If you’ve had little to no first-hand exposure to scuba diving, you may be overwhelmed and a bit hesitant to get involved due to the misconception that, in order to take part in the pastime, you need a zillion different pieces of equipment. The truth is you can get by just fine with a relatively small amount of gear. Among these is an air bladder known as a buoyancy compensator or buoyancy control device (a BC or BCD for short).
As the name implies, a BCD’s primary function is to control the manner in which a diver floats. This is done by adding air to – or expelling it from – the bladder. This allows the diver to attain three types of buoyancy: negative (in order to descend or remain on the bottom), neutral (in order to remain at a certain level) and positive (in order to ascend or stay at the surface). Air is added from the diver’s tank through the regulator, but in emergency situations the BDC can also be manually filled via a mouth tube the diver blows into. Throughout the years BDC’s have evolved in terms of appearance and technology, but currently two main types predominate:
Jacket/Vest Style BDCs resemble their namesake, appearing as a sleeveless garment that fits around the chest and fastens in the front. In these models, the air bladders are located at the wearer’s sides and back. Many divers favor this style because the configuration allows them to float vertically at the surface with little effort. This setup is also popular because many models feature accessory pockets and clips as well as weight systems and attachment points for air tanks. Some individuals, however, feel that they are too bulky and tend to compress the upper body when inflated.
Backplate/Wing Style BDCs have the air bladders (or wing) positioned between a metal backplate and the air tank. The backplate lays against the diver’s back and is fastened to the wearer via shoulder, waist and leg straps. The main benefit of this setup is the relative freedom the diver experiences without air bladders along the sides of the body. Many models are able to lift more weight than a jacket/vest BCD, and some backplates can accommodate two air tanks. A major drawback to backplate/wing BDCs is the tendency for the back-mounted air bladder to push the diver into a forward-facing vertical position. This can result in a serious problem if a diver is on the surface unconscious or injured and unable to right themselves.
So what’s the best BCD to buy? Many divers favor one type over the other and some like both, but in the end the decision is a personal one. The best way to make up your mind is to try on – and dive in – a few different makes and models and see what suits you best.06/05/2012