And not in a Walter White kind of way either. The Science of Diving (SSI) is a fascinating and very useful class for divers. Not all certifying agencies have this as standalone class. Many of them just incorporate the information into various other classes, especially their divemaster training. PADI has a class called Dive Theory that is roughly the equivalent.
So, what did I learn? The SSI course has five sections. If you paid attention in your Open Water class, none of these will be brand new. This course just gets into the material in a lot more depth and detail. In fact, many of the specialty classes are like that. The material is not 100% new, but more detailed.
Diving Physics
Diving physics covers the non-biological physical aspects of diving. This includes things like buoyancy, gas properties, density, and other physical characteristics of the equipment. This is important for two reasons. The primary importance is understanding what you need to stay alive and safe. Secondarily, a better understanding can make you a better diver.
On the safety issues, it enhanced my understanding of how gas works under pressure. This helps to explain things like how quickly you use up the air in your tank. Here’s a hint you use it faster the deeper you go. There is more discussion on how breathing impacts your buoyancy. Buoyancy control helps you to control yourself in the water. It also helps you to avoid damaging fragile ecosystems. Most importantly, you learn to avoid uncontrolled ascents or descents, both of which can have fatal consequences.
Being a better diver just makes diving more fun. As I have more dives where I’m in control, I’m more able to enjoy the underwater world. The dives where I’ve achieved that stick out in my mind as particularly wonderful experiences.
Diving Physiology
Your body is affected by scuba diving. The biggest areas of impact are on the cardiovascular system and the respiratory system. The cardiovascular system is impacted by gasses dissolving into the blood differently at pressure underwater than they do on the surface. The respiratory system is impacted because it’s the part of your body that is compressible. It is the most impacted by the increasing and decreasing pressures as we descend and ascend in the water.
This section is 100% about safety when diving. By understanding how your body is impacted by the choice of gas when diving and exactly how it affects your body’s systems, you can make better choices before, during, and after a dive. Based on my admittedly limited experiences in diving so far, I think that many recreational divers are very undereducated in this area and should endeavor to learn more.
Much of this physiology may be covered in a diving first aid class, but this section takes a different view on it. While this section discusses things that can go wrong, it also looks at how it goes right and how we can use that to our advantage.
Decompression Theory
If you’ve stuck with my article this long, you’re probably thinking to yourself, “Wait, we do all our diving withing the NDL or no decompression limits. Why would we care about decompression theory?” I thought the same thing until someone I was watching online who is an experienced diver made a pretty profound statement. He said, “There is no such thing as no decompression diving.”
Even when you dive within the no decompression limits, your body still goes through decompression. It happens as you slowly ascend, during your safety stop, and continues when you’re on the surface until all of the inert gasses have returned to normal surface levels in your body. The reason we call it “no decompression” diving is because we don’t need to make dedicated decompression stops.
Understanding this is 100% a safety issue. Even if you never dive below 10 meters (33 feet), you could end up having issues with decompression, if you stay down long enough or come up too fast. Having at least a minimum level of understanding of decompression theory will allow you to make better choices and be safer in the water.
Components of the Total Diving System and Accessory Equipment
We all learned basics about our gear in our open water class. But it was really basic. A fascinating thing I’ve learned in the last couple of months is that all of this cool gear that allows us the fun of diving and keeps us safe is . . . relatively new. In fact, I just learned that the first commercially produced dive computer was released to the general public when I was 12 years old. That makes me feel, well, old.
The better you know your gear, the safer and more enjoyable your diving will be. To make the correct choices for your personal diving gear (or what you rent), you have two options. You can trust your local dive shop 100%. You can make all of the decisions completely on your own. Or you can balance the two, doing your own research and combing that with input from your local dive shop to make the best choice for you personally.
Why does this matter?
We Are All Different
It matters because every one of us is different in several ways that should impact our gear choices.
We have different body types. At the time I took this class, I was 6’2″ and about 330 pounds, with broad shoulders, bad knees, a problematic left hip, shoulder problems, high blood pressure, and type 2 diabetes.
It matters because we all may choose different types of diving. My diving is primarily in lakes, in all types of weather, with a goal of doing as many lake cleanup events as possible as well as survey dives to learn about the lakes, and hopefully some spearfishing.
It matters because we all have personal preferences. In some cases, you may have two equally valid choices, the only difference being your personal preference.
To get the most enjoyment and the best safety out of your diving, you need to understand the various pieces of required and optional equipment and how it impacts your diving and your safety.
The Aquatic Environment
The last section of this course covers the various things we’ll find in the aquatic environment. This includes the water itself, currents, geological formations, man-made items, marine wildlife, terrain, and visibility.
A diver in a shallower reef area in the ocean in Thailand, for example, will encounter a much different aquatic environment than I will in Table Rock Lake in Missouri (United States). They will see visibility measured in 20 meters or more range, with warm water, and an endless variety of marine life, both plant and animal. I will not see much because visibility rarely reaches beyond 5 meters, if I’m lucky, with a short list of possible fish, almost no plant life, but probably a lot more man-made structures as the lake itself is man-made.
Conclusions
The more I learn, the more I realize how little I know. Learning some of the science behind how diving works has already helped me to be a better and safer diver. Everyone should strive for that.
