"Riding your Computer Up" vs. "Lite Deco"

[boulderjohn]

If you are PADI-trained, then you should be using PADI tables and any given NDL is clear and well-defined. But, if you are PADI-trained (only) and decide to use NOAA or SDI or whatever tables, then you are violating your training.

No, you are not "violating" your training. You are just using different equipment than what was used in your training. It would be similar to a person taking drivers education in a car with a stick shift and then driving in a car with an automatic transmission. It is just different--not a violation.

 

[scubadada]

Remember there is more to tables than NDLs. The PADI NDLs are shorter than the old Navy ones in large part because they wanted to shorten the surface intervals before subsequent dives.

They changed the controlling compartment from 120 minutes to 60 minutes, and even discussed using 40 minutes

 

[lowviz]

... I'll disengage for a while and leave the internet divers to astound themselves with their own brilliance and insight

No, no! Don't leave, you are loving this discussion too.

Let's call it a draw, I'll stop annoying the piss out of you if you stop calling me names.

... The point being, teaching core concepts of a dive computer algorithm is a nice idea but having an actual dive computer for that sounds like a complication that makes it, very relevantly, impractical.

You still don't get it. Nobody is teaching the algorithm, they are teaching how to dive a computer.

Nobody taught me the core concepts of tables, they taught me how to dive them. But the tables, by their very nature, are immutable and standardized.

Once again, from the top: The OW/AOW agencies get together and define a dive computer standard program. Lots of them out there in the public domain. Pick one, alter it. It could be as conservative or aggressive as they wish, I don't care in the least. Decide on how to handle ambient pressure, sampling rate for the depth measurement, and agree on what every DC manufacturer should offer as the two standard training options in their recreational DC. The third option is whatever the hell the manufacturer wants to try to sell as their implementation to whatever.

Now, OW class begins with: "OK, show me that you all have your DC's in OW Standard."

Read this Development of Iso-DCS Risk Air and Nitrox Decompression Tables Using Statistical Bubble Dynamics Models. ...//...

Wow, what a read!

A-2, the abstract, is worth reading. But they are using 3 parallel compartments. I believe that OW/AOW could be done with a program that is limited to only the fastest tissue group. No need to teach that, but now they have a defensible standard that allows for subsequent dives.

 

[redacted]

Lets ask the experts!

Common sense dictates that the closer you are to the cliff your chances of falling over it increase.

I agree if you are close to the cliff. But when you are a mile from the cliff, backing off another mile has no effect on your probability of falling off. Think of it as a step function: one more step and you are gone.

Much like the water and electrolites, N2 does not cause DCS until it comes out of solution and forms gas bubbles. As long as disolved N2 levels are not too high, off-gassing is acomplished by N2 moving from various tissues into the circulatory system in its disolved state until it is expelled in the lungs.

Perhaps it is just easier to teach that if you go under water, you risk DCS. Or do you really believe that is the case?

 

[Scuba J7]

That would be similar to someone in the 1950s wanting to require all doctors treating polio victims to use the same iron lung protocol and requiring all iron lung manufacturers to use the same methodologies for manufacturing iron lungs. If we did that then, we would still be using iron lungs today. If you are going to stifle research and innovation, you should have a pretty darn good reason. I have for the life of me not seen any reason for doing this, let alone a good one. Yes, different algorithms produce somewhat different results. So what? Can anyone identify a problem that has resulted from this that requires such a drastic solution?

I totally agree, was being sarcastic in that post. I'm still trying to figure out what this thread has turned into and what the issue is with manufacturers using different algorithms, especially since DSAT is considered the most liberal but still safe. I teach tables and offer to help my students with whatever computer they wish to use if they choose to. I'll explain differing algorithms as best I can, but being PADI trained I know more about DSAT...right now anyway.

 

[boulderjohn]

They changed the controlling compartment from 120 minutes to 60 minutes, and even discussed using 40 minutes

I think I have written the full story of the development of the PADI tables 3 times in this thread alone in order to try to control at least some aspects of the flood of misinformation being spewed out in this thread. (BTW, you did not mention that they considered using the 40 minute compartment because that was what their research indicated made sense, but they decided to use the 60 minute compartment to be more conservative. They also put in more pressure groups to decrease rounding. There. Is that the 3rd or 4th time I've explained it. I've lost count.)

 

[KenGordon]

No, it would not.

For most recreational divers, the risk of DCS when they stay within their NDL and ascent rate limits is NEGLIGIBLE. When they exceed those limits, the risk of DCS are INCREASED.

Why do you think this?

I have met several divers who were bent on no stop dives. One turned out to have a PFO, but had been diving, including substantial deco dives, for many years. One had got bent on a OW course in Egypt and another on a 15m dive.

If you read the BSAC incident reports you will find about 70 or 80 DCI incidents each year. Obviously some of those will involve proper deco dives, bad ascents or some obvious reason, but there are some which happen on simple NDL dives.

 

[scubadada]

I think I have written the full story of the development of the PADI tables 3 times in this thread alone...

As have I, looks like many were not paying much attention to some of the more factual posts. At least you and I are on the the same page

 

[Scuba J7]

I agree if you are close to the cliff. But when you are a mile from the cliff, backing off another mile has no effect on your probability of falling off. Think of it as a step function: one more step and you are gone.

Much like the water and electrolites, N2 does not cause DCS until it comes out of solution and forms gas bubbles. As long as disolved N2 levels are not too high, off-gassing is acomplished by N2 moving from various tissues into the circulatory system in its disolved state until it is expelled in the lungs.

Perhaps it is just easier to teach that if you go under water, you risk DCS. Or do you really believe that is the case?

If your breathing compressed gas while underwater. Do you really believe you only risk DCS when close to an NDL?

 

[lowviz]

I think I have written the full story of the development of the PADI tables 3 times in this thread alone in order to try to control at least some aspects of the flood of misinformation being spewed out in this thread. ...//...

This thread has nothing to do with the development of the tables.

They exist, they are standardized, and they resist fudging. Much to be said for that.

DC's: personal preference...