Your buoyancy control device is what makes the difference between ‘flying’ underwater and wallowing like a hippo in a mud-hole…..

A Buoyancy Control Device

A Buoyancy control device (BCD), aka Buoyancy Compensator (BC), is a piece of scuba dive gear, vest-like in appearance which is responsible for a scuba diver’s buoyancy, whether at the surface or underwater during a dive.

Descriptive diagram of a BCD

It is filled with air or deflated by way of the Inflator hose or air 2 coming from your regulators first stage , there is a inflate button and a deflate button to add or remove air according to whether you need to be more or less buoyant.

Once you have undergone your scuba certification, you will have learned about neutral buoyancy, negative buoyancy, positive buoyancy and their role in your diving – not least of which is what effect it has on air consumption….. very basically if you are not neutrally buoyant you are either swimming hard to either stay under the water or stay off the bottom – all that exertion will make you breath harder and therefore use more air – MUCH shorter dive and quite exhausting!

The Buoyancy control device comes in three main styles:

There are 3 main types of BCD’s made today.

  1. Stabilizer Jacket
  2. Back Inflate Vest
  3. Back plate and Wing

The Stabilizer Jacket is more of a ‘wrap-around’ Jacket where the air bladder extends under the arms and around the waist. The diver will generally be pushed into a more upright position, although it is said that the air within the bladder will move around the inside causing the diver to maintain a position more easily than perhaps a back plate BC would.

The Back Inflate Vest is a back mounted bladder and tends to keep the diver in a more horizontal position whilst underwater.

The Back plate and wing consists of a detachable wing which is generally used by technical divers requiring additional lift/buoyancy due to the added weight in equipment they tend to carry with them – additional cylinders as well as hard equipment.

Things to consider:

Integrated weight pouches

Integrated weights

You will either use integrated weights or a weight belt. Integrated weights are pouches which usually slide into purpose designed pockets on the BCD. In my opinion, apart from the convenience of handling as opposed to a weight belt, the distribution of weight makes your balance under water much better than with a weight belt and it is MUCH more comfortable. The pouches will usually (Check this....) accommodate the average lead weight as well as the various modern types of weights available now.


It is quite convenient but not essential to have at least a couple of pockets on your Buoyancy control device, where you can carry small items – like a torch for instance….. actually the only thing I could think of while writing this - I know for sure I have often thought I wish I had more pockets on my BCD!

‘D’ rings

'D'-rings are metal rings, funnily enough in the shape of a 'D' which are located in strategic positions on the Buoyancy control device to use for attaching accessories so you dont lose them underwater.
I am the gadget King, and I always need somewhere to attach that extra carabiner, or on a night dive when I have my DSLR camera, my torch or during the day, my deploy buoy (submersible marker buoy – SMB) etc.

Air Dumps

Not every Buoyancy control device has these – they are a valve which is usually located up near the right shoulder and sometimes a second is located at the base of the Buoyancy control device. They are there for safety purposes as well as convenience – it is a quick and easy way to release either a small amount of air, or a lot of air in an instance of emergency. On the diagram earlier in the page they are called an 'over pressure relief valve'.
Even if just considering convenience they are a plus point.

A Buoyancy control device is a not cheap scuba gear item and it may well be an idea to investigate a few different makes and designs before buying yours. The dive shops will be able to give you a lot of advice (hopefully unbiased and not just for the sake of the scuba gear sale). The only way you will really get to try out the gear properly is to dive in it – realistically then, are you going to take that much time over choosing the BCD?
Again as with all scuba gear, it is a matter of personal choice as well as what you get used to.
I will source user reviews and post them here in short order which will assist in getting some practical observations.
The leading brands are all leading brands because they produce good gear and you will find the choice will boil down to appearance, comfort and convenience, all of which will be quite easy to gauge in the Dive Shop.

A final comment from me is on the subject of used scuba gear. My opinion is generally you should be very careful about what you are buying and why the person selling is getting rid of it. If you are going to buy the used scuba gear see if you can get the gear checked by a scuba gear store to make sure it is either in good order or what is required to get it into good order before you buy it.

Scuba Diving Magazine did some reviews on Buoyancy control devices in their May issue to read them - Click Here

Leave Buoyancy control device review page and return to Scuba diving equipment page click here

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