves
Scuba BCD´s usually have three release valves plus another one next to the inflator valve. One is positioned on the lower back usually on the right hand side, the other on the top right hand side and the third on the top left hand side and this one you can pull with your inflator valve hose.
How much lift does the Scuba Diving BCD offer?
A surprisingly common question is whether a BCD will offer enough lift - do not worry about this - all modern BCDs will offer you plenty of lift, the fit of the BCD is much more important. If you really want a number to gauge, around 10-15kg of lift is enough for all basic recreational scuba diving.
Rings in the shape of a “D” are excellent to clip on extra gear. Make sure your BCD has at least two of them. You can always add more on if necessary.
The idea behind integrated weights is to take some of the pressure off your hips and back, and spread the weight about a bit more. When you first start out you generally use more weight than you need, and might not be sure about integrated weight systems. Luckily most BCDs allow you to either use or not use the weights as you see fit; you can just leave them out if you like.
If you have the money, and have decided upon a jacket style BCD, its best to get one with the option of integrated weights. Typically you can put up to 5kg in each weight pocket.
One point to make is that putting all your weight in your BCD is NOT recommended, as this means you can't dump it all quickly in an emergency like you could with a weight belt.
Weight of the Scuba Diving BCD
The weight of the BCD can be a very important factor especially if you plan to travel or not. On scuba diving mainly in Europe, go for a sturdy and rugged BCD which can stand up to the typical European diving conditions. If you plan on scuba diving like in Asia then go for the lightweight option - don't try and go for an in between scuba diving BCD, it won't be totally suitable for both, and will cost you in airport fees.
So to sum it up, when buying a scuba diving BCD, choose one that fits even when fully inflated with a tank on, and if you can afford it get one with the option of integrated weights so you leave your options open. If in doubt, keep it simple!
V/ ...the first stage...
The first thought when shopping for a scuba regulator is to decide where you will be doing most of your diving. Will it be in warm water destinations, or areas where the water can be cooler or even cold. Will the regulator be used in both cold and warm water?
Next, decide on a budget. There are many manufacturers and all of them have various price ranges, based on the features and benefits of each model as well as what conditions are best for each model. Think in terms of how long you plan to keep diving.
Most of the major manufacturers have replacement parts available for regulators that are well over 20 years old. Also, remember that this is life support equipment!
Various types of regulators
The simplest and the type that has been around the longest is the piston regulator. This type of first stage (the part that connects to the scuba tank) has fewer moving parts and has simpler maintenance requirements. Another advantage of a piston first stage is it's high air flow. Typically piston regulators can generate higher air flows than other types of first stages, but this comes with a price. Piston first stages are not as reliable in colder water than other styles, but some manufacturers have incorporated various devices and technology to help prevent regulator malfunction in these conditions.
The next style of first stage is called the diaphragm style. Diaphragm first stages are the best for cold water, silty conditions, or even for salt water, as the moving parts are protected by a diaphragm. These regulators have more moving parts and can require a bit more maintenance due to their complex designs, but the reliability overrides this concern.
Some diaphragm first stages also incorporate what is known as "environmental sealing". This technology uses a second diaphragm on the first stage to give extra protection against very cold
water and under ice diving conditions. Many divers choose environmentally sealed first stages due to the fact they can be used in any type of diving circumstance.
First stages also fall into two categories of "balanced" and "unbalanced". Balanced first stages will deliver the same flow of air, no matter what the tank pressure is, while unbalanced first stages will allow less air to flow as tank pressure drops.
Unbalanced first stages are usually at the lower end of the price spectrum.
The first stage has a number of ports. Some of them are high pressure ports that connect to the pressure gauge or dive computer. Those ports require special high pressure hoses and have a different thread than the low pressure ports. Low pressure ports connect to low pressure items: the second stage with the mouthpiece, an alternate breathing source, a hose for inflating the BC or dry suit, and perhaps an blower or a hose to power tools.
First stages also differ in the number of low pressure ports and the type of valve they connect to (A-clamp "yoke" or DIN fitting, or both). The more ports, the more hoses can be connected, and the easier it is to connect at just the right angle. The first stage shown above to the left uses a yoke design.
VI/ ...and finally the 2 second stages...
Most second stages can be grouped into two major types: balanced and unbalanced.
The lever that opens the valve upon inhalation is controlled by a spring inside the second stage. In unbalanced (some refer to this type as a "mechanical") second stages, the spring is rather stiff. The advantage of this is that the second stage is less likely to flow a lot of air in "free-flow" conditions; in other words, the second stage is less likely to malfunction. The downside to an unbalanced second stage is that the air flow is reduced, consequently not as easy from which to breathe.
On balanced second stages, the spring used is of a lighter construction, with air balancing or counteracting the spring tension, thus making these second stages extremely easy from which to breathe. These tend to be on the high end of the price range.
Other features on many second stages include venturi assist levers, which control the direction of airflow. Sometimes these are referred to as "free flow" controls. The function of these levers is to direct the flow of air through the mouthpiece in a straight line (easiest air flow) or slightly interrupted (less likely to flow air continuously). Another feature on higher-end second stages is an adjustment knob, which controls the trigger of the regulator.
These have some benefits, in that the user can control how easy the second stage breathes. In deeper dives, the control is opened for maximum air flow, while diving into currents requires the control to be slightly reduced so the second stage does not waste air.
Maintenance is an important issue. Remember, we are dealing with life support gear. Many manufacturers offer a lifetime warranty on their regulators, provided the original purchaser brings the regulator in for service to an authorized dealer at least once per year. The dealer will inspect and clean the regulator and replace any parts needed to keep the system in top condition, and adjusts it to factory specifications.
To sum it up here are important points to keep in mind:
* Ergonomic design and easy to hold. It is important to try the mouth piece.
* A purge button which is easily pressed even when wearing 6mm neoprene gloves
* External controls which let you make fine adjustments to air flow
* Non-corroding metals like titanium or chromed brass
* Diaphragm vs. piston mechanics. Many divers prefer diaphragm regulators for its smooth movement and its moving parts are less
* Balanced vs. unbalanced regulators. Almost all regulators are balanced. Do not buy an unbalanced regulator.
* Always buy new. Do not pick up a cheap second-hand regulator; it may be faulty or reconditioned
* Look for a lifetime warranty
* Swivel joints on the second stage offer improved ease of movement
* Hose should be soft and flexible
* For the octopus preferably use colorful hose, bigger diameter.
VII/ ... but dont forget the mask !
The right scuba mask can make or break a dive. It is hard to enjoy a dive if your mask is constantly leaking or fogging.
Scuba Diving Mask Types
Single Lens Scuba mask
– Remember the old 007 movies where Bond was fighting the villain underwater and the type of masks they wore? Those rounded oval masks are single lens. They are nowadays much more stylish and squarer on the sides to give you a wider angle of vision.
Double Lens Scuba mask
– Same as above only the lens is divided in the middle just above your nose, so you have two lenses. They are most common type of scuba masks found in the market nowadays.
Multiple Lens Scuba Mask
– There are many diving masks styles with multiple lenses on the market. This style of lens could be just like a single or double lens type described above but in addition either it could have small lenses on the sides of the mask to help your peripheral vision and or smaller lenses on the bottom to help you visually locate your scuba gear on your BC.
Scuba Masks with Purges
– All the scuba masks mentioned above can come supplied with or without a purge. A purge is a one-way valve that lets you clear water by exhaling into the mask. Purges can come on the bottom of the nose or on the side of your scuba mask. This last one to clear the water away, you will have to tilt your head to the side where the purge is and exhale. I have never had one of these, but some diving buddies have told me that sometimes the purge can block and even some have problems equalizing the pressure while on deeper dives.
Integral or Full Face Scuba Mask
– These masks cover the whole face of the diver. They are mostly used by professional divers or when for some reason verbal communication is necessary and these masks can easily be fitted with that device.
Tips for choosing the Right One
Following along the lines of which type of scuba mask you should choose as mentioned above, you have to consider as well with each and every scuba mask you try, which one gives you a better field of vision.
Nose fitting is important, not too tight not too loose. Pay extra attention to the fitting and comfort on the top part of your nose. This is where a lot of people fail when buying a mask and then find out after their first dive that the bridge of their nose is a bit sore.
There is various quality degrees of silicone used on masks skirts. On the more expensive masks you can notice the silicone skirt more flexible, softer and “gluey” as you try it on your face.
Pending on your scuba mask buying decision, a double strap can be bought separately for your mask if it comes only with a single strap. Double straps are more comfortable on your head and hold your mask better.
To make it short in few points :
* Wide field of vision to permit you with greater visibility underwater
* Good seal and comfortable skirting with a close fit against your face
* Tempered Glass lenses - These types of masks provide additional safety for the fact that if they were to break, the glass is less likely to shatter in fine small pieces
* Nose pockets enabling you to equalize during descents
* Low profile mask which enables easier equalizing due to the lesser volume of trapped air
* An adjustable strap which can easily be locked in place. (Note that some cheap masks have straps which are fused to it. Should the strap tear, the mask will be rendered useless).
VIII/ Consideration on computers
Serious scuba diving entails more than just the basic gears of the beginner diver. The diver needs more than just his set of mask, fins, regulator, oxygen tank, and wet suit to ensure the diver’s safety.
For external data that the diver should know, the assistance of a diving computer is essential. The diving computer provides information on the amount of time needed for decompression and even the depth of the dive itself. It also gauges data such as the levels of nitrogen content in the bloodstream, or decompression sickness that could be fatal to the diver’s life.
It would be wise to compare brands of diving computers before actually making a purchase. Aside from considering factors such as cost, quality and accuracy of the machine should also be weighed out. One effective way of doing this would be to search for reviews of the products and gather consensus of those who have bought and used it in their dives.
After buying one’s personal choice it would be prudent to study and understand the features and commands of the equipment. It should be known by heart, in the same way that a beginner is trained to deal with various situations that can happen to him under water. To get used to operating the product, it would be advisable to use its functions little be little in short-term expeditions.
Various unforeseen accidents can occur to a diver, especially when he is underwater. One trick is not to panic and to remain calm. Fear is a diver’s greatest enemy since it can blur out good judgment and training. Besides, another aspect that should be checked from time to time is the relaxed breathing of the diver. Panic can cause hyperventilation or worse, rapid ascent towards the surface can cause bubbles to form in the body’s tissues that could cause lack of sensation, immobility, or death.