After the fitness tests, we learned how to set up the tank, buoyancy compensator, regulator, and weights. Each of these takes some explaining and I’m going to go through that, so you’ll know what to expect.
Tanks
The standard scuba diving tank is 80 cubic feet. It’s a cylinder that’s around 7.25 inches in diameter and about 26 inches tall. They weigh about 30 pounds when empty and around 50 pounds when full. They can be made of a few different materials but the most common material for recreational divers is aluminum. There is a valve at the top and there are two types of valve connections. DIN is used outside of the US. Most valves in the US are what is called a yoke system.
The tanks are usually filled to around 3000 psi (pounds per square inch) which is equivalent to about 206 bar. That’s a lot of pressure. You do not want the valve at the top to get knocked off. The results of releasing that much pressure would be . . . bad. The tanks are sturdy and can last years with good maintenance but treat them well.
Buoyancy Compensator (BC)
The buoyancy compensator (BC) or buoyancy compensation device (BCD) is sort of like a backpack or jacket you wear that serves a few purposes. One purpose is to attach the tank to something that is attached to you. The second is to provide various spots to attach stuff you might need to have with you. The third purpose, and the one that gives the BC it’s name, is to allow you to adjust your buoyancy in the water.
The BC achieves this buoyancy adjustment by way of a bladder that can hold air. This bladder comes in a couple of different styles that are related to where that air bladder is on your body. Back inflated ones have the air bladder all at your back and jacket style BCs have the bladder come around your sides a bit. A hose from the regulator connects to an inflator/deflator control on the BCs so you can add or remove air as needed to adjust your buoyancy. BCs have a rating for how many pounds of life they can provide in the water when full of air.
Regulator
This is the most important section and the one I’ll spend the most time and detail on. The regulator is the device (or devices) that let you breathe underwater. That makes it the single most important part of your gear. If you mess this one up, the best case is you make a quick end of your dive. Worst case, you die.
Regulator – First Stage
A first stage regulator attaches directly to the tank. The purpose of the first stage regulator is to take that air at 3000 psi and reduce the pressure to something more manageable by the rest of the system, usually in the range of 110 to 140 psi.
That first stage regulator may have multiple ports on it. The ports are labeled as HP (high pressure) ports and either LP or MP (low or medium pressure) ports depending on the manufacturer. They will usually have one or two HP ports and anywhere from four to six LP ports. The HP ports are to connect gauges or wireless transmitters to measure the current tank pressure, so the HP ports are the full pressure of the tank. The LP ports are for everything else, including the primary 2nd stage regulator, an octopus (a backup to your primary regulator), a hose to the BC to use for inflating it, a dry suit, and possibly other accessories.
Regulator – Second Stage
The second stage regulator (primary and/or octopus) further reduces the pressure to whatever the ambient pressure is where you are breathing. If you are on the surface at one atmosphere, it would come out at one atmosphere. If you were 10 meters down, the pressure would be two atmospheres. One atmosphere is about 14.7 psi.
There are a lot of features to regulators. These are all designed for various purposes in diving as well as convenience and enhanced safety in different conditions. Manufacturers design some regulators to work in cold water if you’re diving someplace like the Great Lakes or in Canada. Some have adjustments to help with ease of breathing to customize it to your personal needs. A regulator can steer bubbles away from your face, a feature many photographers like.
Weights
Most modern BCs have integrated weight belts. Why? In fact, you may think, “wait a minute, weights?” Yes, weights. Because without them, you won’t sink enough. My first time in the water with all the scuba gear on, I had to have 16 pounds of weights to be able to dive. With a wet suit, I needed 26 pounds. I have been able to reduce that amount considerably as I’ve done a few more dives, but it is still needed.
Conclusion
For all the complexity, getting this stuff set up was not very hard and now, after only 11 dives, I can do it fairly quickly including running down a checklist of everything to ensure it’s all working properly.
