Mass confusion about computers????

[KenGordon]

You are missing a MAJOR point: which computer you use is not nearly so important in risk mitigation as staying within the NDL, ascending slowly, doing a safety stop, staying hydrated and warm, etc., all the things that much more contributory to DCS. Your argument is analogous to saying that if I'm going 100 mph down the highway while drinking a cup of coffee and reading text messages on my phone, that my risk is higher if my car seat is poorly adjusted. It may be marginally true, but it is really not the risky thing to pay attention to.

Since the NDL depends on the computer, what staying within the NDL means depends on the computer. Staying longer increases risk, so diving a longer NDL increases risk.

In your analogy i’d be drinking coffee at 70 while you’d be doing 80.

 

[KenGordon]

Alert Diver | The Many Factors in Decompression Stress
View attachment 446896

The computer, and immediate diver choices, influence the top left portion leading to the profile. The rest matter but are not part of the confusion about computers.

So, I give in. I will buy a DSAT computer and try it out. Is a Veo 3 a reasonable example or will you all come back later nd say it is a special case and not representative?

 

[dmaziuk]

This is really the point, isn't it? If one is doing NDL diving, then some of the nuances relative to deco diving are irrelevant.

Sorry, you can't have it both ways: either staying down longer and run more "liberal" profiles increases your risk of DCS or it does not.

 

[tursiops]

Sorry, you can't have it both ways: either staying down longer and run more "liberal" profiles increases your risk of DCS or it does not.

Not gonna play.

 

[scubadada]

The computer, and immediate diver choices, influence the top left portion leading to the profile. The rest matter but are not part of the confusion about computers.

So, I give in. I will buy a DSAT computer and try it out. Is a Veo 3 a reasonable example or will you all come back later nd say it is a special case and not representative?

Time at depth is the major risk factor for DCS. The question is, do any of the availabe deco algorithms have a significantly higher risk than others? I thought DAN Project Dive Exploration might have a chance to shed some light on this question, but, have largely given up on this possibility.

The Veo 3 is fine, DSAT is DSAT, other than the conservative factor. Look forward to hearing about your experience.

 

[tursiops]

Since the NDL depends on the computer, what staying within the NDL means depends on the computer. Staying longer increases risk, so diving a longer NDL increases risk.

Yes, if you re working near the edge. The computers we are talking about are so far from the edge that it is hard to see the edge while using them. That is, diving them to NDL is still a long way from the edge, so how does it matter how far from the edge I am? You are being theoretical; I am being practical.

By the way, diving ANY computer near its NDL is a bad idea, as you know, but some reading this may not. It it trips over into deco, then all bets are off on risk mitigation. Get up to 10 ft, or whatever the computers shows, at 30 ft/min, and hang there for a good while. Yes, you've only exceeded NDL a tiny bit, but the problem is now gas management more than DCS. You know this, of course, but anyone unsure how their computer works probably doesn't.

 

[KenGordon]

Yes, if you re working near the edge. The computers we are talking about are so far from the edge that it is hard to see the edge while using them. That is, diving them to NDL is still a long way from the edge, so how does it matter how far from the edge I am? You are being theoretical; I am being practical.

By the way, diving ANY computer near its NDL is a bad idea, as you know, but some reading this may not. It it trips over into deco, then all bets are off on risk mitigation. Get up to 10 ft, or whatever the computers shows, at 30 ft/min, and hang there for a good while. Yes, you've only exceeded NDL a tiny bit, but the problem is now gas management more than DCS. You know this, of course, but anyone unsure how their computer works probably doesn't.

If nobody ever got bent then you might claim the NDLs are so far from the edge it doesn’t matter, but people do get bent and many are within the tables/computers.

The people criticising the ‘conservative’ computers and trumpeting the likes of DSAT or a x/95 GF are looking to use the gap between the NDL of one and the NDL of another, otherwise they would not care about the difference.

If crossing into deco is the only failure, and they notice within a reasonable time, then they gas plan ought to be adequate. The initial mandatory stop would be less than the safety stop. Of course if the first failure is not having a gas plan then they might be having less fun, or if they spend ten minutes wondering why their NDL is going up having been to zero they will be in for a nail biting time. But these are mostly human errors rather than computer issues (although whoever thought that replacing a count down of ‘good’ with a count up of ‘bad’ , in the same field, with only a little icon to tell which is which clearly needs some UX help).

By the way, learning about working dive computers on the internet is a bad idea, if anyone reading that hasn’t worked that out they ought to seek help from a physical person, paid money (or in a club) and with a duty of care. Reading the manual might help too.

 

[tursiops]

If nobody ever got bent then you might claim the NDLs are so far from the edge it doesn’t matter, but people do get bent and many are within the tables/computers.

Those that get bent within their NDLs: what tables/computers are they using?

 

[stuartv]

By the way, learning about working dive computers on the internet is a bad idea, if anyone reading that hasn’t worked that out they ought to seek help from a physical person, paid money (or in a club) and with a duty of care. Reading the manual might help too.

I agree with what has already been alluded to. I think ScubaBoard is a great place to get information about every aspect of diving that I can think of. There is a helluva lot more peer review that goes on here than if I go to any local dive shop and ask whoever I find working there a question.

Information from someone with a duty of care should be recognized to be coming from a biased source. They are inherently biased to give you information that does not expose them to risk. E.g. an engaged dive professional is very unlikely to tell a recreational diver anything other than "if your SPG fails, end the dive immediately." An experienced diver who has no duty of care might tell the same recreational diver, "learn your SAC. Know your SAC. Monitor your tank pressure closely. If your SPG fails, use your knowledge and judgment to decide when to end the dive."

A pro whose ass is on the line if you get hurt may be the best source of info - because they have a vested interest in your health and safety. Or, a person who has nothing to gain OR lose from your health and safety may be the best source of info. Every diver needs to take responsibility for themselves, including making their own decisions on what information to accept, question, or reject.

 

[scubadada]

Those that get bent within their NDLs: what tables/computers are they using?

I would imagine that divers suffer DCS using all computers and all algorthms within NDL. I would wager some of those episodes are due to other diver errors and some are unexplained and demonstrate the bell-shaped curve of human response.