How to Choose a Buoyancy Compensator for Scuba Diving

Keeping buoyant

In its simplest form, a buoyancy compensator, or BC, is merely a bag that you can put air into during the descent and let air out of as you come back up. Why do you need to do that? Although your body is more or less neutrally buoyant, it is not compressible like most of your equipment. However, the air in the tiny bubbles that form the neoprene of your suit is.

As you go deeper, your suit compresses with the increasing pressure of depth and you lose buoyancy because it displaces less water. You appear to get heavier. As you come up again, it regains its volume and recovers its buoyancy. By adding air to a BC or letting it out according to your circumstances, you can compensate for any changes in pressure.

To make it convenient to use, the buoyancy cell is contrived to be part of the equipment you wear. The air you put into it underwater rises to the highest point, which is normally at your back, near the top of your shoulders. This air comes from a hose fitted between the BC and your regulator. Small amounts are fed into the BC as and when needed from your main supply.

The BC has another important function. It can be filled to its maximum capacity so that it acts as a flotation device for the diver. This means that you can remain comfortably at the surface when required.

If you are at the surface but your tank is out of air, you blow into the BC via a flexible corrugated hose and an oral inflation valve.

To let air out, most BCs are equipped with dump-valves operated either by pulling on the corrugated hose or by pulling on a separate cord and toggle or both. As a last resort, you can always lift the corrugated hose and let the air out by opening the oral inflation valve. However, this will let water back in the other way, which only adds to the weight of your equipment when you climb out of the water.

Types of BC

BCs come in various shapes. Some are jackets, whereas others are simply large bags attached to the back of the harness. The jacket BCs can keep more air low down under the water when the diver is bobbing at the surface. The bag BCs, or ‘wings’, can be large and so give far greater maximum flotation.

Some BCs are made with a single bag construction, whereas others are composed of a bag within an outer lining. The first type gives a sleeker more aqua-dynamic line, whereas the second is more hard wearing.

Useful functions

Probably the most important function of a BC is that it holds the tank on your back. Then there are all the peripheral functions that a BC might have, such as integrated weight pockets, trim weight pockets and pockets for carrying things in. Stainless steel D-rings allow you to clip on items, such as lights, and to clip away gauges on hoses.

Filed Under: Sports & Fitness


About the Author: Cody Riffel is a regular contributor to MegaHowTo. She likes to write on variety of topics, whatever interests her. She also likes to share what she learns over the Internet and her day-to-day life.

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