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Becoming a Scuba Diver – Taking the PADI Plunge

If carefully thought through, the risks to which people subject themselves in pursuit of pleasure can verge on the insane. Take scuba diving.1 A person out of their own free forgoes breathing the air readily around them to breathe from a pressurised underwater container. Most of us unthinkingly take the air we breathe for granted; it is all around us. Not asthmatics. Asthmatics suffer occasional terrors of suffocation and understand. So do claustrophobics. What happens if your air runs out down there? Or the delivery of air from your tank goes faulty? Every time I put on a diving mask my mind goes jumpy and I have to suppress the feeling of suffocation. It takes me five minutes to adjust. Some people can’t do it at all.

Divers at Long Beach Simonstown

Divers at Long Beach, Simonstown

With scuba there’s another danger: pressure. For every ten metres you descend the pressure increases by one atmosphere. Gases shrink quickly as you descend and expand equally quickly as you rise, according to Boyle’s law.2 This applies equally to the gases in your lungs. You can seriously rupture your lungs if you rise too quickly to the surface, which is more easily achievable than you imagine, especially if you accidentally inflate your buoyancy control unit (BCU). Lung rapture can kill you. That’s why the first rule of scuba is never to hold your breath when diving. You also have to continually equalise your internal air spaces as you descend, just as you would in an aeroplane as this can cause intense pain. You can burst an ear drum, as a friend of mine did.3 Owing to improper equalising on one of the dives, I myself had intermittent pain in my ears for two weeks and experienced fuzzy hearing at certain frequencies.4 Not nice if you love music.

Then there is decompression sickness (DCS), commonly known as the bends.5 For all practical purposes, air is comprised of 79% nitrogen and 21% oxygen. The problem with nitrogen, an inert gas we don’t use despite breathing in, is that our tissues absorb it under pressure. At a depth of 30 metres it starts having intoxicating effects. At sea level nitrogen doesn’t affect us, as the body continuously expels it. At 30m however, you breathe in four times the number of air molecules per breath as at the surface and the body absorbs this excess nitrogen.6 Your body can however release it safely if you ascend slowly to the surface. The danger if you rise too quickly is that your body cannot safely dispose of the absorbed nitrogen. The excess nitrogen forms bubbles in your blood vessels and rushes out of them, similar to the opening of a bottle of soda. This is decompression sickness. A diver affected by nitrogen narcosis has impaired judgment and coordination, which often results in foolish behaviour or a false sense of security. It may lead to panic and confusion, ratcheting up the danger levels under water. More severe symptoms include dizziness, shock, numbness, joint and limb pain, fainting, paralysis and even death.7

Other dangers of scuba diving include cold, disorientation, entanglement, boats whizzing around overhead when you’re surfacing, fatigue, dehydration, general discomfort and of course the odd scary marine creature or two that might confront you.

It was to these pleasures that my forthcoming Great Barrier Reef adventure was taking me, a magnificent ecosystem about which I had been watching documentaries since my teens. I had long since resolved to immerse myself into that mesmerising kaleidoscopic world bubbling with life forms of the most bewildering variety and my chance was now coming up. But to fully benefit from the experience I had to learn to scuba dive, to run the mill of these risks. Snorkelling limits you to the surface whereas scuba immerses you totally. To this end I register for the internationally recognised PADI open waters scuba diving course, for which I go to Deep South Scuba in Muizenberg.8

Kitted Up for the Dive

Ryan is my diving instructor, and Emma his dive master assistant. First, given the risks, I have to sign a liability release, naturally, and then complete a medical questionnaire. We sit down at a table and they mark the PADI course work I had done.9 Ryan corrects a few answers I had given. “Just to repeat”, he says, “the first rule of Scuba is never to hold your breath. The second is to quell the instinct to suddenly rise to the surface. As long as you keep breathing you’ll be fine.” I have qualms but Ryan keeps reassuring me. Like all instructors in hazard, 90% of Ryan’s job is to calm people down. We train at Long Beach in Simonstown. Cape Town diving conditions aren’t ideal. If you train here, most diving sites are comparatively hospitable. First, a competency test. I have to swim 300 metres in the sea in my wet suit, then tread water for ten minutes. The swim is easily managed but I don’t have head covering so my brain freezes. Brrrrr! After that, treading water is a doddle, as the wetsuit imparts terrific buoyancy to one.

We go underwater shortly afterwards. Ryan swims gradually in front, keeping a constant eye on me, Emma follows behind. This is diving’s famous buddy system in operation. I had learnt the 25 underwater communication signals. We first practise handling mask problems. Masks leak from time to time and you have to clear them of water so that you can see. You do this by allowing water to fully flood into it, taking a huge breath and then blowing the water clear of the mask through your nose. It’s scary, you can’t see, you’re underwater and you have to force air out through your nose, not mouth. I know two people who gave up scuba right at this stage. Next, I have to remove my mask for a minute underwater. My nose and eyes fill with cold brine, the water around me blurs but I breathe, I suck that mouthpiece for dear life, to heck with the rest. We then practice exchanging regulators underwater in case we run out of air and have to rely on a buddy’s supply. Then the big challenge: Ryan would be turning off my air supply six metres underwater so I could actually experience the sensation of being without air, at which point I would reach for his emergency regulator and breathe from it. It’s part of the training. Rationally, it’s simple. But my irrational mind takes over. It completely closes up. There’s no way I’m going to allow him to shut off the air flow from my tank so I can suffocate, so that I ca die in a watery grave. I can’t. It’s a huge mental block. I shake my head, push Ryan away and signal I want to surface. At the surface Ryan sees not fear, but terror in my eyes. Terra firma! -they plead. At this, Ryan falls into a calm-down-the-trainee routine. “You’ll be fine. Look, let’s first practice here at the surface” he says. I take time to adjust. “OK, slowly”, I demur. He gradually shuts the valve to my air tank. My breathing becomes increasingly laboured and eventually there’s nothing. Nothing. That choking sensation again. Desperation. I rip off my mouthpiece and suck False Bay clean of air. Air! This life-giving thing! Oh for life! I take fifteen minutes to regain my composure before I’m suitable bolstered to attempt the procedure underwater. And so the hard training progresses, in which I conquer barrier after barrier, most of them mental.

Going Deep

My diving instructors marshal me well over the following weeks. On one of the training dives I decide to kick off on a little jaunt while they attach a buoy to a pipe for an underwater compass training exercise. Just a few metres up and down I think. How stupid! When I look again both Ryan and Emma are on my shoulder. They had dropped everything and had immediately come for me. I get an underwater reprimand. Never dive alone, especially in bad visibility as you can easily get lost! (The visibility is not even ten metres I’d say). I am blessed with patient trainers who understand and care. With their help I eventually qualify. Hurray!

Once I had qualified I go for my first actual dive without doing skills training. No mask clearing, no orientation, no controlled breathing out to the surface, no getting in and out of a BCU (a feared drill for me that; panic-inducing and requiring major co-ordination). It is pure blissful diving, kicking out slowly, conserving energy and gliding along. Magical! We go down to ten metres for 45 minutes, an easy doddle. And what marvels do I see! Psychedelic fish in a swaying seaweed forest, starfish, a huge conical jellyfish, a giant octopus, a small shy shark in a hole, scurrying crabs, crayfish, plants and invertebrates and sea cumbers and crawling things, just as I had seen on underwater nature programs all my life. What an absorbing thrill it is to be in this soundless, weightless world of wonder, worth every inch of training I had been through.

I eventually get to the Great Barrier Reef. The Whitsundays. I have arrived. My dream. This is my chance for a dive of a lifetime. I had specifically qualified for this. I had made enquiries and had secured a dive with a company on Hamilton Island. I am now here, this is it!

Whitsundays Great Barrier Reef

Alas, because of the logistics, the power structure and the convoluted social dynamics of the catamaran I was on, through wilfulness or inconvenience, I cannot dive, only snorkel. At times, life’s like that.

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Notes:

  1. In case you frequent pub quizzes, SCUBA is an acronym standing for Self-Contained Underwater Breathing Apparatus.
  2. Robert Boyle, British physicist (1627 -1691). Yes you studied him at school. Boyle’s famous law says that at a given temperature, the product of pressure and volume of a gas is a constant (p*v = C). Otherwise stated, the volume of a gas is inversely proportional to the pressure applied to it. Thus at depth of 30m, where the pressure is 4 bars, the volume of gas will be reduced to ¼ of that on the surface. But your lungs expand to the same volume with each breath you take. So you breathe in four times the air at 30m than at the surface. It also means that the deeper you go, the shorter your air tank lasts as your breathing depletes it that much quicker, and thus the shorter your dive per canister of air. The moral of the story: if you want excitement, don’t bunk your physics classes.
  3. His ear drum burst, he felt a searing pain in his head and his mask filled with blood. He lost his sense of orientation and says the last thing he saw was his diving buddy’s eyes go very wide. The buddy luckily took him up slowly to safety. He stopped diving after that. Never, ever dive on your own.
  4. I had to see my ENT specialist about my barotrauma. His command: Equalise continually, and surface the moment you feel ear pain. He told me that some divers have to stop their careers because their Eustachian tubes narrow over time. The same goes for pilots. He told me that some hardened commercial divers even take sharpened paper clips with them on deep dives and burst their own ear drums before it happens naturally. Scuba divers figure strongly among his patients.
  5. Decompression sickness was called ‘the bends’ in the early days because severe pain in the limbs prevented sufferers from extending their joints. Different symptoms of the same cause include the ‘staggers’ and the ‘choke’, depending on where the bubbles form. These nitrogen bubbles coming out of solution cause problems such as the blocking of finer air vessels, cell death, blood clotting, deformation of tissues and even nerve degeneration. It can also trigger an inflammatory response which has a set of symptoms all of its own. The cause of the bends was established by French scientist Paul Bert in 1878. One way of curing the illness is to take the diver to a recompression chamber, an expensive operation. The solution is to always ascend slowly, and stick to safety stops at various depths for the time given in dive tables. Also, divers should avoid flying for 12 to 18 hours after a dive, as air cabin pressure is lower than one atmosphere. To prevent hypoxia, the typical equivalent effective cabin altitude in a commercial airliner, that is, the equivalent altitude having the atmospheric pressure, is kept at 2400m, a level at which most people feel no ill effect. The corresponding pressure at this altitude is 0.75 bar, or ¾ of the pressure at sea level.
  6. Depth is the huge limiting factor in diving. The deeper you go, the greater pressure you’re under, the more air you use, the less you can stay underwater and the greater your absorption of nitrogen. The purpose of diving tables is to inform divers of how long they have to remain at the surface between subsequent dives, and whether any decompression stops at certain depths are required after a deep dive in order to prevent the bends.
  7. For a more elaborate treatment of underwater human physiology see Francis Ashcroft, Life at the Extremes, the Science of Survival, Ch. 2 Life under Pressure. ISBN 006551254, copyright 2000. Other chapters include Life at the Top (the physics and physiology of altitude, in case climbing Mt Kilimanjaro is on your list), Life in the Cold etc. Really fascinating.
  8. Deep South Scuba, Physical Address: The Old Post Office, 153 Main Road, Muizenberg, 7945, Cape Town South Africa. Telephone +27(0)21 788 7616. Website: http://www.downsouthscuba.co.za. Ask to speak to Dani, she’ll organise everything. They don’t only offer accredited training, but also organise diving trips around Cape Town for out of town divers.
  9. PADI is the Professional Association of Diving Instructors. PADI is present in 183 countries and has 183000 accredited recreational diving instructors, assistant instructors and dive masters under its banner. All PADI courses are based on performance-based learning. PADI Open Waters 1 is an internationally recognised qualification. The training programme aims to get you to a safe level of diving as a beginner. It is a prescribed course in which you do theory, three pool training sessions as well as five sea dives during which you have to learn a requisite set of skills, most of which concern safety and emergency drills. PADI 1 qualifies you to dive to a depth of 18 metres. No-one should dive without doing it. I am now a proud qualified PADI Level 2 diver, ISO 24801-2! Why “Open Waters?” Open water diving is where the diver has direct access to the surface at all times. The moment you don’t have direct access to the surface, as in a cave or in a wreck, risk levels rise dramatically. It requires specialist training. Unless specifically trained, never dive into a cave, wreck or any place which closes off direct access to the surface to you.

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