Question about deco stops when diving with air.

[ucfdiver]

If you can't adhere to a NDL limit, you'll just end up breaking the deco plan once you get the training. Irresponsibility isn't fixed by training. I would just continue to dive unsafe at the OW level rather than blowing money on a deco course with your maturity level.

 

[AndyNZ]

If I did not look I would not see we were about to exceed the NDL. Why you always accuse me and not say that, yes decompression rules are important, every diver must learn about that.

Something that you may eventually learn is that ultimately, when it comes to decompression, there are no rules.

There are a collection of guidelines that are based on relatively little evidence. Those guidelines are such that most people, most of the time remain DCS symptom free.

 

[bleeb]

From the other side of the NDL line from decompression diving, something else worth thinking about:

In a lot of vacation spots, a lot of operations seem to favor 80 cu.ft. or 12 L tanks. Philosophically, one of the reasons sometimes given is that the supply of gas is deliberately limited to keep possibly unpracticed divers from getting too far into deco.

Applying a similar philosophy to your personal equipment, this might suggest carrying a pony bottle might not be as good a practice UNLESS you already had the knowledge, skill and discipline to not get yourself into a situation where you needed it without something somewhat unusual happening.

Any additional comments, particularly from those with deco training?

 

[ucfdiver]

From the other side of the NDL line from decompression diving, something else worth thinking about:

In a lot of vacation spots, a lot of operations seem to favor 80 cu.ft. or 12 L tanks. Philosophically, one of the reasons sometimes given is that the supply of gas is deliberately limited to keep possibly unpracticed divers from getting too far into deco.

Applying a similar philosophy to your personal equipment, this might suggest carrying a pony bottle might not be as good a practice UNLESS you already had the knowledge, skill and discipline to not get yourself into a situation where you needed it without something somewhat unusual happening.

Any additional comments, particularly from those with deco training?

I think it's another case of using gear to fix a skill problem. The OP is just too irresponsible to be diving, period. Gear isn't how you fix that.

 

[TSandM]

The OP is also a pretty new diver. He's got a lot of lessons yet to learn. He got one from the reported dive, but what worries me is that it was the wrong one. Instead of learning the lesson that he needs to monitor his status more diligently and do a bit more pre-thinking about his dive, he got the lesson that he needs to study decompression theory. Studying theory isn't a BAD thing (I wish more people would do it) but the real lesson is to be more careful. I hope he's heard that one from us.

 

[lamont]

Maybe carrying a small deco gas tank like nitrox must be obligatory for every diver. But I think this would change all the diving rules. Just a thought. May help to avoid health issues before they show up.

That is exactly the wrong instinct, and the wrong message to take away from what everyone has posted. Although it is a common response of newer divers to the problem of diving deeper/longer to go out and get more gas.

A pony bottle introduces another valve, another SPG, another tank neck o-ring to bubble and leak, another regulator to make sure is deployable and breathable underwater. And if any of those things go wrong, it is a worse than useless piece of gear because it just introduces complacency about your ability to dive deeper/longer.

What you need is skills:

- ability to hold buoyancy control and trim at your stop without a reference

- ability to donate gas safely and efficiently every time

- ability to manage your gas

- ability to plan and execute your dives

You should be able to check off all those skills before you start bumping up against the NDLs. Right now you should be leaving the bottom with a lot of NDL padding available to you so that you don't incur any real decompression.

Later, you will probably have a sufficiently low SAC rate due to comfort in the water that being aggressive on a dive by a few minutes and incurring a few minutes of mandatory decompression that you can do aggressive NDL dives without additional gas reserves.

So, you've got it completely backwards. Don't buy gear and also don't worry about learning about decompression. You need to go out and become a better diver through experience and more training. You need to focus on your fundamental skills, and not decompression -- GUE fundamentals, UTD essentials and NAUI intro to tech, would be courses that I'd encourage you to look into -- you don't need a deco procedures course right now.

 

[Mattleycrue76]

Impulse, let me ask you a question:

You seem very worried about suddenly and unpreparedly running out of "no deco time".

There is another limited recource in diving with a much harder and unforgiving limit - your gas supply.

If you don't have the awareness to complete a dive and respect/stay within your no decompression limits, what makes you think you can stay within the limits of your gas reserves?

After all both require esentially the same planning, execution, and awareness skills except that a couple of minutes of omitted deco will likely cause nothing but a good nap while running out of gas could kill you if your buddy is off photographing the pretty fish when it happens.

 

[AndyNZ]

Applying a similar philosophy to your personal equipment, this might suggest carrying a pony bottle might not be as good a practice UNLESS you already had the knowledge, skill and discipline to not get yourself into a situation where you needed it without something somewhat unusual happening.

Any additional comments, particularly from those with deco training?

You have to ask what the pony is for, though.

Is the pony being used to provide with redundancy in case of an equipment failure?

or

Is the pony being used to provide an additional gas supply because someone doesn't know how much gas they actually need to do a given dive.


IMHO, the latter is completely the wrong reason to carry a pony. With the former, you need to think about worst case - an equipment failure occurs in the last minute of your planned bottom time and you have to do your entire ascent including deco stops using the pony (ignoring presence of buddies).

Most pony bottles are too small to enable you to do this - so you have created another problem by carrying, over-confidence to allow you to push your dives times without actually having the skills, knowledge or equipment to do so.

I believe that pony bottles have their place as "emergency ascent bottles" for dives within recreational limits - even then, anything smaller than 30 cu ft is really pushing it. For dives involving decompression, twin tanks are a much better option.

The two problems with twin tanks, though, are:

1. An increased level of complexity and new set of skills required to use safely
2. You are no carrying enough gas to seriously hurt yourself unless you dive a plan and stick to it....


Whilst it may sound harsh, I think the OP is the kind of diver who would end up doing just that.... hurt themselves badly by not being able to stick to a dive plan.

 

[impulse]

Whew!


OK, thanks for the response. You have told me all I need to know about you and your attitudes and beliefs toward diving. I won't bother you any more. Sorry I offended you earlier. Go on with our life plans.

What I told you is what I saw. I like diving alot and my beliefs toward diving is that, diving is a very exciting and important activitiy for me. I can spend all my life being a diver. And more over no post here offended me. I just try to understand something. You do not bother and I did not mean to be rude or disrespectful.

I know that I must not exceed NDL as being a rec diver. The reason why I oppened this thread is for gethering more information. But it is carried to another dimension.

 

[impulse]

I think it's another case of using gear to fix a skill problem. The OP is just too irresponsible to be diving, period. Gear isn't how you fix that.

I am just a new diver and I am seeking advice. If I was irresposible I would never think about what happened during my last dive and never ask it here. I am resposible and the orginal post itself proves that. At least I am trying to understand and seeking advice.

And I now am thinking that I am wrong about the whole decompression concept. You were right about it. I have very limited experience about scuba diving and have fallen into the trap thinking that there must be something missing that is not thought at the OW classes. But now I understnad I am wrong. Staying inside the NDL is the smartest decision at this level of my mine.

But I still will take the deco class.