Scuba diving equipment: BCDs

The BCD is an expandable bladder or bag that you inflate or deflate. Its purpose is to help you achieve neutral buoyancy underwater. The BCD is also used to keep you afloat at the beginning or end of a dive.

There are 3 styles of a BCD: front mounted, jacket style and wings. The front mounted style is no longer used by the general scuba diving community as the jacket style has proven to be the most convenient.

The jacket style consists of a built-in bladder which goes around the torso of the body. It has a low pressure hose which is used for inflation and deflation.

Wings are generally used for technical and specialist diving as all the air is held in a bag on the back of the diver. These systems are preferred because of their larger volume and the horizontal position in the water. The negative of this system is that on the surface they are very difficult to maintain an upright body position in the water.