Scuba Diving Buoyancy Control Tips

Scuba diving is simply great fun and the sooner you master the use of your basic scuba gear the faster you will be able to reap naturally each and every dive´s amazing wonders!

Good buoyancy control means longer and relaxed dives, less fatigue, drastic reduction in the possibility of scuba accidents and greater enjoyment.

As a novice you will have trouble with your scuba BCD in the beginning. You will use excess air in trying to attain that correct buoyancy at your pretended depth. You will roll all over the place, rise too fast, sink too fast and scrape your knees on the sandy bottom if not on rocks. You will feel frustrated but don´t give up. Keep on diving and practicing your buoyancy control.

Get acquainted with your scuba BCD and you´ll see that in no time you´ll be mastering buoyancy control and not even thinking about it. Yes, eventually buoyancy control will come out naturally so you can enjoy fully your dive.

First of all there are many reasons that affect your buoyancy that you need to be aware of.

  • Inhaling and exhaling
  • Adding and releasing air from your scuba BCD
  • The thickness of the suit you wear
  • Diving in fresh or saltwater
  • Adding or removing weight from your belt
  • Diving tank capacity
  • Aluminum or metal diving tank
  • Pretended diving depth
  • Your body weight

Buoyancy control tips. First the basics

Pending on the thickness of your scuba diving neoprene suit, a diver commonly needs 1kg of weight for every 10kgs of body weight. If you weigh 70kgs for example, then probably you will need 7kgs of lead around your waist.

Mind you, this is for sea diving. In freshwater will need around 25% less weight. So following that 70kgs example, you will only need approximately 5.25kgs of lead.

Getting the weight right in fresh or saltwater

Following what I’ve just mentioned above, you need to, in practice, find out the necessary weight you require for good buoyancy control. Firstly you have to practice this in a body of water where it´s calm, so get access to a freshwater pool.

Gear yourself up and make sure your scuba BCD is completely empty, no air whatsoever in the bladder.

If you are using an aluminum diving tank, make sure it is full. If your diving tank is made of metal it´s best to get to that buoyancy control level if the tank has got only 70 or 50 bar.

Get in the water with 2kgs less than what you´ve calculated. Remember you´re in a freshwater pool. Stick the snorkel in your mouth.

What you are going to be aiming for is to have the water level right across your mask, level with your eyes, and with your lungs half full. Be calm because this takes a bit of patience and practice.

Slowly and by using small weights, remove or add weight until you have reached that level with your lungs half full.

When you have reached this level you should have just your chin submerged when you fully inhale and when you fully exhale your head should be fully submerged with only your snorkel sticking out of the water.

Remember that as you are diving, your tank as it slowly empties will become positively buoyant. This is more pronounced diving with aluminum tanks then with metal ones.

Having said that, remember that towards the end of a dive and while you are ascending to that 3 meter safety stop, you could be positively buoyant. So add a bit of extra weight the first dive just in case and remove weight in small increments the following dives.

Do not overload yourself with weight, reasons are:

  • Less weight you have to carry around loading and unloading the better
  • Less air wasted in filling your scuba BCD
  • Less strain on your back while in the water
  • Greater ease in getting neutrally buoyant
  • Better hydrodynamics
  • Less energy consumed swimming
  • And finally, less air consumption resulting in more bottom time. Isn´t that were all the fun is?!!!

More Buoyancy control tips

Still in the pool, there is an exercise you can practice that greatly helps you in attaining and mastering that buoyancy control you so need.

When you got your weight right and your scuba BCD empty, lay flat and face down on the pool floor and with your fins flat on the floor as well.

Stiffen your body and do not over inhale or exhale. Try to keep your lungs in the half full range.

Now slowly inject small bursts of air into your scuba BCD. As your scuba BCD fills it will raise you but just enough to the point where only the tips of your fins are touching the floor.

Your mask then should be about 30 to 50cms from the floor.

Now still with your body a bit stiff, slowly inhale and exhale more. Don´t panic and fiddle to fast with your scuba BCD if you feel being pulled up, you could lose balance. If you power inflate very slowly it won´t happen.

With your lungs full you should be at almost a 45º angle and fully exhaled, your mask barely touching the floor.

This is an excellent exercise for buoyancy control. While enjoying the pleasures of diving and when you need to overcome that protruding and higher rock, all you need is to synchronize your breathing to overpass the obstacle. No air wasted in filling your scuba BCD, but more air for yourself.

Remember this as well

The exercise described above helps you locate your center of gravity. You want to be diving on a horizontal plane and not almost vertical.

Don´t forget to add 25% more weight for sea diving as in relation to freshwater

The most thrust you get when kicking your fins is being horizontal and not at an angle. So you can play and tweak a bit with the location of some weight.

Your scuba BCD back padding will slowly release air, as some are made of sponge.

Your wetsuit will lose buoyancy as you descend. The air bubbles in the neoprene will compress as you dive deeper. In time and with quite a few dives on top, your suit will not only lose its buoyancy capacity but insulation as well. One of my wetsuits, a 5,5mm when bought new, was slowly and in time squashed to 3,5mm after 300 dives.

While diving and breathing normally, adding or releasing air from your scuba BCD, this takes time to go into effect. This effect will not be immediate and if you don't give it a bit of time you will definitely overinflate or over deflate and waste precious air.

Do it safely and enjoy diving!

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Comments 3 comments

Karen Ellis profile image

Karen Ellis 6 years ago from Central Oregon

Great and extensive article. Good work.


china man 6 years ago

I have been diving super and sports dive trainer most of my life. Good sensible advice, nice hub.


nelson soares profile image

nelson soares 6 years ago from Sunny Algarve Author

Karen Ellis & china man, Thanks. Diving is truly a great pleasure! I´ll be writing more on diving and tips in the near future!

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