Question about deco stops when diving with air.

[TSandM]

You don't need an extra tank, and you don't need a deco mix. What you need is an understanding of gas reserves (see THIS article by NW Grateful Diver). And you need to build a systematic scan of your environment into your diving procedure -- check depth and time, check buddy, look at the fish; check depth and time, check buddy, look at the fish, and every five minutes, add check gas to the list. This feels very artificial at first, and you'll feel as though it's taking away from the dive, but with practice, it becomes quite natural, and prevents many problems.

 

[ucfdiver]

Am I the only one that thinks this thread is getting dangerously close to teaching someone how to do things:
1- They're not ready for?
2- That they don't have the mentors to help them implement?

 

[AndyNZ]

Maybe carrying a small deco gas tank like nitrox must be obligatory for every diver.

In my experience, one of two things happen when people start doing this without really understanding the underlying issues.

1. They buy a small tank as "an emergency reserve", but that then gives them false confidence and end up doing more aggressive diving than the reserve can cope with. Quite often, it's just one person in a buddy pair with such a tank - and their false confidence pushes their buddy well beyond what is safe because "we have the pony".

2. People start pushing their dives to the point where they start taking a few sneaky minutes of gas from the tank to extend their dive, which then eats in to it's usefulness as an emergency reserve.


The bottom line here is that you need to learn to walk before you learn to run.


Maybe a good starting point would be an AOW course? That, at least, will give you some supervised experience at depth and a number of dives to improve your basic skills and knowledge. You don't really want a "off the shelf, one size fits all" course. So garner some advice from people here on SB on good instructors in your area.

No matter how much you read on the internet, or what other information sources you use - a PADI OW course does not provide you with a solid base of skills to be thinking about managing deco. Almost every "but I could do this..." you come up with will have flaws, and nothing beats some proper training to learn more about what you are getting yourself in to.

 

[impulse]

In my experience, one of two things happen when people start doing this without really understanding the underlying issues.

1. They buy a small tank as "an emergency reserve", but that then gives them false confidence and end up doing more aggressive diving than the reserve can cope with. Quite often, it's just one person in a buddy pair with such a tank - and their false confidence pushes their buddy well beyond what is safe because "we have the pony".

2. People start pushing their dives to the point where they start taking a few sneaky minutes of gas from the tank to extend their dive, which then eats in to it's usefulness as an emergency reserve.


The bottom line here is that you need to learn to walk before you learn to run.


Maybe a good starting point would be an AOW course? That, at least, will give you some supervised experience at depth and a number of dives to improve your basic skills and knowledge. You don't really want a "off the shelf, one size fits all" course. So garner some advice from people here on SB on good instructors in your area.

No matter how much you read on the internet, or what other information sources you use - a PADI OW course does not provide you with a solid base of skills to be thinking about managing deco. Almost every "but I could do this..." you come up with will have flaws, and nothing beats some proper training to learn more about what you are getting yourself in to.

Thanks for the great advice. I already took the AOW course. But did not go diving yet for improving my underwater diving skills. So I am an half AOW diver . I will go for diving next week. But what I think is that, PADI is just about money, you can become an OW diver, have 4 dives than get an AOW class and become an AOW diver next week after 4 more dives. Is this logical?

 

[Bubbletrubble]

I already took the AOW course. But did not go diving yet for improving my underwater diving skills. So I am an half AOW diver . I will go for diving next week. But what I think is that, PADI is just about money, you can become an OW diver, have 4 dives than get an AOW class and become an AOW diver next week after 4 more dives. Is this logical?

I can see why you might have that impression about PADI.
I think "logic" has very little to do with the training progression that you describe. Essentially, there's nothing wrong with having an OW student go directly into an AOW class to gain more supervised training in the sport.

We can argue all day about the semantics of the "advanced" designation. If you think that the AOW class makes one an "advanced" or experienced diver, then you are sorely mistaken.

Something is wrong when a basic OW diver does a dive beyond his training and experience. Either the instruction was inadequate or the diver was careless/exercising poor judgment.

 

[impulse]

We can argue all day about the semantics of the "advanced" designation. If you think that the AOW class makes one an "advanced" or experienced diver, then you are sorely mistaken.

Something is wrong when a basic OW diver does a dive beyond his training and experience. Either the instruction was inadequate or the diver was careless/exercising poor judgment.

I do ofcourse not think that the AOW class makes one an advanced or experienced diver. But an OW diver can dive 18m where an AOW diver can dive to 40meters. So I think PADI considers the certificate makes a diver more experienced, not me. When you become a one star CMAS diver, if I do not remember wrong, to take the next class you must have 20 logged dives. Which one is more safe? And I still think that logic plays a role about that, but ofcourse money plays a more important role.

You are right about your comment diving beyond the limits. But during that dive I was the only one who has OW certificate. So the instructer decided to exceed the limits. That's it. My instructer is a tech diver and he is exteremely experienced. He has over 10.000 dives. So he knows what he does.

 

[Matt S.]

Am I the only one that thinks this thread is getting dangerously close to teaching someone how to do things:
1- They're not ready for?
2- That they don't have the mentors to help them implement?

I don't see it that way at all. Everyone is saying, "do your best to never get into that situation, but if it happens, here is what to expect. But don't get into that situation. Really. Don't do it."

Knowing how a deco obligation works, and understanding what your dive computer tells you should you exceed NDL is quite prudent, IMHO. It's no substitute for a class, but I believe it is superior to willful ignorance of the topic so long as the diver is wise enough to know how much they still don't know.

I haven't gone back to re-read the entire thread but I can't remember any dangerous advice being given here. Instead I see some good mentoring, like TSandM's last post.

 

[Trace Malinowski]

Hello,

I am a PADI OW diver. And as you all know PADI OW divers do no deco dives. I have 55 logged dives.

During my last dive 5 days ago, I was watching my buddy taking photos at around 125 fsw. He was really bussy with taking photos. With the passion of taking photos, he, who has 25 logged dives, went deeper chasing a damn fish and I descended togather with him because he does not own a dive computer and was really careless about deco limits, we stopped at around 125 fsw, all the people in our group were at least around 16 fsw shallower, and they were watching a damn baracuda shoal. I forgot to check my dive computer for a while and was watching my buddy. The leader was watching us. Some time later I checked my computer and my eyes wide oppened becasue we had 1 more minute to enter deco. I really frightened and immediately warned my buddy and we started to ascend and the no deco time started to increase so we escaped from entering into deco. Maybe I prevented something bad? I do not know because I am not taught about how the decompression stops must done.

I do not know what to do If we entered into deco? Where to stop? Are the rgbm algorithm computers reliable about calculating deco stops?

From now on, I want to learn how to calculate deco stops when diving with air on my own. How can I learn that? Do you know a site or book teaching about that? I want to know about that.

I thought that you tech guys can help me out about planing the decompression stops when diving with air. I want to be extra safe in case of a compulsory deco stop. I like diving but do not want to die or become paralysed because of the decompression sickness. I want to know the rules firmly about the deco stops.

Thank you.

No, Impulse. THANK YOU. This is exactly why agencies used to teach (and some still do) decompression diving theory, procedures and tables in OW courses. You made an honest mistake. The only difference between what you did and what I've witnessed and have been part of as a trained decompression diver is that I know what to do when we've exceeded the planned bottom time or depth. You've illustrated why training agencies should never have removed more complete training for OW divers. Some basic deco diving understanding and some rescue training goes a long way.

Through your mistake, you had an experience and learned a valuable lesson. Until you get more training, just be more careful in the future. AOW would be your next step in the traditional process and some agencies teach deco diving in AOW. Or, you can move into DIR training with GUE, UTD or ISE. After AOW you can do advanced nitrox/deco procedures or triox training.

When diving air, most computers or tables will have you stop at 10 feet then 20 feet. Some will give you a deep stop at about 50% of your max depth. It's important to know that your ascent rate is part of your deco on any dive. Don't rush it. Ascend at 30 feet per minute or whatever rate your computer gives you. You'll begin to off gas at about 80% of ATA or 75% of depth on deeper dives and at about 50% of depth on recreational dives. There is no reason to panic if you find yourself in the same situation again. Just relax and ascend slowly. Make all the stops that your computer tells you to make. Stay at that depth until you are cleared to move up the water column. While that sounds easy and you might be tempted to start doing deco dives, there is a lot more to it than that. Be trained. In technical diving untrained divers are one of the biggest fatality statistics.

Another issue of concern issue will be gas management not just nitrogen in your tissues. Unplanned deco for recreational divers without skill and training can end up moving into an out of air situation and double the trouble.

I'm sorry that your training did not include what to do in the event of an accidental deco obligation. I get angry when I read stories like yours and such instances are precisely why OW training needs to go back to a complete course concept.

 

[Bubbletrubble]

I do ofcourse not think that the AOW class makes one an advanced or experienced diver. But an OW diver can dive 18m where an AOW diver can dive to 40meters. So I think PADI considers the certificate makes a diver more experienced, not me. When you become a one star CMAS diver, if I do not remember wrong, to take the next class you must have 20 logged dives. Which one is more safe? And I still think that logic plays a role about that, but ofcourse money plays a more important role.

I have had all of my formal dive training through PADI, and I would say that the quality of the instruction and the disposition of the student/diver are far more important than the agency's prescribed training progression....in terms of safety for recreational diving. That being said, it certainly would be preferable to have the "complete course concept" that TraceMalin describes above.

You are right about your comment diving beyond the limits. But during that dive I was the only one who has OW certificate. So the instructer decided to exceed the limits. That's it. My instructer is a tech diver and he is exteremely experienced. He has over 10.000 dives. So he knows what he does.

Just because your instructor was a highly experienced tech diver/instructor does not mean that he exercised good judgment in the given scenario. If something doesn't seem right/safe given your current level of training and experience, don't do it. Period.

 

[boulderjohn]

I'm sorry that your training did not include what to do in the event of an accidental deco obligation. I get angry when I read stories like yours and such instances are precisely why OW training needs to go back to a complete course concept.

That information was covered on question #2 of Knowledge Review #5 in his academic course work.

It is written on the back of the Recreation Dive Planner that he was issued.

It was a question on the final exam.