When is it okay to exceeding training limits?

[boulderjohn]

I don't know how often this needs to be said before people begin to get a grasp of it. Neither PADI not any other agency is a legislative body. It does not make laws. It can and does tell its instructors what the limits are for training dives, but it has no authority to tell you what to do on your personal dives. It can only recommend.

Now, a dive operation is a different matter. Many dive operations will set their own rules. They can say that if you are going to dive with them, you have to follow certain guidelines. If you don't like those guidelines, you will need to dive with someone else.

Legislative bodies can also set certain rules, and in some localities there are legal limits to diving not found in other places. For example, int he Cozumel marine park, you must dive under the supervision of a divemaster.

 

[Basking Ridge Diver]

There is a thread about the relation of breathing rate to on-gassing and off-gassing roughly once a year. I started one about 9-10 years ago myself. Check the Ask Dr. Decompression forum especially. Here is the quick summary to save you time: contrary to what might seem to be common sense, the rate at which you breathe has no effect whatsoever on your on-gassing and off-gassing. If you understand diffusion--the process by which gases enter and leave our bodies--you will see why.

Thanks Dr Deco,
I think I understood that.

DCS is not a problem of getting the nitrogen out of the blood through the lungs per se, but is getting the nitrogen out of the tissue into the blood. Now that I think about it, that seems obvious and my question silly!
So that must be the reason why decompression profiles are calculated using different tissue compartments, because different tissues give up the nitrogen at different rates/pressures?? Am I kind of in the ballpark??
I think I have some reading to do!!

Thank you - doing a search on Diffusion helped - lots of threads - lots of information. But my search just needed your prodding with the key word... I will try other searches but this helped me.

 

[Bob DBF]

KWS: the PADI Open Water final exam has a question about recommended versus maximum depth; I'm not qoing to quote it because it is a final-exam question! But the official answer is 60 ft is recommended for OW-level divers, 130 feet is maximum for all recreational divers. The word "limit" is not used, so you really ought to get over it. Please remember that "certification" is a statement of having been trained, not a permit or a license to go do something.

The reason for vagueness is that you are taught to dive within no decompression limits, not to any specific depth. That was why the cutoff when I was initially trained was 190, because you could do a no decompression dive to that depth, 200' would give you a minimum 1min deco @10'.

130' is not the limit for recreational divers, as "tech" divers are also recreational divers. The difference is that tech divers are trained for decompression diving, which no longer limits them to NDL diving. At one time in the not so distant past, the training for deco diving was done without formal certification.



Bob

 

[KenGordon]

This thread seems to be more about the wording of PADI documents than diving. Let's consider what diving beyond the training depths means. It will mean increased gas consumption, increased decompression obligations and increased likelihood of narcosis. Will you be able to cope? Have you been taught how to calculate how much gas a dive requires? Do you know your SAC? Have you experienced any stress underwater and seen the difference?

During instruction and the detested 'trust me' dives someone else will be considering these points. You may be able to pick them up from other divers, books, forums, etc. diving isn't all that complicated after all. On the other hand how can you decide whether 75ft, 85ft or 185ft is ok? How can you know what subtle thing you don't know needs consideration?

If you follow a training program it will have been designed to introduce required knowledge before it is needed. Much less stressful than the other way round.

Diving with a bunch of knowledgable people is also good. Not all instruction has to be formal. Do make it a bunch though, not just one.

Ken

 

[Dr. Lecter]

You may be able to pick them up from other divers, books, forums, etc. diving isn't all that complicated after all. On the other hand how can you decide whether 75ft, 85ft or 185ft is ok?

I dunno, basic math and even a DSD student's understanding of diving physics/physiology?

 

[Doomnova]

I dunno, basic math and even a DSD student's understanding of diving physics/physiology?

Your also forgetting a pinch or two of logic and common sense(some would argue they are one in the same).

 

[dberry]

As an older guy who is new to both diving and reading these boards, I just want to thank you all for this thread. It's been a fun and enlightening read, and good to see the wide variety of opinions, advice, and (largely) good-natured disagreements. As a newbie diver, even *I* don't care about *my* opinions on the technical stuff, but I can offer a few thought from a guy who has survived some other activities like rock climbing, winter camping at altitude, and even working with nasty chemicals and explosives upon occasion. (Still have all my fingers, but my hearing ain't what it used to be.)

(1) It's impossible to increase your experience level without taking some risks. You can't find your limits without testing them a bit.

(2) The longer I live, the more guys (and gals) I've seen get hurt or worse despite their extensive experience; bad stuff can (will) happen. But, push the limits hard enough, often enough, and the bad stuff happens more often. (I'm talking non-SCUBA, but I imagine it's true under the water, too.)

(3) It's an old cliche', but the main thing I've learned with time is how much I don't know. And that as soon as something seems idiot-proof, God creates a better idiot. I just don't want that idiot to be me.

(4) I've also figured out that I make mistakes sometimes (shhh, don't tell the wife.) Over the years, I've had more than a few snafus that, after the adrenaline has worn off, have left me in a cold-sweat thinking about what might have happened. Those used to be funny stories to share over a beer, but less so as I see more Bad Stuff happen to others. So, as I start to accumulate diving experience, I intend to assess my own limits pretty conservatively. I guess I've figured out that I'm not infallible, or immortal. You can call me a "wuss", but I think of it as "life experience" <shrug>.

(5) questions about insurance and whether ignoring PADI "guidelines" increase liability only matter to the professionals among you; I mainly care about making it back to the surface alive and without major injury.

At the start, a newbie doesn't know enough to know where to set limits. IMO, THAT'S what the PADI guidelines are about - rough limits as a starting point for the ignorant newb. There are plenty of ways to get into trouble in 0 - 60' of water as a start. If you're going to go deeper, maybe it should be with someone who knows a LOT more than you do. And is willing to watch your back, not an insta-buddy.

Thanks again for the thoughtful thread on limits.

Now I'm off to ask some dumb questions in other threads... gotta work on my idiot-proofing.
TTFN,
Don

 

[kafkaland]

Out of curiosity: How many dive ops insist on a Deep specialty to dive the 100-130ft range? I have been on such dives a few times, but don't have the deep card. I know a thing or two about redundancy and dive planning from more experienced buddies, the Intro Cave course, etc., and generally felt quite comfortable in that depth range, but of course there is always something to learn. My LDS recommends that I take the Deep course rather sooner than later, but looking at the curriculum, I'm not sure that I'd get much out of it. Or would it be reasonable to get a few more 100ft+ dives in, with dive ops that let me, and then take Advanced Nitrox / Deco Procedures at some point, skipping the Deep course altogether?

 

[boulderjohn]

Out of curiosity: How many dive ops insist on a Deep specialty to dive the 100-130ft range? I have been on such dives a few times, but don't have the deep card. I know a thing or two about redundancy and dive planning from more experienced buddies, the Intro Cave course, etc., and generally felt quite comfortable in that depth range, but of course there is always something to learn. My LDS recommends that I take the Deep course rather sooner than later, but looking at the curriculum, I'm not sure that I'd get much out of it. Or would it be reasonable to get a few more 100ft+ dives in, with dive ops that let me, and then take Advanced Nitrox / Deco Procedures at some point, skipping the Deep course altogether?

I have never encountered an operator that required the deep dive specialty for any dives. The deep dive specialty can be very helpful, especially if the instructor chooses to go more deeply into gas management during that training. The deep dive course is not a requirement for AN/DP. That course combination is much more oriented toward diving skill than to being accustomed to depth.

 

[TSandM]

When we went to Indonesia, we started at Tasik Ria with Eco Divers. There, we were segregated into groups, and each group had a depth limit. I was in the 80 foot limit group, because I only had my AOW card with me, and not my Deep specialty card. Didn't matter to me; I didn't want to go any deeper than that, anyway.