A BCD or buoyancy compensator device, in essence, is a bladder that allows you to control your position in the water. Fully inflated it will comfortably maintain you at the surface of the water. Underwater adding and subtracting air will allow you to effortlessly maintain a state of neutral buoyancy.
BCD © Highlander411
- Jacket or Wing
It’s most common to find recreational divers using a jacket style BCD that fits like a waistcoat. The bladder surrounds the diver and air will flow around in response to the diver’s orientation. On the surface, this design will support the diver in a vertical position.
A wing style configuration includes a horseshoe or donut-shaped bladder which attaches to a backplate. This backplate is fitted with a harness that is similar in nature to backpack straps. This configuration is more typical for technical divers as it positions the bladder on their back, allows for greater lift, redundancy, and less bulk at the front which makes carrying extra tanks easier. Hybrid style BCDs do exist that marry the BCD jacket with a wing bladder. This design still locates the bladder at the divers back which is great for a horizontal position under water, but it will push the diver face forward on the surface.
Either style should be adjustable so that it will fit you comfortably and but a jacket style will offer more padding and a cut tailored for comfort. Both configurations will have rings for you to attach accessories but a jacket style BCD usually has pockets for storage. Many BCDs incorporate weight and trim pockets which allow you to spread your weight for better positioning; most divers find an integrated weight system more comfortable than a belt. - Travel BCDs
Travel BCDs are lighter and more compact and stripped back to their simplest form. The material used is thinner, straps will be slimmer, and metal rings replaced with plastic. While they still stand up to a lot of diving, they’re not rugged. If all of your diving is on holiday and you like to take your gear then consider buying one. If you dive mainly at home, in cold conditions, from a packed RIB, on wrecks then this is not the choice for you.
Buoyancy
Your BCD must have enough lift to support you on the surface when you are wearing full gear. Smaller BCDs will have smaller bladders and therefore less buoyancy. If you are small but dive cold water check your BCD is going to have enough lift to support the extra weight you need to carry for increased thermal protection. - Comfort and Fit
After making sure a BCD has enough lift, your next concern is comfort and fit. Ladies cuts are available, but it’s not unusual to find a female diver in a standard or unisex BCD. Try a few on and make sure that you inflate them to check their comfort, consider their size and fit over your exposure protection. Where possible, it’s good to try diving in a few different styles to see what you do and don’t like. - Valves and Inflation
A low-pressure inflator hose connected to your BCD from your regulator allows you to inflate your BCD using air from your tank; you can also inflate your BCD orally. The LPI is connected to the same inflation device that, via a wider hose acts as a dump, raising it and pressing a button will release air. Make sure this device is easy to use and feels comfortable in your hand particularly is you have small hands. Each BCD will have an emergency overpressure release valve on the shoulder which will stop the bladder bursting due to overfilling. It is possible that this valve incorporates a manual dump activated by a string and toggle device, again make sure this is comfortable to use and easy to locate. A further dump valve can often be located on the lower backside of the jacket near your bum. This dump valve allows the diver to release air while in a horizontal position.
You can incorporate your alternate air source into the LPI inflate/deflate device which would reduce the number of hoses required and therefore weight. Naturally, this hose would be shorter, in an out of air situation you would pass the regulator from your mouth to the out of air diver and take the one incorporated into you BCD for yourself. As this differs from the standard configuration is could cause confusion at a time when fluidity is required.
The final variation that you might notice is an inflator device located around your lower rib areas. This offers streamlining as you do away with the bulky hose, it also means that your inflator mechanism is always in the same place however it does make the overall unit heavier.
