Diver using Buoyancy Control

Buoyancy Control

David Mansfield


Scuba diving provides a platform in which skill refinement is a constant opportunity. With every dive into the depths, scuba divers find activities on this submerged frontier that captivate interest and allow exploration into areas that many humans have yet to set fin! Whether it is searching for submerged cities that are brought to life through the efforts of archeologists or the observation of plant and ocean life, scuba divers find themselves with a set of skills that are commonly accepted ways to make the experience more enjoyable.

Buoyancy Control

One such common skill is the control of buoyancy. To fully understand the concept, one must first delve into the reason why buoyancy control is so important. From the perspective of the diver, buoyancy control provides numerous advantages. Having proper control can equal less work, which means less breathing. If one is breathing at a normal, controlled rate they will find that dives underwater will be longer because the bubble maker is not taxing the contents of the scuba cylinder. Additionally, having the ability to glide through the water will ensure avoidance against items that may be of danger or discomfort to the diver. For example, a sea urchin has a well known defensive measure in that it shoots tiny barbs into one's skin when it is assaulted. If there was a lack of control in buoyancy, one might find an uncomfortable meeting with one of these creatures. A sea urchin sting is almost always a result of carelessness when descending into the underwater realm. 

From an environment perspective, the ocean is a beautiful aspect of the world. The intricate living system is fragile and, in most cases, old. The fish are adapted to this environment and rarely touch the reefs. A scuba diver has to adapt to this environment and this is done through repetitive scuba diving. An individual with poor buoyancy control will find themselves skirting the bottom and destroying delicate reef and plant life needed to sustain this underwater ecosystem. If scuba divers lack the skill of buoyancy, they may single handedly change the dynamics of a reef system through their destructive practices of poor finning, buoyancy and negligence towards the delicacy of the region they dive within. 

In either case, scuba divers find themselves constantly refining techniques and finding ways to avoid contact with the reef systems we find in our oceans. 

Proper Weighting

One of the most important steps in buoyancy control is the determination of proper weighting. If a diver is wearing too much weight, they are essentially working against their own body. The presence of extra weight translates to drag while traveling through the water. Additionally, extra weight requires a diver to add a larger amount of air to the buoyancy control device (BCD). This can create a situation where managing the air inside the device much more difficult. It also wastes air that is in the scuba cylinder, thus shortening the dive time because of inefficient management. 

A simple technique to check your weighting on the surface is to put the regulator in the diver's mouth. Have them fully inflate their lungs while fully deflating the BCD. A properly weighted diver will settle around the eye line in the water. If the diver exhales, they should sufficiently sink to begin their dive. A diver who is underweighted will not sink at all and a diver who is overweight will begin to sink immediately. 

If a diver has descended, there is another technique to help with determining weighting. Once on a sandy bottom, the diver can conduct a technique where they breath in and slowly rise from the bottom. Upon exhalation, they should slowly drop back down to their original position. A diver who is underweighted will begin to float to the surface upon inhalation and a diver who has too much weight will require numerous adjustments to the BCD to successfully conduct this weight check. 

Divers in Southern California typically dive with 10% of their body weight plus 4lbs (i.e. 200lbs x .10 =  20 + 4lbs = 24lbs). The human body differs from diver to diver. One diver may have more body fat than the next, or one may literally be more dense or have a smaller lung capacity. So, the guideline is a good technique for a starting point for divers, but a properly weighted diver will refine this through the above techniques. Once weighting is determined, some other minor techniques can contribute to the success of a diver in buoyancy control. 


When one goes to a race track, they expect to see streamlined vehicles zooming around at high rates of speed. The aerodynamics of the vehicle provides advantage to the racer and is something that race teams around the world pay considerable attention to be successful on the track. It's pretty rare to see a Porsche go head-to-head with a Volkswagen bus complete with surfboards and passengers. Most of the readers here can surmise who would win the race and a good deal of it has to do with streamlining. 

For the diver, the same concepts apply. Does the diver want to be the Porsche or the Bus? By tucking in loose hoses and gauges, paying attention to proper finning techniques and reducing the drag in the water, a diver will find themselves more efficient on every dive. This will also calm a diver down by allowing them to glide through the water almost effortlessly. This action of streamlining the equipment is easy to do and contribute to reduced heart rates and breathing cycles. If the diver is streamlined and calm, they'll make their scuba cylinder as efficient as possible. 


A technique that is related to streamlining and proper weighting is trim. Trim is the actual position of a diver's body in the water. Divers who sit at 45 degree angles in the water have increased the surface area of their body against the opposing forces of the water. This creates an inefficient model and resistance to the diver. Additionally, a diver who is off trim will find themselves leaning one way or the other when they attempt to relax. If the diver has to engage muscle to maintain a proper position in the water, they are basically working out instead of chilling on their dive. 

Trim is also very easy to repair for a diver. If the diver gets into their swimming position and stops moving, they will see that through relaxation their body will begin to move. If the head is going down towards the bottom, this means that there is too much weight in the torso region for the diver. This can be alleviated by shifting weights to the lower body or by moving the tank a little bit down on the bottom to provide some specific gravity in the lower region area. If the diver's legs are sinking, a weight shift might be appropriate or a change to the buoyancy of the fins. A move to the left or the right is usually an indicator that the weight is not properly distributed on the body. By tightening down straps on the BCD, shifting the tank on the back or by ensuring the weights are evenly distributed; a diver can rectify the situation. 

Regardless of the solution, a properly trimmed diver should be able to stop moving and sit relaxed in their swimming position. By doing this, they've reduced effort and conserved energy!  

Physical Fitness

The scuba world does require the human body to strap on 30-40lbs of equipment and enter the water. Propulsion is created through the fins and this also requires effort on the part of the diver. If the diver has poor eating habits, smokes or drinks heavily, or has a poor workout regime; they will struggle when it comes to buoyancy control and efficient diving. This does not mean that a diver has to be a physical specimen to dive, but it does mean that there is a noticeable impact on an active, fit diver and one who ignores these concepts to consume in excess.

Leading an active lifestyle can improve buoyancy control through increases in stamina and conditioning towards the activity. By being active and diving on a more regular basis, a scuba diver will find that things like proper weighting, trim and streamlining become much easier and make scuba diving more enjoyable. With proper diet and the shedding of habits that affect a diver's ability to effectively breath underwater, we find that the final stage of proper buoyancy is the most beneficial. Not only will you become a better scuba diver, but you may live longer and get the opportunity to enjoy the scuba life much more! 


Of all of the skills involved in the PADI Open Water program and other programs like Peak Performance Buoyancy, none can be greater than the focus on proper buoyancy control. Not only will it extend the diver's ability to stay underwater, it will preserve the environment for future generations and avoid unnecessary injuries by the defensive measures of aquatic life. 

Should you find yourself struggling with this technique, never hesitate to contact your instructor and request time in the water focusing on buoyancy control as a skill. You will be happy that you paid attention to it and you'll find follow on dives to be much better in length and focus. 

About the Author:
D.J. Mansfield
D.J. Mansfield is a PADI Course Director who dives Southern California and has done so for 22 years. He is currently the Director of Operations for Beach Cities Scuba and is a committed ocean steward and trainer for divers all over the world.

Follow him on Instagram @djmansfield7or contact him at dj@beachcitiescuba.com.   

Did you know that Beach Cities Scuba is a 100% AWARE partner? We are committed to supporting our ocean partners and creating a protected environment for sea life that includes responsible fishing practices and minimal human interaction. See how you can get involved today!

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