How To Achieve Neutral Buoyancy When Scuba Diving

How To Achieve Neutral Buoyancy When Scuba Diving

During the PADI Open Water course, you will have learned about neutral buoyancy, why it is important and how to achieve it. But if you are reading this, there may be some gaps in your knowledge, or maybe you haven't quite been able to apply that theory in practice when you get in the water.

Once you are able to apply the theory in practice, which is totally achievable for all divers, your diving experience will become so much easier and more enjoyable. You will probably find that you reduce your air consumption in the process too.

In this blog we are going to share some top tips that will help make this easier for new divers and old divers alike!


Lets get started

This Step By Step Guide To Preparing A Diving Spool includes:

  • What is buoyancy?
  • Wearing The Correct Amount Of Weights
  • Check Your Weighting At The End Of The Dive
  • Avoid Adding Too Much Air
  • Develop Breath Control
  • Vent Excess Gas From Your BCD Before Ascent
  • Cave Diving Lines

Lets dive in.

What is buoyancy?

Determining whether an object floats or sinks is called buoyancy. There are three types of buoyancy, which include positive (an object that's lighter than the fluid), negative (an object denser than its surrounding liquid environment) and neutral buoyancy (the state when the average density of an objects equals to a specific fluid it's immersed in). Neutral Buoyancy can be achieved by balancing with gravity just like you would if you were sinking or floating.

Neutral buoyancy is a condition in which a physical body’s average density is equal to the density of the fluid in which it is immersed. The buoyancy offsets the force of gravity that would otherwise cause it to either sink (if the body’s density is greater than the density of the fluid in which it is immersed) or rise (if it is less). An object that has neutral buoyancy will neither sink nor rise.

Why should a diver become neutrally buoyant?

When you are over-weighted, you typically compensate for this by adding more air to your BCD. This is the logical solution. What you may not realise is that this increased weight is most over-weighted divers do not realize is they are exerting additional effort throughout the dive by dragging around the unnecessary amount of weight they are wearing; which in turn increases the diver’s rate of air consumption, shortening the dive, and adding post dive fatigue.

An over-weighted diver might find it troubling to stay off the bottom and accidentally damage the bottom contour of the environment they are in whether it’s a beautiful reef, wreck, or even disturb a critters home in the sand.

So what does it mean to be “properly” weighted? When properly weighted, the diver should be able to comfortably hover at a safety stop (at the shallow depth of three to six metres or 10 to 20 feet) without popping to the surface, without exerting any effort to stay down, and without struggling to kick to maintain neutral buoyancy at the end of a dive. With the cylinder now near-empty, the diver should need little to no air in the BCD to hover motionless at the safety stop depth.

How to do I master a buoyancy check?

One mistake scuba beginners often make is not exhaling when deflating their BCDs. You should always be sure your tank valve is open before attaching/detaching any part of your equipment from a diving regulator.

Correct weighting and good breathing control are both key to diving neutrally buoyant. Ensuring that you are not wearing too much lead will make this so much easier to achieve.


Wearing The Correct Amount Of Weights

The key to achieving neutral buoyancy is having enough weight. The problem with many divers is that they wear too much or not the right amount of weight, which causes them to sink instead of float in water at eye level. A good way for new divers and experienced ones alike to check their weights before entering the water is by breathing all air out until you're nearly empty then checking your height underwater; if it's neck-level, there isn't enough weight while sinking means there's probably a bit extra on board. As you will have learned during your entry level training, try adding or removing weight until you float at eye level.


Check Your Weighting At The End Of The Dive

You know all of this, but the bit that makes all the difference is completing the neutral buoyancy check at the end of your dive after surfacing. Aim for between 35-50 bar for this exercise. If you need to empty a little gas from your cylinder, no problem, just make sure you do not complete this with an unsafe amount of gas and make sure your buddy is with you while you do it.


Avoid Adding Too Much Air

One common mistake divers make when they start diving is over use of the power inflator or drysuit inflate button. Adding too much air all at once and becoming positively buoyant or deflating too much allowing yourself to have negative buoyancy means you will constantly be compensating. This is often a common sign of too much weights in your weight system. Ensuring that you have the correct amount of weights will reduce your need to over use the power inflator.


Develop Breath Control

You may not know this, but your lungs actually act as natural buoyancy compensators. If you need a minor adjustment, all you need to do is inhale and exhale. For example, if you want to take a rest at the bottom of the water then when descending slowly just exhaling will help compensate for any excess weight in your BC causing it go down less than usual.

With this in mind learning how to control breath can really make or break how much compensation occurs with an added load on our BCD's so be careful about taking deep breaths!


Vent Excess Gas From Your BCD Before Ascent

One point in the dive that causes divers problems is during the ascent. When you start ascending, gas expands causing increased upwards movement. The more you ascend, the faster you ascend, the more the gas expands. With this knowledge, we can preempt and reduce the chance of this problem even starting. When you start your ascent, exhaust a little gas to make sure you are just a little negative, you will be able to swim against this small negative buoyancy. This does not mean fully deflate, however, if you have

means that you need to vent air from the BCD when you need to ascend. Vent as much air as needed so can rise to the top. Being underwater is great and makes one feel calm, but once a person attains neutral buoyancy they will enjoy it more fully in this relaxed state of mind

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