What Is a Buoyancy Control Device (BCD) and How Do You Use It?

buoyancy control device
5 Nov 2021

What Is a Buoyancy Control Device (BCD) and How Do You Use It?

In the world of scuba diving, your BCD or buoyancy control device is one of the most essential pieces of equipment. But, what is it? And, what does it do?

If you’re looking to learn more about this important gear, vital to floating and sinking during your dive and safety on the surface, you’ve come to the right place! Keep reading for a basic primer on BCDs.

Buoyancy Control Device Basics

Most divers refer to their buoyancy control device simply as a BCD. This item is used to impact your buoyancy in the water – both for staying positively buoyant or floating on the surface and for making fine-tune adjustments during your dive.

BCDs come in a variety of styles, from traditional wrap-around jackets to backplate and wing setups, and even small bladders used for sidemount equipment, popular among cavern and cave divers. But they all work pretty similarly.

Add air to your BCD by using its inflator hose before entering the water, and you’ll float. Remove that air by venting, and you’ll sink.

This helps divers to relax on the surface, descend to start their dive and return to the surface when they’re done. It also helps them maintain perfect neutral buoyancy throughout their underwater exploration!

How to Use Your BCD When Scuba Diving

If you’re still wondering how to use a buoyancy control device, don’t worry. We’ve got you covered.

You already know that you’ll need to release the air from your BCD to descend and start your dive. Then, once you’ve reached your preferred depth, you’ll need to make some adjustments.

First of all, you’ll want to check for neutral buoyancy. This divers’ term refers to an object that neither sinks nor floats in the water – hopefully, in this case, that object is you!

To check for neutral buoyancy, take a deep breath in. If your chest and shoulders rise through the water, you’re probably pretty close to neutral. If not, you’ll need to add a tiny bit of air to your equipment. That’s where the BCD comes in!

Using your inflator hose, you’ll add one small burst of air – then repeat this same process until you’ve found neutral buoyancy. Remember, you should always add air slowly. Because your BCD is taking pressurized air from your scuba tank, it will expand rapidly – one small “click” of the button at a time is best.

As you ascend or move to shallow water, you’ll need to release any air that you’ve added to the BCD by venting. This is because, according to Boyle’s law, air expands as it moves into shallower depths. Keeping too much air in your buoyancy control device can cause unwanted floating – or even a rapid ascent.

Then, when your dive is done, you’ll want to fully inflate your BCD on the surface while you swim to shore or wait for a boat to pick you up.

Put These Buoyancy Control Device Tips to Use

Now that you know a bit more about how to use a buoyancy control device, it’s a good idea to get your hands on one and try it out in person. Practice inflating and deflating your BCD above water, getting your hand used to operating its inflator hose and vents. Then, you’re ready to get wet.

Keep in mind; you should always have a full or near-full BCD when you’re on the water’s surface. This will help you save energy and remain buoyant while you wait to begin your dive or return to a boat or the shore. You should also test any and all new equipment in a swimming pool or other controlled environment before taking it in open water.

If you’re ready to buy your first BCD, start, or even continue your scuba diving education, you’ve come to the right place. Contact Scuba Guru to schedule your course, log some practice hours at Dutch Springs, or get pro help shopping for gear!