A few tips about buoyancy compensators
The buoyancy compensator is one of the most important pieces of equipment you will have to consider. It is also one of the largest, as it fits over the entire torso of your body like a sleeveless hunting jacket.
The buoyancy compensator jacket is a multipurpose device that provides many benefits.
Purpose
The primary purpose of this device is to provide flotation on the surface in the
event you run out of air, experience a leg cramp or encounter some other type of emergency.
The secondary purpose is to provide positive buoyancy (lift) underwater to counteract any
negative buoyancy created by wetsuit compression or error in weightbelt calculation.
Another benefit of the buoyancy compensator jacket is the availability of large pockets
for carrying items such as a writing slate, portable torch, set of no decompression tables
and so on.
The buoyancy compensator jacket is also used as a holder of your alternate air source,
instrument console and any signalling devices (Dive Sausage/air horn/strobe light) that
you may be carrying. In essence, the buoyancy compensator jacket is an all purpose device
for carrying most of your dive accessories.
Design
Modern buoyancy compensators adopt two kind of designs:
- Surrounding air volume design.
- Rear air volume single-bag design.
The surrounding air volume buoyancy compensator, undoubtedly the most popular among amateur
divers, is suggested for use with single air tanks. It has the advantage that the air volume
is attached to the diver around the waist thus assisting vertical set-up under all conditions.
The rear air volume buoyancy compensator also known as "technical" and/or "all at the back"
was specifically designed to compensate for negative thrust caused by heavy sets of air tanks
when the entire weight is supported on the diver's back.
It is quickly gaining popularity also among recreational divers due to the greater comfort
it offers inside and outside water.
Producers have also started to offer new jackets especially designed for women
that better adapt to women anatomy. The first models were usually much smaller than men BC and
sometimes did not provide enough buoyant lift for diving in temperate waters with increased
weight. Recent models have eliminated this drawnback.
Materials
The buoyancy compensator is made of a heavy weight, extremely durable fabric such Nylon 420
or 840dn, Cordura 700/1000dn or Bioflex, coated in a thick layer of polyurethane then
sealed using the radio-frequency technique and seamed.
The use of modern materials has made the "twin-bag" design, i.e. an internal air chamber
and an external sewn protective chamber, less popular.
Today, in fact, divers tend to prefer "single-bag" design that, despite being as
robust as twin-bag, is both lighter and smaller in the water and out.
Accessories
The airtight compartments of BCs are accessed by an inflator device. It
operates on low pressure air supplied via the scuba regulator and can also be
used to orally inflate the compensor .
The buoyancy compensator is also equipped with one or more deflation valves.
At least one of these valves operates as a combination over pressure relief valve (automatic)
and a manual deflation valve.
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