Buoyancy Compensators

     Buoyancy is caused by the difference in pressure between the upper and lower parts of the body while in the water. Individual buoyancy depends on your weight and density. To control buoyancy, you would use a buoyancy control device (BCD). Buoyancy compensators are a vest comprised of a rubber-coated bladder. This bladder inflates and deflates with low pressure.

     The backpack style harness of the control device is designed to hold the air cylinders in place. The BCD also contains pockets for smaller equipment. Additional lead weights are also used. These are attached to a separate belt and placed in the pockets of the BCD. Today, many BCD's have weight belts already built into them.