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What is a Buoyancy Control Device?

A buoyancy control device, also known as a (BCD) or buoyancy compensator, is a piece of equipment that you as a scuba diver use to adjust your buoyancy while underwater. It is an important safety device that allows divers to easily control their ascent and descent in the water and maintain a comfortable and stable position at a desired depth. This is especially important when diving in shallower waters like the Blue Heron Bridge.

A BCD consists of an inflatable bladder attached to a jacket or harness. These bladders can be inflated or deflated using the low-pressure inflator hose (LPI) that is attached to your gas cylinder. Alternatively, an oral inflation valve is available for adjusting buoyancy. You can easily control their buoyancy with these options. Some BCDs feature integrated weight pockets for achieving neutral buoyancy. You can easily add or remove weights in these pockets as needed. The goal of any BCD is to help you maintain a balanced position in the water column. This allows you to explore underwater environments more effectively.

Styles of BCDs

There are three basic styles of BCDs. Which one is right for you is largely a matter of diving style and comfort.


Most divers learn with Jacket style BCDs these days. A jacket style wraps snugly around you and the air bladder extends into the wings of the BCD that wraps around you. This means that the air is not just on your back but wraps all the way around you. This is great for new divers but many more experienced divers don’t like this style.


A wing is a BCD that is composed of 3 basic parts

  • Bladder
  • Backplate
  • Harness

The bladder is mounted to the back of the backplate and the harness is a series of straps that hold it all together and secure it to the diver. Many experienced divers like wing-style BCDs because they are highly configurable. It is even possible to buy all the parts yourself and assemble a custom BCD build just for you.


A hybrid BCD is a cross between a jacket and a wing. This is the style I personally prefer. A hybrid looks like a jacket. it has wrap-around wings just a jacket. However, unlike a jacket, the air bladder is located on the back. This gives the diver a better horizontal profile in the water. The reason I like a hybrid is that I like the bladder being on my back, but I like the fit of a jacket BCD over the harness of a wing.

Wrap Up

A buoyancy control device is an essential piece of equipment for any scuba diver. It’s one of the most important purchases a scuba diver can make. It provides the ability to control your position and buoyancy in the water, which is crucial for safety and comfort while diving. It doesn’t matter if you are diving a quarry, a lake, off your favorite dive boat, or a shore dive like the beautiful Blue Heron Bridge, if you aren’t wearing a BCD, you are a free diver, not a scuba diver. 🙂 When buying your own gear, make sure you try on different styles and different brands before settling on the one you want. If at all possible, ask if you can try it out in a pool before buying. Strap on a tank and swim around for 30 minutes or so to make sure you like the fit underwater.

A well-fitting BCD will help you dive confidently.

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