Looking for some opinions of Instructors and Tech divers please

[mmimadi]

Hello! Im hoping I could ask the instructors/tech divers in this group about something,
Im doing a project and my topic asks, is scuba diving at 100 feet any more dangerous/risky than diving at 60 feet? (OW max depth and AOW max depth)
I would love if you are an instructor or tech dive(or whatever) and could chime in with what your stance on this is, and part take in my project. Please leave your cert and your cert number. I dont have to quote you if like, or I can, whatever you prefer. I would just like to hear what your stance on this.
Thanks for taking part!

 

[Scuba Legends]

Hy Mimimadi,

Well your question sounds simple, but it is not.

Has too many specifications to be answered. I will do my best as far as my knowledge allows.

I would like to start saying that there is nothing that makes diving at a 100ft less risky than a 60ft.

I would also like to say that with the correct training and knowledge and of course common sense i would say that it is not more risky, but there are a few more things to be considered and taken care of.

Lets take a quick view on what it should be said...

Air consumption:

Well obviously, due to the depth,for the same period of time, you are gonna be using more air at a depth of 100ft than at a depth of 60... 40% more. We could say that is more likely to run into an out of air situation. But this can be avoided very easy by checking often your air gauge and briefing with your buddy a pressure where is time to go back up.

NDL:


One limit on your dive that you start considering seriously when diving deep is the No Deco Limit. Not only at this particular dive but on the consecutive dives of the day even though they might be shallow. So if you don´t take care of that you might run into deco, witch is something a Recreational diver should (I say should because is not uncommon) never do. So as we learn in the OWD course running into deco has its dangers.

Narcosis:

You´ll experience narcosis if you cross the 30m depth. If you never experience it you might end up in troubles, so you better choose an experienced diver that has plenty of deep dives otherwise the two of you could end up doing something really stupid and dangerouse

Oxigen Toxicity

Even though we are talking about depths that are far away from this risk, at the moment you decide to dive Nitrox, the Oxigen toxicity becomes a real Risk.

Buoyancy

I add buoyancy in this list even though i consider it vital for any dive at any depth. But, multiple accidents happen, including in the Advanced training you mentioned, due to massive over-weighting.

You can read one of my articles about this problem:

The bad habit of overweighting


Now I would like to tell you my pint of view.

Its all about common sense.

Under my point of view lack of common sense makes diving dangerous at any depth. Under my point of view, a diver that knows and understand the risks and dives under the basic rules at a depth of 30m is more safe that a diver that doesn´t know what i doing at 18m.

When something goes wrong at a depth, one thing that will decide how it will end up is your experience and capacity to remain calm and think. But the other thing that will make a difference is how have you been managing your dive.

If, for example you separate from your buddy because you want to take a nice picture from a clown fish, and never nothing happens, well is ok. The day you have a free flow regulator or you run out of air, you´ll regret to have taken that decision.

I would say that Depth (Recreational Diving depth) requires more procedures, more understanding and more common sense (more training if you rather). But if you follow that i would say it is not more risky. Some things can go wrong, and if they do, they can be much worst at a depth, but we train the divers to solve those situations (at least i do) and on top of that, we train them to avoid them.

So i am not sure if i clarify your question, but like i say always, in diving you will rarely find a unique answer for a topic. Wait a bit and you will see how many different answers and oppinions (most of them for sure valids) you´ll get from this post.

Happy to help, please quote me it would make me really happy

Happy Bubbles

Gery #scubalegnds

http://www.scubalegends.wordpress.com

http://www.facebook.com/scubalegends

 

[tbone1004]

Disclaimer, I'm a NAUI instructor so we don't have the same depth rules, our OW divers are limited to 130ft. Obviously not during training, but I don't believe PADI actually restricts certified divers to 60ft. It's a strange gray area....

Air consumption is the big one. We'll use "easy" numbers, so 60ft is 3ata, 100ft is 4ata. You are using air 30% faster at 100ft than you are at 60ft. That is not a factor to be taken lightly, especially when doing gas planning. Most divers grossly underestimate the gas required to properly analyze, fix, and recover from a situation underwater and don't plan their gas accordingly. They'll blindly follow "back on the boat at 700psi" or whatever nonsense they were taught but don't know how to apply that to other tank sizes or why it came about in the first place.

I don't think the NDL risks are any more serious than at 60ft, and if using nitrox, most divers will still be gas limited if they abide by rock bottom. I utterly hate when instructors say violating NDL's are dangerous. It instills bad feelings for divers and it becomes a scary place and then DAN gets called because they think they got bent because they violated NDL's. Likely all it will do is change your safety stop from optional to mandatory, and if diving a computer, odds are you are going to clear it on the way up anyway.

Narc, you are definitely not guaranteed to feel a narc at 100ft. Depending on the water conditions and your susceptibility to it, you may, but it is unlikely in normal recreational environments. Cold dark water, probably, clear warm water? I doubt it. I get narc'd easily, and in a cave I can feel it on EAN32 at 4 ish ata. In OW, I can't.

we'll have to disagree on oxtox since recreational nitrox limits of EAN40, while not ideal, aren't going to be toxic at 100ft. and I don't think I've ever seen an EAN40 fill. It's the limit because of O2 cleaning and realistically isn't that useful of a mix. EAN36 is a common mix, but I've never seen intentional fills higher than that outside of decompression cylinders.

Buoyancy we'll have to disagree with too because the risk of overweighting imho is far worse in the shallows because of the pressure swing. There is almost no pressure swing between 3-4ata when you change even 5ft of depth, vs being overweight in 20ft and that bubble that is way to big because WAY too big and then you shoot to the surface. That becomes an embolism risk and is much more pronounced when at the surface. Doesn't mean overweighting is good, but I think it's more bad when diving shallow.

So realistically, if you trained your OW students properly, I don't believe there are any measurably more risks diving at 4ata than there are at 3. They have to plan their dive and dive their plan with emphasis on rock bottom calculations and make sure to abide by NDL's. If they do that, then there I don't think there are inherently any more risks to it.

 

[Diver0001]

Hello! Im hoping I could ask the instructors/tech divers in this group about something,
Im doing a project and my topic asks, is scuba diving at 100 feet any more dangerous/risky than diving at 60 feet? (OW max depth and AOW max depth)
I would love if you are an instructor or tech dive(or whatever) and could chime in with what your stance on this is, and part take in my project. Please leave your cert and your cert number. I dont have to quote you if like, or I can, whatever you prefer. I would just like to hear what your stance on this.
Thanks for taking part!

Since you asked for qualifications, here are mine: I am a PADI MSDT with about 10 years of experience training divers and about 30 years experience diving. I am also an active technical diver, meaning I make at least one "technical" dive per week on average with qualifications from IANTD and TDI. I have been doing this since 2002. There is a lot I haven't done but I think I've done enough to justify giving you an opinion.

The question is if it is any more dangerous or risky at 100ft versus 60ft.

My short answer would be "yes" but I need to qualify that.

I'm assuming we're talking about making those kinds of dives with a normal diving configuration with a single AL-80 tank. (normal recreational gear).

Secondly, I'm going to define "total risk" to mean "chance" multiplied by "effect". In other words, if the chance that something happens is large but the problem it causes is small it will be a different risk profile than when the chance is small but the effect is enormous. In other words, risk contains within it the factors CHANCE and EFFECT.

First of all, what controls the dive? (chance)

Using normal recreational gear at 60ft *usually* (but not always) means that the amount of air you have in your tank is the controlling factor for your maximum bottom time. In other words, you will *probably* run low on air and need to ascend before you go over your NDL.

What changes at 100ft is that you normally *will* reach your NDL before your air supply is low enough that you need to ascend. That means that the controlling factor in the dive is the no-decompression limit.

Naturally we are taught to pay attention to both of these things but the diver needs to understand that the deeper they go the more important the NDL becomes. In a perfect world one would not go over the NDL but the CHANCE of doing so increases as you go deeper and therefore the risk profile (as defined above) changes.

How much time do we have to solve problems (effect)

To illustrate this, I'll talk about the amount of time we have to solve a problem. There can be issues when you go deeper with concentration and reaction times because of narcosis etc. but what it all boils down to in the end is the amount of available time you have to respond to a problem.

Simply put, the deeper you go (on air) the longer it normally takes to solve problems (there are exceptions) and the less time time you have to solve problems due to NDL and air supply restrictions. For example, if you are in 40ft of water and you get hung up on something, say a net, then you have effectively more time to deal with the problem AND you can respond with a clearer mind. If exactly the same thing happened at 100ft, you have a different risk profile. The CHANCE of getting stuck in a net at 100ft is no higher than it is at 40ft but the EFFECT (referring to total risk) could be many times more severe due to time restrictions on NDL and AIR.

When people talk about deep diving being "risky", this is what they mean most of the time. The deeper you are, the less available time you have to deal with excrement impacting the rotating blades.

Conclusion

Just looking at those two examples it's clear that you can think of ways that either the CHANCE of something untoward happening or the EFFECT of it happening at a deeper depth is increased at 100ft as opposed to 60ft. I've given you one example of each but I'm sure you can think of more for your assignment. My objective here is to give you a framework to analyse it, not an exhaustive list of everything I can think of.

Does that help you?

R..

 

[kensuf]

Hello! Im hoping I could ask the instructors/tech divers in this group about something,
Im doing a project and my topic asks, is scuba diving at 100 feet any more dangerous/risky than diving at 60 feet? (OW max depth and AOW max depth)
I would love if you are an instructor or tech dive(or whatever) and could chime in with what your stance on this is, and part take in my project. Please leave your cert and your cert number. I dont have to quote you if like, or I can, whatever you prefer. I would just like to hear what your stance on this.
Thanks for taking part!

Yes it's more risky. Here's why: you will go through the available gas quicker, which means you have less time to solve problems, and your inert gas loading will be higher, which means you will have either a reduced no-decompression-limit or a higher risk of decompression illness. Additionally, most people will be unable to perform a CESA below 60', which means they lose an emergency option (even though it's a bad option).

A very simple analogy: riding a motorcycle at 50mph has a certain level of risk. Riding a motorcycle at 70mph has a higher level of risk.

Stuff you asked about knowing is in my signature.

 

[2airishuman]

The meaning of the "depth limits" of OW/AOW are a subject of considerable discussion, which you can find by looking around; tl;dr version is that they are widely seen as guidelines for newly certified divers that do not necessarily apply to divers who have experience with progressively deeper dives after certification. The 130' limit for recreational diving is more widely respected, at least in the U.S., and relatively few divers exceed it without first obtaining technical training.

Deeper dives pose additional risks and this is covered during the AOW training. They can, to some extent, be mitigated by proper equipment and procedures. Statistical data appears to support this in the real world. The risks boil down to three areas: 1) the effects of pressure, which cause increased gas consumption and shorten the NDLs, and may lead to narcosis even at only 100'; 2) the greater distance to the surface making an emergency ascent more complicated; 3) ancillary factors; deep dives often equate to cold, dark dives.

Please leave your cert and your cert number.

Don't be ridiculous, this is the internet and you're not paying us.

 

[nadwidny]

Hello! Im hoping I could ask the instructors/tech divers in this group about something,
Im doing a project and my topic asks, is scuba diving at 100 feet any more dangerous/risky than diving at 60 feet? (OW max depth and AOW max depth)

Was an instructor for a couple of agencies. Not anymore. Still a tech diver I suppose. My answer is...a bit more but not really.

I would love if you are an instructor or tech dive(or whatever) and could chime in with what your stance on this is, and part take in my project. Please leave your cert and your cert number.

No.

 

[northernone]

Yes, all other factors remaining the same, deeper is more dangerous. As well presented by the generous professionals increased air consumption leaves less time for problem solving and secondly you are 30 feet further away from atmospheric air if it is needed as an alternative air source.

My instructor number isn't your concern.

Good luck with your project. I hope it helps support the public image of diving well. Keep us updated as we are now part of your project.


Regards
Cameron

 

[Doppler]

if it's too deep to stand up and take a breath of fresh air, it's dangerous... greater depth simply adds more complication to the equation.

 

[mmimadi]

Thank you for all your replies! As for me asking for your cert, I just wanted to make sure you were legit and it seams you guys are. Sorry, didn't mean to be rude by asking, I just had a lot of "noobs" try to answer.