Why the dislike of air integrated computers?

[AfterDark]

Huh? Does your dive computer check your c-card?

No but the op does. If I stay down longer than the NDL I deco, by the time what I'm doing would be discovered it's too late, it's done. The USN air tables provides me with guidelines for deco times and stops using air only. Of course that's the ops that don't check PDCs. Some are really great, they pretty much let me do what I want to do once they get know me. Others, well I'll just ask forgiveness if I ever get caught. Getting off topic with this aren't we? Don't make me report you

 

[doctormike]

Getting off topic with this aren't we? Don't make me report you

Are you kidding? I may be just a medical mod, but even I know that it's a TOS violation to go more than four posts without switching topics...

 

[dmaziuk]

I'm sorry, but this sentence makes no sense at all. I've never heard air consumption quantified as "a minute of air per second". Also, If you are down to less than five minutes of air, no analog or digital device will make up for your inattention.

If you are in this scenario, then instrumentation - analog or digital - is irrelevant. You are surfacing, getting some sort of redundant gas supply, or drowning.

Out Of Context Error: I was following up on Krakens "If you're diving that close to the edge, well . . . ." I.e. the circumstances in which you need a sub-second resolution on your air pressure gauge is as you both say: you shouldn't be there in the first place.

Converting <your favourite unit of volume> per second to minutes of breathing time: one would assume if you're down to your last minutes of ATR, you're on your way up. So your ATR increases with every foot traveled. At the same time it also decreases with every breath taken. Doesn't everyone do second derivatives for breakfast?

But put me down in the "had frequent AI link failures, especially with strobe photography, and gave it up" group.

The thing about these statistics is that no one has really global link failure statistics. So if you have a good WAI system and you do 100,000 dives, then you will conclude that the WAI failure rate is less than one in 100,000. On the other hand, if there are 10 divers and two of them have had issues with link failures, then that's very significant statistically.

So posting here that you have never had a link failure is interesting, but not very relevant statistically. If 95% of the posters here swore that they never had a link failure, and 5% had, that would be an unacceptable failure rate, despite that huge number of glowing reviews.

I'm not saying that those are real numbers, it's just that link failures are pretty common complaints, so I wouldn't dismiss them

I suppose flash discharge could generate enough EMP to interfere with the [very weak] NFC signal. My point was that if the link is re-established by the time you look at your wrist, who cares. Do you know the link is up while you're not looking?

Where I work people say "we reached one million data points, now we can finally run some meaningful statistics". And quietly laugh at medical studies that go "we had a sample of 20 patients and half were given placebo... and our statistically valid conclusions are". 95% of 10 divers is not statistics. 95% of 10,000 divers may be but then you might want to to bucket them into tec, rec, flash photographers, old vs new computers, etc. to make the statistics actually mean something.

 

[The Chairman]

Out Of Context Error: I was following up on Krakens "If you're diving that close to the edge, well . . . .".

Yeah, I read both of his comments, and it's still nonsensical. Again, 'a minute of air per second' is a flawed method of measurement.

 

[boulderjohn]

No but the op does. If I stay down longer than the NDL I deco, by the time what I'm doing would be discovered it's too late, it's done. The USN air tables provides me with guidelines for deco times and stops using air only. Of course that's the ops that don't check PDCs. Some are really great, they pretty much let me do what I want to do once they get know me. Others, well I'll just ask forgiveness if I ever get caught. Getting off topic with this aren't we? Don't make me report you

If I understand this correctly you are saying that by diving the USN tables with their schedule of air decompression, you are able to do reasonably short deco stops on a dive in which you are not supposed to go into decompression, because the operator will not know you are going into decompression.

Did you ever consider that if there were any multilevel aspect to your dive whatsoever, if you were using a computer instead of the USN tables, your computer would probably not be in deco for the dive? If you are generally coming up at about the same time as the other divers on a trip, it may well be that you are the only one trying to get away with going into deco. The rest probably have plenty of NDL time on their computers, even though they did the same kind of dive you did.

I have never had a dive operator check my computer at the end of the dive. I am presently using a Petrel, and I have it in tech mode even on recreational dives. It gives me a short NDL because it considers it a deco dive if I have to do even a one minute stop before ascent. Technically, I go into deco on nearly every recreational dive, but it is all clear by the time I have done a standard 3 minute stop. Nobody checks.

 

[doctormike]

Yeah, I read both of his comments, and it's still nonsensical. Again, 'a minute of air per second' is a flawed method of measurement.

Ask if he can make the Kessel run in 12 parsecs...

 

[dmaziuk]

Yeah, I read both of his comments, and it's still nonsensical. Again, 'a minute of air per second' is a flawed method of measurement.

Re-edited for your reading pleasure.

 

[doctormike]

I suppose flash discharge could generate enough EMP to interfere with the [very weak] NFC signal. My point was that if the link is re-established by the time you look at your wrist, who cares.

It didn't. One of the reasons I got rid of it.

Where I work people say "we reached one million data points, now we can finally run some meaningful statistics". And quietly laugh at medical studies that go "we had a sample of 20 patients and half were given placebo... and our statistically valid conclusions are". 95% of 10 divers is not statistics. 95% of 10,000 divers may be but then you might wanto to bucket them into tec, rec, flash photographers, etc. to make the statistics mean something.

I guess, but if the best that you can say about WAI is that further research may show which subset of divers have acceptable failure rates, that's not saying much.

My point is that there are a LOT of people on this board who have ditched WAI because of sync/reliability problems - this isn't the first thread on the issue, and I have read a lot of them. It is impossible to draw meaningful statistics out of these posts because of the reporting issue that was mentioned above. People with faulty systems are going to be more likely to post.

But it IS reasonable to assume that this is not an isolated problem. And it IS reasonable to conclude that if you have a working WAI computer, it possibly will always work, and no matter how many successful dives you do with it, that doesn't change the overall failure rate for everybody else. If you have two divers with two WAI computers, and one does 10 dives and it never works, and the other does 10,000 dives and it always works, the failure rate per unit is 50%, not 0.1%.

My other point was that even with an abysmal failure rate for any product of, say, 20% will still result in the vast majority of users being very happy with the system, and possibly writing glowing reviews if asked.

Finally, 95% of 10 divers makes me wonder about a serious shark attack somewhere along the way..

 

[dmaziuk]

Ask if he can make the Kessel run in 12 parsecs...

It so happens I just had a conversation with someone along these same lines: she was re-reading some old Azimov story and in the translation she had the spaceship "flew west".

---------- Post added July 9th, 2015 at 03:33 PM ----------

Finally, 95% of 10 divers makes me wonder about a serious shark attack somewhere along the way..

Oh good, we'll have you do double-integrals next.

I do know a little about the hardware and software involved and sometimes I think it's a good thing they cost too much for the convenience they offer: otherwise I'd think of actually buying one and be very very scared about those things... But they do get better with every next generation.

 

[Got2Go]

Haters gonna hate...

I like my wireless air integration, AND my analog/backup spg.