Contemporary buoyancy compensator (BCD) designs have an array of special features that can turn an ordinary buoyancy compensator into an extremely helpful adjunct to the diver’s gear. Many designs today will provide straps and padding for integrating the tank with the buoyancy compensator. Some will even have integrated regulators and hose assemblies. The specific size and shape will determine, among other things, where the tank rides on the back. A low-slung tank can be a literal pain in the butt. Some will make the tank ride higher. That keeps pressure off the base of the spine and makes for a more comfortable dive with less chance of bruising. Backpackers will be familiar with the principle that having the pack higher on the back up to a point makes for an easier haul. Some wing styles will even have an integrated steel backplate, which makes carrying a tank easier, but adds weight.
Traditional buoyancy compensators have an inflator/deflator over the left shoulder. But not everyone is right handed. And, not everyone has long arms, making using the device difficult. Several new designs have the inflator lower on the chest to allow for easy reach, and some can be found on the right side.
A buoyancy compensator can be inflated using a separate tank – in days past even carbon dioxide was used rather than air. But, nowadays, filling the buoyancy compensator from the diver’s main air tank is the most common method. As a result, several have special valves which allow for breathing from the bladders in the jacket during an emergency.
Newer designs often come with handy extra pockets to store items taken down or picked up during the dive. Some are large enough to carry an extra mask.
Others have D-rings that allow the attachment of ropes that can be used to haul up a diver or tie a tether between buddies. D-rings can be used to attach extra gear you may want to take down during the dive. Bags to haul up shells and other finds from the deep can be attached to the jacket using the D-rings.
Special ‘travel buoyancy compensators’ are made especially lightweight, but often have only very basic features. One optional feature which helps the travel aspect is the use of an integrated alternate inflator/regulator. These make a separate emergency regulator (an ‘octopus’) unnecessary and allows the diver to have a spare while still controlling buoyancy.
Heavier-duty styles will usually offer the option to add weights to a wing-style buoyancy compensator in order to compensate for the tendency to force a diver onto his or her face at the surface. Weight systems are often made up of special pockets that can be added or removed as desired.
Look for a buoyancy compensator with plenty of dump valves, usually located on the rear right shoulder or the rear left hip. Most will have at least two. These allow for easier deflation, but you should still be able to operate them with your eyes closed.