BuoyancyPosted: May 2, 2011
As I have promised, the first post on Buoyancy has arrived. Pretty much everyone would agree that buoyancy is one of the critical skills in diving. What does that actually mean? We spend a lot of time discussing the topic in pretty much every course, but do we ever do a good job truly getting the diver to understand what this means and what it looks like when we are good at it.
It is impossible to discuss buoyancy without discussing breathing. It is why that post came first. Buoyancy is so critically linked to how we breathe and how we change our breathing that really the two are very much linked. It is also why we need to master and understand ideal breathing for scuba prior to trying to improve our buoyancy and the control of it. Or use lung volume and where we build volume in our lungs to further refine buoyancy.
That is what caring about and paying attention to this results in, control. With control comes confidence. Ideally, each diver should be confident in their diving within appropriate development for their level of progress in training and experience. If you do not feel confident in your diving at any level, get back to the basics. It is the foundational skills discussed in my first post that will bring you the confidence and execution you desire.
So, now that you are working on ideal breathing, we can look at how we can dial in our buoyancy control. Working position is tied to buoyancy, but pure buoyancy control is what needs to be mastered first. This means that we should be able to stop at any time in our diving and not move without a change in lung volume. So, we are neutral at all times. Unless we choose not to be. It should be a choice.
There are times when you will choose not to be neutral. On the surface, we usually choose to be positively buoyant so we can rest or swim to the boat or dive site. I find I have to remind new divers and sometimes not so new divers to use their BCD on the surface to not work once their head breaks the surface of the water. It is all about minimizing work and making diving easier where we can.
We may choose to be negative on the bottom to stabilize ourself in a nonimpactable environment while taking pictures or during an experience that requires us to stay on the bottom. If I am working in a strong current and hand pulling on the bottom, I usually like to be a bit negatively buoyant as well. Most professionals while teaching use negative buoyancy to help if a new diver has a problem and the instructor needs to arrest an assent.
For the most part, as divers we want to be neutrally buoyant at all times once we leave the surface. Being neutral is the weightless inner space experience that we all as divers crave and speak to non divers about as being magic. It is one thing to know what is feels like. It is another to have such possession of it that we are able to use its control to appear to be magic.
Buoyancy changes take time to happen when we dive. This delay can be different at different times depending on depth, gear configuration and other factors. But, for the most part when we make a change in buoyancy it takes two to four seconds to really take affect. This means we can use our control of buoyancy to compensate for wave action, picking up a weight, or wanting to use ballast to drive movement along with so many other things.
It also means we have to be patient and plan for this delay in action. So, we have time to work with it, but also if we do not pay attention issues can get worse over time. This is all assuming diving open circuit scuba. Buoyancy on a rebreather is very different and not so tied to changes in lung volume as open circuit scuba. I will discuss rebreathers in future posts.
In our beginning scuba courses we are told on descent to equalize the pressure in our ears and sinuses. This is a very important thing to do as it is the most common injury for most divers if not done properly. Easily avoided if we do it early and often and before we feel anything. More on this in a future post.
However, the corrective action prescribed if there is an issue is to kick up a bit and if negative add some air to the BCD. Conversely, if someone begins to drift up a bit becoming slightly positively buoyant we say let some air out of your BCD as the first action to take.
Why not suggest that the rising diver first exhale and then emphasize breathing with a reduced lung volume or on the bottom of the breathing cycle first and then make the adjustment to the gear? Additionally, on the negatively buoyant descending diver, why not tell them to inhale and then emphasize the upper portion of the lung volume and then take corrective action with their gear?
Of course, ideal breathing needs to be mastered in order to be able to chose to deviate from it in this way. But, is it not more controllable and more intimate to use our control over our breathing first than train people to go to their gear? Going to the gear first, as almost any instructor knows in newer divers, is not quick nor familiar. I would bet that any new diver knows where their lungs are.
If we all build a strong connection between our breathing and our buoyancy we can effectively add five pounds of negative or positive buoyancy or more at will within seconds simply by how we choose to change our breathing and emphasize cycling breathing at the lower or upper end of lung volume. I am suggesting this is going to help divers feel that they have more control and I think we can all agree is more accessible, intimate and quicker than fumbling for a deflation method only to have the wrong end of the BCD facing up.
Choosing to change breathing may not solve the problem completely, but it slows everything down. It provides time for a calmer approach to finding the right item to make more adjustments to buoyancy and the perspective to think about being in the correct position to do so. Most of us have seen the newer diver facing head down trying to dump air from their BCD while swimming down fighting positive buoyancy only to have the air in the wrong place in their BCD for their attempts to be able to do anything.
If this diver were to exhale and choose to deviate from ideal breathing by cycling on the bottom of their lung volume, they would take most of that positive buoyancy out of the situation. It could bring them back to neutral or even slight negative buoyancy or at least immediately drop the urgency of the situation down several notches. This gives the diver more time to think through why what they are trying to do is not working as they had hoped it to. More time, generally means less stress and more likelihood of success in correcting the situation rather than drifting backward toward the surface.
This is only one example of how much more layered the subject of buoyancy is. It is easier to see the results in an obvious situation with a newer diver. As you get better, you will see that subtle changes in where you emphasize lung volume can play a role in trim and swimming. How you release lung volume or add it can change lift and your center of buoyancy. We can begin to use our breathing to actually help us move better through the water and also allow us to work less.
I will speak to movement and trim in future posts. Buoyancy control and working with your breathing can allow you to change how you ascend. We are taught to reach up, look up, and come up, swimming to help the movement.
What if we were to ascend by using our breathing to emphasize different areas of lung volume on average to create rises toward the surface or to drop down a bit on a safety stop or to slow our ascent and adjust our BCD? When mastered, ascents can become literally almost no work. They are also highly controlled and slow because we are intimately in touch with the movements because it all comes from our control of our breathing and our lungs. Of course, we still need to vent excess gas from our BCD or drysuit and we do not want to hold our breath.
So, buoyancy is often talked about in diving and I know that we could fill a room with instructor trainers where “good buoyancy” would make everyone’s list of important skills to master. We need to expand our understanding of what this means. We need to tie the discussion intimately to breathing and how we find ideal breathing and how we choose to change from ideal breathing if we need to do so in order to affect our control over our buoyancy.
Buoyancy control is extremely important to good diving and certainly is foundational to the Precision Diver. It just does not live in as much isolation as we have been used to dealing with it in. In the near future, I will explore how breathing and buoyancy work together in how we swim and our trim in the water as well.
The foundational skills all work together built on top of our performance mindset to hold up the roof that is performance. With performance comes confidence in our diving.