ErwinJA's SCUBA FAQ

Jul 29, 2016 8:40 PM

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Dec 2007

2698

I said I was going to do this, didn't I? It actually took several days for me to determine this was how I wanted to provide the relevant information, but I think this format is best suited for the wide variety of things you might want to know.

Now please note, I only have modest training and experience as a diver. But that's probably more than most viewers of the show. And this will provide you not only fun and interesting information that the show might pass over or cover inadequately, but also help you determine if maybe you want to dive to. So, without further ado:

What is SCUBA?

Do I Need a Certification or Something to Dive?

Then, How Do I Get a Certification?

There are well over 200 agencies and organizations that train and certify divers. The standards, including testing, definitions for levels of proficiency, and benefits of certification can vary from one organization to the next (though there are ISO standards). Many are also national or regional (or specialized), and won't serve you well if you travel outside their region, though you may be able to "transfer" a certification. Of course, it's usually better to just get one from a widely supported organization to begin with.
Of those that are truly international, the largest, and the one that I was certified under, is the Professional Association of Diving Instructors (PADI). PADI has four main levels of certification:

1) Open Water Diver: the international standard for beginner level. You'll have basic skills, with a recommended maximum depth of 18 m/60 ft. However, most recommended restrictions are just that, and specific conditions (currents, visibility, temperature, hazards, etc) may raise or lower the depth you're able to safely go.
2) Advanced Open Water Diver: a more advanced level that includes a handful of required specialty courses (underwater navigation, deep diving), and at least 3 of over two dozen additional specialty courses. These include unique types of dives like wreck and night diving, as well as technical and equipment oriented courses (oh look, dry suits). The maximum recommended depth increases to 30-39 m (100-130 ft).
3) Rescue Diver: adds stress management and skills to help both oneself and others in the advent of an emergency. You're now a SCUBA lifeguard!
4) Master Diver: this is more a recognition of knowledge and experience than a course itself, and requires Rescue Divier, 5 additional electives, and at least 50 logged dives.

Note that I never went beyond Open Water Diver, as I typically dive in reefs and coastal areas where the depth is only about 6-12 m (20-40 ft). I have, however, considered the wreck and night diving courses, both of which can open one up to some spectacular sights. Technically, I don't need them to do that kind of diving, but they certainly help, and again, many establishments won't let me do those things without the course.

There Are Tests, Aren't There?

How Long Does a Certification Last?

Are There Age Restrictions?

Are There Any Conditions That Can Stop Me From Diving?

There are a number of things that can render you temporarily unable to dive safely. Excluding voluntary ones like intoxication, the most common issue comes from ear and sinus infections. The pathway from your nose to your middle ear (Eustachian tube, for the record), which is the key to equalizing pressure, includes mucous-producing membranes just like your nose, as do parts of the ear themselves. If they're clogged, or even just have restricted airflow, you may not be able to equalize, and therefore have to abort any dives. A range of other conditions affecting the Eustachian tube and middle ear can have similar effects. Most of these can usually be cleared with medication. But, if you use that solution, make sure that it's going to last long enough, and not going to cause unwanted side effects.

Another issue is dehydration. While diving, you are breathing very dry air, and your mouth, throat, and nasal passages in particular will dry out very quickly as a result. Especially if you already have issues to that extent (like me), this can cause your body to start . . . producing mucous. The result is congestion, which we already said leads to equalization problems. And we're back to sitting out the dive. As such, drink plenty of water before and after diving. It also might be good to have a lozenge, hard candy, or other mechanism to soothe your throat handy just in case it starts bothering you.

There are also more permanent issues. Some people have asymmetrical middle ears and/or Eustachian tubes. This results in pressure changes affecting the individual ears unequally. And just because they had to be important, these affected areas govern your sense of balance. Unequal balance mechanisms, as you might expect, are bad. People with this condition who go through rapid pressure changes associated with diving (and flying) suffer from what is known as alternobaric vertigo. Like other forms of vertigo, it's characterized by extreme dizziness, disorientation, and even nausea. Obviously, it's quite dangerous to feel like that in a diving situation. And even if it wasn't, who'd want to dive if it made them feel like crap?

A middle road occurs in a number of (usually) correctable, but nonetheless difficult-to-overcome problems. All of these are related to long-term issues with the Eustachian tubes and/or middle ears. Scarring from frequent ear infections (usually during childhood) can do this. As can any number of ideosynchracies in the important areas. All result in the same basic issue: inability to equalize. This often cannot be solved by trying alternative methods (there are actually dozens, but most are variations on the big 3 introduced in episode 3). However, many problems can be fixed in the medium to long term (it can take months) by "exercise" regimens performed regularly over an extended period. Still, some are caused by permanent damage or deformity that nothing short of surgery will fix. And in some cases, not even that. Such people, just like those with vertigo, are simply out of luck. But, they can still snorkel.

How Long Do Dives Last?

How Deep Can I go?

How Often Should I Equalize?

More will be coming, but this should be a good start.

ErwinJAJul 29, 2016 9:26 PM

Jul 30, 2016 3:37 PM

Bobby2Hands

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Dec 2015

7387

Well this certainly was a comprehensive guide to SCUBA diving.
The only question I have left is, does diving require a lot of mouth breathing?

Sep 1, 2016 5:28 PM

ScapaFlow47

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Dec 2013

120

EW PADI.... NAUI all the way

Decent Post btw

Sep 2, 2016 4:22 AM

ErwinJA

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Dec 2007

2698

ScapaFlow47 said:
EW PADI.... NAUI all the way

Decent Post btw

Blame my mother. I was a minor at the time and she's the one who set it up. I've been dealing with the fallout from that decision for nearly 20 years. :P

But seriously, there's not much wrong with PADI's instruction that I see. What bad rep it has is mainly due to contempt for its higher commercialization compared to many other similar organizations. But as a result of that, it also has many benefits the other groups wish they could get. And many of those help its customers too. In fact, my certification came through a program run by a non-profit that had partnered with PADI.

Bobby2Hands said:
The only question I have left is, does diving require a lot of mouth breathing?

I would have assumed that to be fairly self-evident, but it's my policy to assume any post that doesn't explicitly indicate being unserious is serious. So:

So, what's this "mask clearing?"

This is a fix for a common issue. Divers' masks create a seal between their rubber or silicone edges and your face. However, even a slight facial contortion, a tiny hair, or any number of other things (like something hitting the mask or strap) can create a break that allows water in. Therefore, it's not uncommon for the water-tight seal that's supposed to be there to spring at least a minor leak - as happened to Teko on her first dive. We men also have to contend with this added obstacle known as facial hair, which, even with a shave, can still break seals all on its own.

Naturally, if the seal is broken while you're down there, you get water in your mask. This can irritate your eyes and (more importantly) get up your nose, two things you don't want in the middle of a dive. Mask clearing is a (relatively) simple technique to flush the water out. The basics of the technique are that you take a deep breath, hold the top of your mask firmly to your forehead, tilt your head back, and breathe out forcefully through your nose for a few seconds. Basic physics does the rest. For most, that's all you need to do, though some people can't muster enough force in their breath and may need to lift the bottom of the mask just enough to break the seal, reducing the force needed.

Oh, and by the way, letting a little water in, swishing it around, and then performing a mask clearing is the standard means of dealing with a mask fogging up, which is another fairly common problem. And, of course, if the mask gets knocked off, you're obviously going to be doing a mask clearing after putting it back on.

Of course, there's an old saying: "The important things are always simple. The simple things are always hard." While the technique itself is simple, many people have problems doing it because of the sensations involved prompting them to react in the wrong way, and then panic. In addition to the tendency of some to panic, there is also a strong natural tendency to try and breathe in through the nose since you're using it to breathe out. This can get water into the nose (and possibly lungs), leading to all sorts of unwanted things. A host of other issues also exist. Nonetheless, mask clearing is a mandatory skill for any certification, and one of the most common hurdles that prospective divers run into. It's basically the parallel parking of dive exams.

What is neutral buoyancy? And why is it important?

So, how do I control my buoyancy?

Well, the first thing to realize is that both your body and key pieces of equipment already have a slightly positive buoyancy. The second is that there is no point in the dive you want to be that way. Plus, once you're underwater, it's easier to increase buoyancy than it is to reduce it. As such, divers want their buoyancy to be slightly negative from the start, and then increase it as needed.

Now, buoyancy is a function of surface area versus weight (in other words, density). Neutral buoyancy occurs when the weight of an object is equal to that of the water it displaces. So, an obvious way to reduce buoyancy is to add weight. Thus, we have nifty little belts with multiple sealed pouches we can stick heavy weights in (appropriately called weight belts). Divers thus adjust their buoyancy even before the dive starts by choosing the number and size of the weights.

And to increase buoyancy while underwater, we have this wonderful thing called a BCD (Buoyancy Control/Compensation Device). This is basically a life vest with air pockets that can be filled or emptied as needed - usually from the tank, but with a mouthpiece as backup. Now, all you really need to know is that putting air into the BCD increases buoyancy, while taking air out reduces it. This works because filling those air pockets blows them up like balloons, increasing our surface area and thus reducing our density.

Do note that, due to the effects of pressure, buoyancy only holds steady at a given depth, and adjustments have to be made as your depth changes. On the other hand, you can also have some fun with it. Your lungs themselves act as a mini-BCD, especially with deep breaths, allowing some neat tricks. One is to take a sitting position, and use your breathing to rise and fall slightly without doing anything else. A similar one, and how my instructor had us show we could attain neutral buoyancy, is to lie on the bottom, and do pseudo-push-ups just with your breathing.

Oh, and once you're back on the surface, you're free to inflate your BCD to a strongly positive buoyancy and have it act like an actual life vest for a few minutes. A great way to relax before getting out of the water, or get something out of an otherwise aborted dive.

How do I know when it's time to surface?

How do I communicate underwater?

ErwinJASep 3, 2016 1:22 AM

Sep 2, 2016 4:31 AM

ScapaFlow47

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Dec 2013

120

Honestly it was a joke, I know some Divers really get into it but it honestly dose't matter. Its all about who you get as an instructor because unfortunately some dive masters are as incompetent as the students they teach.

Sep 3, 2016 1:24 AM

ErwinJA

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Dec 2007

2698

ScapaFlow47 said:
Honestly it was a joke, I know some Divers really get into it but it honestly dose't matter. Its all about who you get as an instructor because unfortunately some dive masters are as incompetent as the students they teach.

No worries. I've never taken the flak seriously, despite having gotten quite a bit of it. The first part of my response should have indicated I fully understood the intent. It was just that this is a thread for people who don't know diving, so I want to be careful about giving wrong impressions.

Sep 20, 2016 7:23 PM

Josh

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Mar 2012

17649

Very interesting. Thanks for putting that post together, Erwin.

LoneWolf said:
@Josh makes me sad to call myself Canadian.

Oct 13, 2021 7:23 AM

jpb18

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Nov 2020

ScapaFlow47 said:
EW PADI.... NAUI all the way

Decent Post btw

Ewww PADI, NAUI... SSI all the way!

Loved the FAQ though. Only thing that I think its missing is a segment about DCS, but since the show hasn't touched that subject, it's just a nitpick (even though the fin dude on episode 12 may have had issues with that).

Now to the outsiders, there's this kind of informal joke where we diss the certification agency where our fellow divers take their certification. But its mostly done as a joke and shouldn't be taken seriously. Most agencies are compatible with each other since most of them follow the WRSTC (World Recreational Scuba Training Council) guidelines. Most differences tend to relate with internal protocols. For example, PADI instructors must instruct exactly the content of a certain course, and are forbidden from 'overteaching', even if it may benefit the trainee diver. SSI on the other hand allows that flexibility to their instructors, as long as the base line for the course is taught. (I don't know how the other agencies handle that)

The only practical difference I remember is the protocol for air sharing. PADI instructors teach that the diver who's out of air should reach for his partners alternative air source (after signalling of course). SSI instructors teach that the partner with air should give his primary source to his buddy, and after that, calmly grab his own alternate. They're both valid methods with their own valid reasoning, even though I prefer SSIs method.

Remember that 'overteaching' part? My instructor actually taught how to share air using both methods. A PADI instructor is contractually forbidden of doing that.

But as any future diver should be noticing, those diferences are mostly nitpicks, and all agencies are capable of forming competent divers, and then experience when diving does the rest =)

jpb18Oct 13, 2021 7:28 AM

Aug 29, 2023 10:38 AM

Gyarutsundere

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Mar 2010

5223

jpb18 said:

ScapaFlow47 said:
EW PADI.... NAUI all the way

Decent Post btw

OH learned something new there. Always wondered what the differences are. Here there's mainly padi but there's also ssi. Never heard of naui here tho.
And it's true about the method they teach when out of breath. I learned 5 ways but each was for a different situation. If buddy is nearby however yeah you use their secondary breather/air provider. Unless you still have some of your own left, but not much, and are at 9m or less

------
I tried diving myself with padi but well I gave up after joining 2 groups I didn't feel like I was competent enough. Did pass the written test tho. Did a medical check but that wasn't the issue either, even if I had a hard time clearing my ears. Had 3 instructors so yeah...

Maybe it's their teaching style and I could give ssi a chance. My bf has ssi certification. Or maybe it's my anxiety and fear of failure, I could totally relate to teto imho.

An intro dive ive done several times now and I was totally OK there ^^ was fun too and at least I can use my mask and fins for that plus snorkeling. ^^
Just feel I put in a lot of money and now miss out on diving on my own tho :( but can recommend to everyone to at least try it out :) even if it seems scary, at the very least you can always do intro dives :D where they pretty much babysit you XD but you see so much beauty even if you don't go below 6m

GyarutsundereAug 29, 2023 10:44 AM

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