How to do a Proper Buoyancy Check

Proper buoyancy is essential for remaining safe underwater, and for diving with ease.

Many divers learn how to do a buoyancy check in their Open Water course, but forget to put this skill into practice after they become certified. They go on to guess how much weight they might need, but this can lead to problems when they switch wetsuits, or dive in different waters.

It is good to do a buoyancy check when diving somewhere new or when diving in new equipment, to ensure a stress-free dive, and to avoid problems that improper weighting can bring.

So let’s find out how to perform a proper buoyancy check, and why you should do it.

How to figure out how much weight you need for scuba diving

To start a buoyancy check you will have to estimate what you might need to enter the water, and then from there you can adjust as necessary.

A general rule to follow is to add roughly ten percent of your body weight to your weight system. This will give you a good jumping off point.

However, some factors will make a difference to how much you will need. For example, diving in freshwater or saltwater (you will need extra weight for salt water), and how thick your wetsuit is (a 7mm wetsuit is a lot more buoyant than a 3mm wetsuit and therefore need more weight added to counteract the extra buoyancy).

Weight systems

There are different options to wear your extra weight while scuba diving. These are the two most common choices:

  • Weight belt: You most likely used a weight belt in your Open Water course. It is the most common way that divers wear their weights. It is a belt that wraps around your waist, and lead blocks with holes in the middle are threaded onto it. A weight belt comes with a quick-release buckle that can be opened and closed easily, which makes it easy to make adjustments to weighting, and to remove the belt in case of an emergency.
  • Integrated weights: Some BCDs (buoyancy control devices) come with integrated weight pockets that can be inserted into compartments in the sides. Most divers use lead blocks (the same as on the belt) to add weight to the pockets. Once the pockets are in place, they can be clipped in and secured to ensure they will not drop out. But the clips are usually easy to release to make adjustments, or in case of an emergency.

It is good to experience both ways of wearing your weight and decide which feels most comfortable for you, before buying your own equipment.

When/where to perform a buoyancy check

At the end of a dive is the best time to perform a buoyancy check, when your tank is emptier. This is because it is important to be able to stay underwater for a safety stop, and estimating your weight with a full tank might not give you enough weight to keep you under when the tank becomes lighter. It is better to have a little extra to start with, than to not have enough at the end.

Try to perform your buoyancy check in calm waters with little to no current to ensure it is stress-free.

Perform the buoyancy check every time you dive in a new wetsuit, and every time you dive in different water. If you use a different sized tank, or a tank made from a different material to the last time you dived, you will need to perform a buoyancy check again.

How to perform a proper buoyancy check

You will remember this skill from your Open Water Course, but to refresh your memory, and ensure you are doing it properly, let’s go over how to perform a proper buoyancy check:

First, don all of your diving equipment, including your estimated amount of weight you think you will need. Enter the water with a full BCD and make sure that you are too deep to be able to stand.

Next, deflate your BCD fully while the regulator is in your mouth and you are breathing at a normal rate. When the BCD is empty, you should still be floating on the surface (at about eye level) while you are breathing normally.

Finally, breathe out fully and you should sink under the water.

If you sink under the water while holding a normal breath, you will need to take off some weight and try again. If you are still floating when you exhale fully, you will need to add a little weight and try again.

Why good buoyancy control is important

One skill that makes a great diver is good buoyancy control. There are many reasons why perfecting your buoyancy is beneficial to yourself and to those around you:

  • Visibility: Divers with poor buoyancy control often kick up sand or silt from the bottom, this creates a cloud and affects the clarity of the water. This can make it hard to see all the beautiful sights of a dive.
  • The environment: We love our fishy friends and we do not want to destroy their homes with our fins or hands. Poor buoyancy control could mean kicking or hitting corals or animals under the water.
  • Safety: Poor buoyancy could lead to diving emergencies. For example, making an uncontrolled ascent and hitting a boat or missing a safety stop, becoming separated from your buddy or dive group, or touching hazardous marine life such as box jellyfish or fire coral.
  • Increased bottom time: Good buoyancy can improve the rate at which you consume your air. This is because you are not expelling so much energy from kicking and sculling, and therefore do not get out breath as easily. 

Good buoyancy control is beneficial for many reasons. If you would like to improve your buoyancy, think about taking a Perfect Buoyancy specialty, where you will learn advanced buoyancy skills and techniques to help you get the most out of your dives.