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Medium Dawn Felagund of the Fountain

Dive Training Day Two: Breathing Underwater

The (Cyber) Bag of Weasels

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"About as much fun as a bag of weasels"...when I first saw this Irish adage, it made me think of the life of a writer: sometimes perilous, sometimes painful, certainly interesting. My paper journal has always been called "The Bag of Weasels." This is the Bag of Weasels' online home.

Dive Training Day Two: Breathing Underwater

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forest for the trees
X-posted to the_nautilus. I swore that I would keep my scuba post there this week, but I want to remember these experiences in my own journal, so sorry to friends of both places that put up with double-post spam! :(

Because this was my birthday weekend, it was hard to fit two chapters of work into a decent amount of time. I was up until about two on Saturday night, finishing my reading and assignments, so I was pretty beat come 7:15 and time to wake up for diving.

We did Chapter Three in the classroom and both got 100% on the chapter test. w00t!

But the highlight of this class was not to be the classroom instruction. We were to begin breathing underwater, an idea that was exciting and a little scary at the same time. It occurred to me many times this Sunday about exactly how much of scuba-diving is simply overcoming human nature. A prevailing theory in the study of specific phobias suggests that humans may have evolved the most common fears--snakes, spiders, drowning, high places--since folks who feared these things were less likely to be bitten, drowned, or fall off of cliffs. (Consider, in comparison, the number of people who are afraid of automobiles, raw hamburger meat, or guns, all of which kill many more people each year than the four I listed combined.) People are not meant to stay underwater for long periods of time. Studying how to use a dive table is in part because the body can't handle hours each day at a depth of 100 ft (33 m). And aside from physical limitations, it is psychologically daunting to be in an environment where the most natural human response--one required for life--of breathing has the power to be completely absent.

We arrived at the pool and set up our gear for the first time. We attached our regulators and buoyancy control device (BCD) hoses to our air source. We defogged our masks, and squeezed into our wetsuits and zipped on our boots. With the help of our buddies, we donned the BCD and tank, securing various straps and hitching hoses into place. We checked each other's gear. We put on our masks and fins and weights and entered the water.

Unlike the Columbia Association pool that we used for our tests, the Laurel pool does not have a shallow end. The "shallow" end is about eight feet (2.6 m) deep, so we would learn our first exercises without the comfort of being able to stand. No, we were stuck to the bottom of the pool with weights and more than a meter of water over our heads.

It's amazing how buoyant one is in a wetsuit. Because the insulating part is basically lots of little air bubbles--kind of a miniature form of bubblewrap--they are naturally buoyant. My feet kept wanting to float to the surface before I strapped them into fins because the boots are made from the same material as the suits and so are buoyant as well.

Obviously, this changes once the weight is added. Put a metal can of air on your back and ten pounds of weight around your waist, and you'll sink in a hurry.

Bill (the instructor) had us inflate our BCDs to stay comfortably on the surface, put the regulators in our mouths, and stick our faces underwater. We were breathing underwater. Like fish. I kept waiting for it to feel wrong or different, to not get adequate air or for something to go wrong. I will admit that I swallowed a lot of air in those first few minutes from anxiety alone that came back to torment me later. (I cannot burp "naturally" and have to gag myself forcibly in order to get the air out. Yuck.)

For our first exercise, we were to swim across the pool on the surface, exchanging our snorkels for regulators every few breaths and vice versa. This first week's exercises involved a lot of removing the regulator while underwater, which is a scary prospect. It is not something people like to naturally do, to remove their only air source while stuck at the bottom of an eight-foot pool.

But that was part of the point, I realized. This first week's exercises dealt a lot with overcoming divers' psychology, i.e. natural tendency to freak out. They don't say as much, but I believe that this is true.

When we reached the "shallow" end, we deflated our BCDs and knelt on the bottom of the pool. We would not surface again for more than an hour. Bill had explained the hand signs that he would use at various points, and we started the exercises. The first thing that we were expected to do was an arm sweep for a lost regulator recovery.

Okay, so I've been in the water for five minutes, and you want me to take my air out of my mouth, throw it aside, and attempt to find it with six feet of water still over my head?

But this is what I mean when I say that I believe that so much of this training is oriented more toward psychology than anything else. I think that everyone's worst fear at this point was losing our regulators. We don't yet know how to breathe off our buddy's octopus (extra regulator), and we're not even comfortable enough with our buoyancy to assure a fast exit to the surface. But recovering a lost regulator is easy: sweep your right arm straight back along your right hip, stretch the arm to the side, and bring it forward. Guess what? Your regulator is caught on your arm.

And so our worst fear was assuaged: No matter what happened, we would be able to recover our regulators.

Next, we practiced mask clearing. Again, this is something that is fairly easy: Press the top of the mask to the forehead and blow hard through the nose. All of the water bubbles out the bottom. I've been doing this while swimming, since I swim with my mask and it sometimes gets filled with water, and I don't like to stop to take it off, empty it, and put it back on. Again, this was pretty easy.

We practiced signaling to our buddies to share air, detaching the octopus, exchanging it for the regulator, and preparing for an ascent. Again, this involved removing the regulator while underwater, but we were becoming practiced at this by now, and it was far less scary.

We practiced disassembling the BCD air hose underwater and also orally inflating the BCD. (It is usually filled with air from the tank, but in an instance where one has no air in the tank, oral inflation is required.) By far, the most difficult exercise was breathing without the mask on, then replacing and clearing the mask underwater. The bubbles from my regulator went straight up my nose, and a good deal shot back to my throat. It was not comfortable, and it was tempting to give into panic. I had to talk myself through it. Breathe, you have an air source. Exhale through the nose and try to clear the worst of the water. Then Bill signalled to put my mask back on and I was glad...even if it was filled with water!

We practiced swimming underwater from the shallow end to the deep water at thirteen feet. We did fin-tip pivots, which involve lying flat on the pool bottom and inhaling to lift the body up and exhaling to lower it back down. It is an exercise designed to illustrate how lung volume affect buoyancy. For me--being as my lungs could be donated as dirigibles, I think!--if I took a full breath, I could practically lift myself into a standing position. This means that I will be able to control my buoyancy a good deal by controlling my breathing...but also that I will have to be aware of my breathing and how taking deep lungfuls of air might keep me off the bottom (as it was doing!)

Bill advised us to think mentally on each exercise this week, and I think that this is a wonderful idea. Because I persist in believing that scuba is not physically challenging--not at the level we are, anyway--but more a mind game with oneself. When I started, I was nervous. I swallowed a lot of air. I was hypervigilant, believing that every blip in my breathing meant that I was going to lose air.

At one point, I realized that I needed to relax. I calmed and concentrated on my breathing. I realized that breathing from a regulator is no different than breathing regular air--except it makes your mouth dry much faster! And everything that I did: THINK. Think first before acting, before allowing the body's natural tendency to "Surface!" to take over. Most scuba dilemmas have easy solutions; decades of divers have perfected every aspect of the equipment to be idiot-proof. Recovering a regulator or using an octopus is the same no matter what type of equipment that you use. You only have to stop and think--not panic--about how to use it. Trust your equipment but, most of all, trust yourself to be able to respond properly even if the equipment fails.

I learned more about myself in an hour-and-a-half at the bottom of the pool than I do in a normal month.
  • Wow! and that's all still in a pool! How do you get back to the surface with the weights holding you down?
    • The buoyancy control device (BCD) is basically a big inflatable vest that attaches to the tank (or can be blown up orally, as we had to do). When a diver goes to the bottom, the BCD is deflated. When you inflate it again, you pop right back to the top like a balloon!
  • Ahh, you've elucidated the nose thing for me a bit. I know I can't swim under water without accidentally sucking water up my nose, and I was wondering how you can scuba and breathe if your nose is in the water. Now I infer that it's in the mask with your eyes?
    • Yep, scuba can't be done without a mask that encloses the nose, though not because the water gets in your nose (though, for comfort, that's a big reason too!) Actually, we will have to swim a ways without our masks in a later lesson. I'm hoping to practice mask removal a bit before then and learn how to keep the bubbles out of my nose!

      But the reason for needing the nose inside the mask actually has to do with equalization, or keeping the pressure the same inside and outside. As you go deeper and the pressure increases, the mask will press into your face. Small capillaries around the nose burst and fill the mask with blood. Yuck.

      To keep this from happening, we equalize every few feet, holding our noses and blowing to keep our ears equalized and also blowing through our noses into our masks to keep from experiencing "mask squeeze." With just goggles covering the eyes, there's no way to equalize and you end up coming up looking like Little Mack in that old Punch-Out Nintendo game. :^P

      There's your diving lesson for the day. Quiz next week. ;)
  • Okay I gotta ask... how much weight on the belt does it take to make you sink? And I was wondering how long a body can handle being under water?

    • Okay I gotta ask... how much weight on the belt does it take to make you sink?

      It depends on a lot of things: the particular diver (if she is small like me or huge like Bobby, for example), the kind of exposure suit (since wetsuits make you float), and the type of water (since salt water is denser and makes a person far more buoyant). Right now, weighing 140 lb/64 kg and wearing a wetsuit top in fresh water, I wear 10 lb/4.5 kg of weight on my weight belt.

      And I was wondering how long a body can handle being under water?

      That depends on the depth because of the pressure. At high depths/pressures, nitrogen levels in the blood begin to increase and can be dangerous if too long is spent at those depths. So if I am diving to 100 ft/30 m and you are staying relatively shallow at 35 ft/11 m, you can stand to stay under much longer than me (roughly three times as long, iirc).

      If you stay shallow, as in diving in a swimming pool (as we've been doing), you can stay under until you run out of air! :) (Which varies from person to person. I probably could have stayed under about two hours on Sunday, but we all come up when one person runs low on air. Women tend to use air much slower so we get the short end of the stick when diving with men! :^P)
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