When discussing buoyancy control, divers are actually talking about two critical skills. The first is the act of hovering and the second is the coveted "trim" we often hear from experienced bubble blowers. Both of these techniques are essential in achieving excellent buoyancy control. 

Divers want to stay off the bottom. The act of achieving a hover helps accomplish this for a number of reasons. Divers do not want to damage the ocean any further than it is currently impacted by human interaction. A fin kick to a 200-year old piece of coral or the crashing of a human body into a beautiful gorgonian can create a ripple effect that destroys much more than the initial impact. Additionally, when a diver is in the water column and in a comfortable hover position, they are at their most relaxed. A comfortably chill diver will save a ton of air by maintaining perfect control on their dive. Most divers will notice this as they dive more often. Their first dives will be 20-30 minutes and slowly, they'll experience that the same tank is providing them with more time underwater. This is because they are relaxed and capable of smoothly moving through the water column. 

How do we achieve neutral buoyancy? It's actually quite simple. A diver who achieves neutral buoyancy correctly will not require much movement to move around underwater. There are numerous methods to check our weighting first. Having the correct amount of weight (and correct placement) will spell success to a diver. In the Open Water course, we learn that our body will displace water equal or greater to the amount of water that it sits in. Which is why most people float. We counteract this resistance by adding weight to our equipment. This weight coupled with a buoyancy control device (BCD) will guarantee success in the water. A diver can sit at the surface of the water and conduct a buoyancy check. This helps determine the correct amount of weight. With the regulator in the mouth, the diver can empty the BCD fully. As you begin to sink, take a full breath of air into the lungs. The diver should settle at the water line where their mask is located. If the diver does not move further down, it means that they do not have enough weight on their body. If the diver sinks to the bottom like a rock, that means that they have too much weight on. Why does that matter? 

Too much weight will turn a relaxing dive into a workout. As the diver is dealing with the adding resistance, they will find themselves breathing harder and losing the ability to be underwater for a longer period of time due to air consumption. If the diver does not have enough weight on, they will not be able to sink. If the diver can get below the waves, they will have trouble staying down. Which means more swimming, more exercise...you get the point. 

Now that we've determined that we have the correct amount of weight on our bodies, we can descend. There are two methods of achieving neutral buoyancy underwater. The first was previously known as the fin pivot. This was a check underwater to start the dive. The intent was that the diver could control their buoyancy through the act of breathing. As our training organizations have advanced their skills, we now do this skill from a neutrally buoyant position and display it by slowly breathing in and out to show that we are controlling our vertical position in the water column by breathing in and out. Instructors used to say that it was like doing push-ups without arms. The diver was able to effectively control their buoyancy and the hope was that divers would realize that they did not need to use their BCD for every single adjustment on a dive. For example, maybe the diver is cruising along and encounters a large rock. A neutrally buoyant diver can breath in slightly and make the body rise. As the diver goes over the rock, they let that air capacity out of their lungs and slowly descend into the original position. 

The pinnacle of buoyancy control is the actual act of hovering. Hovering reveals certain things about the diver. First, it is lung control. When hovering, a diver is not breathing heavily in and out. Doing so, will make a neutrally buoyant diver shift the vertical position drastically. A diver who can control this will settle in the water and maintain position. It is also a challenge to actual movement. Divers who are swinging their arms or constantly moving their legs will not achieve a proper hover. The diver should be able to sit comfortably in position without movement. This displays that buoyancy control is achieved. A hovering diver will also reveal the second part of a successful skill, which is trim control. 

If a diver is falling backwards, sitting on their side, canted to one side, etc.; they reveal that the weighting is incorrectly positioned. It does not sound like a big deal for a diver to deal with off kilter weights, but it is. If there's too much weight on one side versus the other, the diver will have to compensate that effort through muscle engagement. Though we are in a weightless environment, we are still able to use muscles to maintain balance. Imagine doing an hour of planks underwater. This expends energy and results in a diver who is wasting air because they are too busy trying to maintain a balance in the water. This can be overcome through a proper hover scenario in a pool. The diver can make weight changes by shifting weights, moving them to different positions on the body or by using video recordings to see how the body is performing while diving. 

Once the diver has achieved proper weighting, proper buoyancy and proper trim, they can begin work on the final skill. This is known as streamlining. 

Streamlining is the conscious act of ensuring hoses, materials, swimming position and kicking of the fins are as efficient as possible. The low pressure inflator hose, the submersible pressure gauge and the regulators should be streamlined to the body. A dangling SPG, for example, can create drag or possibly become an entanglement hazard. By tucking this item in to an area of the body that it can be accessed easily, but also not create drag will ensure a more efficient diver. The diver who is neutrally buoyant will not be on the ground, they will be a few feet above and enjoying the weightlessness that all divers love. Finally, the efficient fin kick will then complete the perfect diver. By generating the power from the hips and keeping the knees as engaged as possible, a diver will glide through the resistance of water and not be tired at all while moving quickly through the water.   

A diver who is neutrally buoyant and properly trimmed will result in relaxation. From there, they can work on gliding through the water slowly and surely with those beautiful fins on their feet. Divers will then experience longer dives and find themselves enjoying the dive much more because they aren't associating a dive with work.

With these techniques, you can begin working on achieving neutral buoyancy and body positioning that will ensure your success. If you are interested in learning more about this act, it is a great idea to sign up for the Peak Performance Buoyancy program. This is a fun course that challenges divers to work on the skills that will result in superior buoyancy control. After a pool session, the diver will go out to accomplish two dives in the ocean where they will continue to hone their capabilities as a diver.

Get out there and dive today!

Did you know 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!

Further Reading! Lonne, Torben 2023. https://www.divein.com/diving/buoyancy-control/

Introduction

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. 

Streamlining

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. 

Trim

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! 

Conclusion

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. 

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!