I do not claim to be an expert at buoyancy control, nor am i qualified to teach anyone, but believe I learnt quite a bit during my peak performance buoyancy course back in 2006.. So I'm here to share some of the things i've learnt!
Why Buoyancy Control?
Some of the reasons why buoyancy control is important:
1. Control your depth. I'm sure nobody wants to crash/land into corals and/or other divers below you. Neither do you want to exceed your depth unknowingly.
2. Enjoy your dive better. good buoyancy control means you don't have to keep focusing on maintaining your depth, which means you can relax more and enjoy looking at fishes or doing other things that divers normally do! (no, taking out your regulator to give to the fish is not a normal thing)
3. Fin less. Finning is tiring! with good buoyancy control you don't have to be finning constantly to maintain your depth, trim or posture.
4. Better air consumption. Some say because you play with your inflator less so that you waste less air. I think more importantly, when you dive relax, you breath calm, slow and easy. When you fin less, you also breath less air. So you can stay underwater and play with the fishes longer!
5. Fine position control. control your position using only your breath so that you can get closer to interesting things without stirring up slit (from finning) or kicking into things
What to expect?
At a recreational level, it is important to recognize that having good buoyancy control does not mean you can do cool tricks like perfectly horizontal trim, helicopter turns and other stuff that the technical divers do. Having good buoyancy control means to me that you can control and maintain your depth (both rough and fine control) easily and almost effortlessly.
The limits of recreational gear configuration means that some of the things tech divers do will be very difficult for us recreational divers to achieve. For example, wearing a weight belt or integrated weights is the standard way of carrying weights for recreational divers. The position of such a weight system (usually around the waist or lower part of the body) usually results in a head's up position. A perfectly horizontal trim position while stationary is almost impossible in some cases. There is nothing wrong with it.
And since you are reading this, I assume that you WANT to have better buoyancy control. The next thing is to actually focus on it while diving. A lot of divers go down expecting to do a lot of things like chasing after turtles, and sharks, searching for sunken treasure etc. But to have good buoyancy control, it is necessary to focus on it. At least initially until it becomes second nature.
Tips for buoyancy control:
1. Proper weighting.
The problem most new divers face is being overweighted. (I'm not saying you're fat!) It means you are carry more weight than you need! As a result you are in a constantly heads up position trying to fight a losing battle against gravity.
Perform a weight check on the surface every time you change new equipment or have not been diving for a while. Being properly weighted means that you can float at eye level while holding a normal breath, on a empty BCD and near empty tank (50 bar). Of course, realistically it is often impractical to do at the start of a dive, so you can test with a full tank and add 2kg of weights to it. (The 2kg is according to the books, but my personal experience is that 1kg will do for 80cuft al tank.) You will start to sink when you start to breath out.
This step is extremely important!! It is the most fundamental and yet most often overlooked step. Less excess weight = less drag = improve performance for pt 2 below = better diver! =D
Note: Do not be pressured by other divers that are eager to get underwater. Taking the time to do this properly on the surface can greatly improve your diving experience! It's worth it! trust me! There's no need to feel embarrassed for fear of looking like a noob. I'm a noob too!
2. Breath Control.
I find this the second most important skill. Try this. breath in and out normally, notice how much you are inhaling and exhaling. Then try to take a deep breath, in and out. Notice how much more you are inhaling and exhaling. Next, try taking an even deeper breath. Inhale and exhale more. Now exhale even more. Inhale till your limit, then exhale till your limit. then exhale some more.
Do this a few times. You will realise that your lung capacity is actually very big. On your next dive, try to notice how you are breathing. how much of your lung capacity are you actually using?
Try the various combination/sequence of breathing:
Speed of breathing. (eg, inhale fast but exhale slow will make you raise slowly.)
Depth of breath. (eg, Breath out deeply, then breath in normally. This will reduce the lung volume. Breathing in deeply and breathing out normally will increase lung volume. Warning: do not take shallow breaths or hyperventilate! Too shallow a breath results in ineffective gas exchange due to the dead air spaces in mouth, wind pipe etc. The partial pressure of oxygen at depth might be sufficient to keep you awake, but reduces when you ascend causing you to blackout!!)
Practice using only your lungs to achieve fine positional adjustment!
Remember the golden rule: NEVER HOLD YOUR BREATH!
Holding your breath might cause lung over expansion injury which could be fatal!
It is important to perform step 1 before doing this. If not, being over weighted (hence more drag) means that the effect of each breath to your buoyancy is actually reduced. So you might not notice anything. See also point 3 below.
3. Think Slow Motion.
A lot of times, people expect instant reaction when diving. Eg, they expect to raise immediately when they inflate their BCD, or sink immediately when they descend. This expectation is normal; on land, we take a step forward and we expect to move instantaneously! But diving is more like the matrix scene where everything turns to slow motion and you can see the bullets fly by. (Please don't try this on your next dive trip! shooting at ppl is dangerous! =p)
Due to the viscosity of water, pressure changes, current etc etc things actually take time to happen underwater. Take your trigger happy finger off the inflate/deflate mechanism. Trigger happy finger on camera is fine. After you inflate your BCD, WAIT for a while and see if anything happens. Say to yourself "IMUSTWAITANDSEEIFSOMETHINGHAPPENSFIRST!" five to ten times. slap your own itchy hand if needed. =p
This is also related to point 1. The more drag you have, the more 'slow mo' you need to think. hahah..
4. Visualization.
Visualization is a technique used by many top athletes to improve their result. It basically involves closing your eyes and imagining the whole process of diving, down to the details. Find some quiet time, close your eyes and take deep breaths. Imagine yourself diving underwater. focus on your posture. You want to achieve a horizontal trim.
Focus on your breathing. With each breath feel the raise and fall.
Focus on your finning. Are you finning the correct way? (proper flutter kick vs 'jabbing' the water)
focus on the things that i mentioned in this article. Imagine yourself getting better at it. Imagine yourself having excellent buoyancy control. what are the things that you need to take note? What should you do if you want to raise a little or descend a little?
5. Dive Plan
Everyone knows what an ideal dive plan should be like. Down to the maximum depth, maintain that depth until nearing the end of the dive, then ascend. Strive to achieve this. Frequent depth changes (eg. yoyo dive profiles) make it hard to adjust your buoyancy. It's a vicious cycle. You keep changing your depth => your buoyancy changes due to ambient pressure => you adjust your air in BCD, but that doesn't seem to work cuz your depth is constantly changing => you think that you have not enough air in BCD => you inflate BCD more => you finally ascend, but too much=> then you dump and so on. You get the idea.
6. Equipment.
I choose this as the last point because many people think that you can replace poor skills with good equipment. that is only true to a certain extend.
a. Streamline your equipment. Less drag = better buoyancy control!!
b. Look at your equipment. Is the weight distributed evenly? Are some of them too heavy resulting in poor posture? a good example is Jet fins. Many ppl think that it is good so they want it. But then Jet fins are HEAVY. in the end a lot of them end up with a heads up posture and expend a great deal of energy trying to maintain horizontal trim.
c. Backplate. It is generally easier to achieve better buoyancy control with backplates rather than jacket style bcd for two reasons.
Firstly, the normal jacket style BCD has air pockets all over the place, making it hard to adjust the amount of air in the BCD precisely. Usually, only a single bladder is present in backplate style BCD, so it's easier to control the amount of air inside precisely. Also, the donut shape of the badder allows for the air inside to shift around to accommodate any posture you adopt.
Secondly, the metal plate on the backplate BCD usually distributes the weight evenly over the upper body, making it easier to achieve horizontal trim. On certain configurations, (eg steel backplates) some might not even need a weight belt.
The downside with backplate is that it usually floats you face down, which is not a problem if you lean back!
d. equipment that changes buoyancy. A common example is the wetsuit. The neoprene material compresses under pressure, reducing in volume and hence has lesser buoyancy. The principle here is to reduce the number of buoyancy changing equipment down to as little as possible. Minimise the variables so that you can focus on the things that matter. But in certain cases exposure protection is a must and this is unavoidable.
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Now, you've read quite a bit, but the best way to improve your buoyancy is to actually go out and practice it!! Now go dive and have some fun!! =D
Hope it helps! drop me a comment if you have any questions! =)
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