10 Hints for Improving Your Buoyancy Control in Scuba Diving

When a diver drops his feet and assumes a vertical position to perform an underwater skill such as mask clearing, he tends to kick slightly and ascend a few feet. This throws off his buoyancy. The air in his BCD expands as he moves upwards, which makes him positively buoyant. Everything tends to go downhill from there.

That's one reason that PADI has recently changed training standards to suggest that skills are taught horizontally from the beginning of the open water course. If you learned skills kneeling on the pool floor, however, there is no reason to despair. It's never too late to go back to basics and master dive skills horizontally, and you will be a better diver for it!

Many divers learn only deflate their BCDs using the dump mechanism on the corrugated inflator hose. While this method generally works well, in certain positions and situations it may be difficult for divers to release air quickly enough to avoid losing control. 

Practice releasing air from whichever dump valve is at the highest point on your body. This means you will have to choose which dump to use based on your body position. 

Additionally, practice making very small adjustments -- half bursts of air from a gentle compression of the inflation button or release tiny amounts of air from the exhaust valve. To have good buoyancy, you must learn to fine-tune!

Novice divers sometimes inflate their BCDs to move upwards in the water. But using the inflation button to ascend is just about the worst thing a diver can do!

Inflating to move upwards can lead to uncontrolled ascents because the air in the diver's BCD expands as with every foot he ascends. If you inflate to go up, you create a positive feedback loop: you move up, the air in the BCD expands, you move up faster, the air in the BCD expands more, and you fly to the surface before you can deflate.

Always swim upwards or use your lungs to gently ascend, and vent air from the BCD to keep your buoyancy under control. With a little practice, it becomes second nature!

Many divers with fairly good buoyancy control use their hands to make small adjustments to their buoyancy.

They either dog paddle slightly to compensate for negative buoyancy, or they make small upward thrusts with their hands to adjust for positive buoyancy. Most of the time, these divers have no idea that they are making these motions!

The first step is simply to notice if you use small hand motions to adjust your buoyancy, the second it so stops making these movements and to use only your lungs and your BCD for buoyancy control.

Eliminating hand movements when diving will turn decent buoyancy control into excellent buoyancy control, and make you a more stable and controlled diver. 

The hardest place to maintain buoyancy is right near the surface. The air in your BCD expands and compresses at a greater rate near the surface compared to at depth because the greatest pressure change is near the surface.

The more rapidly the air in your BCD and lungs expands and compresses, the greater effect even a small change of depth will have on your buoyancy. It follows that the hardest place to maintain perfect buoyancy is in shallow water, but if you want to get very, very good at fine-tuning, this is the place to practice.

If you can do skills, share air, manipulate your gear, hove, and swim in only a few feet of water without losing buoyancy, you can do it absolutely anywhere!

Dive professionals are relatively good at guessing how much weight a diver needs. However, information such as how much weight you used on your last dive, whether it was adequate, and what kind of exposure protection you used can help you and your dive guides to select the proper amount of weight for your next dive.

This avoids under or over-weighting, which can make proper buoyancy control difficult if not impossible. Use your log book and record information about your weights, exposure protection, dive environment, type of tank, etc on every dive. All this information is helpful when properly weighting a scuba diver.

A diver's position in the water (or his trim) has a great influence on his buoyancy as he swims through the water. In fact, perfect buoyancy when swimming is almost impossible without proper trim.

If you tend to angle either head-up or head-down in the water, you're going to have a terrible time controlling your buoyancy because any forward motion will move you slightly up or down. This will cause the air in your BCD to expand/compress, and affect your buoyancy.​

Learning to hold your body, fins, and arms in a position that will improve your trim will usually improve your buoyancy!

If you tend to angle either head-up or head-down in the water, you're going to have a terrible time controlling your buoyancy because any forward motion will move you slightly up or down. This will cause the air in your BCD to expand/compress, and affect your buoyancy.

Trim and buoyancy go hand-in-hand in scuba diving. Mastering one without mastering the other is nearly impossible. If your body position is good, but you can't stay flat, try adjusting the position of your gear to improve your trim.

Just as buoyancy and trim affect one another, a diver's kicking technique can through everything else off if it's bad. The standard flutter kick (or worse, the bicycle kick) that divers adopt during entry-level certification tend to rock a diver back and forth and propel water anywhere but behind him.​

The frog kick propels water directly behind the diver, leading to pure forward motion, which is more relaxing and won't cause a diver to ascend/ descend with every kick.

Divers who have never truly understood how buoyancy works or haven't reviewed this information in a while may benefit from a quick refresher on how buoyancy works. This article contains essential information about how buoyancy functions, as well as a step-by-step guide to buoyancy control on an average dive.