How to Control Buoyancy Underwater
Controlling buoyancy is the most important aspect of enjoying your dive, besides having a good, fog-free mask. The feeling of weightlessness is the reason many people love to dive. Seeing cool things is, of course, at the top of the list, but if you cannot control your buoyancy you will not be able to enjoy the underwater sights.
Buoyancy is a skill divers constantly practice and is one of the most difficult to master.
There are several ways to adjust buoyancy once underwater.
The jacket. This piece of equipment can inflate and deflate and is fine to use for larger adjustments especially when diving in colder temperatures where more weight is needed to counteract the amount of neoprene worn to keep warm! Remember, you only need enough weight to counteract the flotation of your equipment. Many novice divers confuse buoyancy with adding more weight. Take a refresher on how to perform a buoyancy check and stick to the results.
Adding or subtracting weight will affect buoyancy. Many beginning divers use too much weight and have a difficult time counteracting the downward pull. This leads to other problems. You feel as if you are sinking. So you kick up. You are exercising more which means you are breathing harder, filling your lungs, which is also causing you to go up. You think you need more weight and add more which only exacerbates the problem. The least amount of weight you can use, the better off you will be. Notice how much weight your instructor or divemaster uses.
LUNGS – The lungs are the most important part of buoyancy control.
Have you ever floated in a pool, or ocean, on your back and held your breath, and then slowly let it out? If not try it. You will at first float with full lungs, and then slowly sink as you let your breath out. This is the key.
Think of your lungs as having 3 parts. The upper, middle, and lower. Breathing in the middle of your lungs is the normal way your breathe when you sleep. Deep and steady. Think Darth Vadar breathing. This type of breath should be comfortable. If you find yourself sinking using this breath, remove weight or add a small amount of air to your BCD. If you find yourself floating using this breath, add weight or empty air from your BCD.
After establishing neutral buoyancy with your middle breath you can begin the fine tuning. If you wish to raise up in the water column, breathe in more and out less. When you achieve your target depth return to your middle breath. The exact opposite is true when trying to go down in the water column. Breath out more and in less. This is also true of the initial descent. Relax and breathe out.
Just remember if you added air to your BCD at a certain depth and ascend, that air is expanding and will cause you to rise faster than you expect so ALWAYS DEFLATE while ascending until you obtain proper buoyancy again.