A fully inflated jacket (BCD) can sustain two adult persons floating on the surface of the water
What is a jacket (BCD) and what is it for?
The jacket or BCD (buoyancy control device) fastens the tank or cylinder to a diver’s back and keeps him safely floating on the surface.
It allows you to descend when air is released through its vent or inflator and, lastly, you can find perfect neutral buoyancy when diving in a horizontal position by adding small amounts of air from the tank by pressing the inflate button in order to find the right balance between the mix and the air in your lungs.
They are also designed for carrying accessories with their anchor points and pockets.
What are the main parts of a BCD?
The BCD consists of straps, vent or inflator, simple pockets or integrated dive weighting system in pockets (making use of a belt with ballast unnecessary), accessory-bearing anchor points, bladder, low-pressure hose and a rigid backplate to protect your back from the tank.
What do I need to think about when buying a BCD?
When buying a jacket, check its weight and its abrasion rate.
The abrasion rate represents the material’s resistance, where a rate of 400 deniers is low or medium resistance, which is enough for occasional divers, up to a rate of 1500 deniers, which is very high resistance, but with a high price tag. These are for dedicated divers who want to make the most of their dives, or for good diving centers that demand the most from their gear and want it to last a long time.
The price of a BCD starts from 150 euros, up to as much as you are willing to spend. Starting at 250 euros, you can find 400-denier models that are good value for money for occasional diving.
As with other diving equipment, you can find a wide variety of models with different systems.
Starting with the most basic, there are full life jackets like the one in the picture, where air is distributed through the back and side structure, with straps, pockets and a small anchor point for accessories. These are perfect and simple for recreational diving, weighing between three and 4.5 kilos, depending on the model. This is important when traveling by plane, as the gear will add to the weight of your baggage.
Then we have sidemount jackets, which can either be just as simple or just as sophisticated as full jackets, although with a different distribution of the bladder, as the air will be inflated only in the back, thus allowing for better buoyancy control while diving, and with more stability in a horizontal position. These models can also be lighter, making them ideal for traveling. Some technical divers prefer these models because they are smaller and you can add more tanks in the sides with special adapters, although this is not the case with all models.
Lastly, there are harness jackets, consisting of separate components, with plates and bladders of different sizes and weights. These are specially designed for technical diving, although they are equally valid for recreational diving if you like these models. Expensive and resistant, they provide superior comfort, ease of assembly and buoyancy.
How is a BCD used?
To conclude, let’s talk about how to use the most important part of a jacket, the vent or inflator.
For years now, the most common vent system was mounted in the upper left, from the perspective of a diver with the jacket on his body, although it is interchangeable with the right side, with a simple winding system in many models for either right-handed or left-handed users.
This system consists of a rubber tube that is usually corrugated. At one end, a highly resistant plastic part with two buttons. Its purpose is to inflate or release air from the jacket. In nearly all models on the market, the lower button or lower side button is for inflating the jacket, and it will function irrespective of the position in which it is used.
A low-pressure hose is used for inflating, while simultaneously connected to the vent and to the tank, in order to use its own pressurized air and carry out quick and effective inflating.
But the upper button is for releasing air. It will do this correctly only if you fully extend the vent upwards, above your head, helping the air go upwards.
In recent years, some makers have developed a different system of a built-in side vent, without a corrugated tube. It is instead lodged on the side near the pocket, as shown in the picture above. It is used in a quite similar fashion and choosing one or another is a matter of preference.
And remember, the best gear is not necessarily the most expensive, but that which is the most comfortable both in the water and out.
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