A Buoyancy Control Device is perhaps one of the most important accessories for scuba diving. The basic use of a BCD is to control and manipulate the buoyancy of a bladder style container that's attached to a jacket. Manipulating the buoyancy essentially allows a diver to move up and down through the water or to stay afloat at a certain depth.
The fundamental mechanisms that control a Buoyancy Control Device include pumping or releasing air through different chambers. A simple pumping action adds gas to the BCD and increases the buoyancy of a diver. A quick release of air in the BCD decreases the buoyancy of a diver and allows for easy sinking to lower depths.
A Buoyancy Control Device should be tightly secured to the body of a scuba diver. This device is similar to a large hiking backpack. A BCD includes multiple straps and belts that make it easy to secure to the torso, back and arms of a scuba diver. Of course, a BCD is used to carry the oxygen tank for scuba diving missions. Additionally, this sophisticated device has multiple compartments and pockets for carrying important items such as signaling devices and other marine tools.
A BCD is available in different sizes and weights and it's important to select the right type for your particular body type. A BCD that is too bulky can interfere with your scuba diving experience. Keep in mind that metallic components such as stainless steel are essential to a BCD and they cannot be substituted by other lighter materials.