tank pressure redundancy

[Soggy]

One useful bit of info my AI provides me with (that the spg+timer can not *directly* do) is show me the *time* I have left on my tank based on my current breathing rate + depth + psi.

How is this number useful? Does it allow you to configure your rock bottom psi number or is it like my old Aladdin Air computer that just arbitrarily used 800 psi as "time left." When you reached that number, it flashed "0" as your time left, even though you might be diving double 130s and 800 psi could be an entire dive's worth of gas. That certainly was not reassuring...and my buddies really didn't like it much either.

Determining time is very easy. Monitor your gas every 5 minutes. There is no need to check your gas more often than this. Before you look at your gauge (which should be a *backup* to your brain), decide how much gas you should have remaining. During that 5 minute period, if you have used 200 psi, and you have 1000 psi left, you know that, at the depth you are at, you have ~25 mins until you drain your tank dry. This is no different than the information you'll get from your AI computer.

Same information, only now you have engaged your brain and made yourself more aware of your dive and profile (and saved yourself a few hundred bucks!)

I just like the additional piece of calculation.

That's really the answer. There are other ways to get the same information, but you like it being fed to you.

My AI has also been a teaching tool. Since my AI provides me with info regarding my remaining psi and a timer "countdown", it has helped me better understand how all these variables affect my diving.

I used to believe this, too. In reality, I was becoming *less* aware of how the variables affected my diving because the computer was feeding it to me. Once I started doing the tracking myself, I became more disciplined, and had a better handle on what was going on during my dive. This was a case of Uncle Pug's "Computers Rot Your Brain" which I do not normally agree with, but experienced in this case.

I often do extensive post dive analysis to determine my SAC rate at various stages of the dive (where I may be on different gases, so my computer's "average depth" becomes useless as well) by making mental checkpoints. That type of information will give you much more useful feedback for planning future dives.

So I challenge you again....what information does the AI give you that cannot easily be obtained in other ways?

 

[nvert]

I clearly stated what I find "useful" about my AI. If you can't see that another is capable of learning differently from you than there is no sense in further pursuing your *challenge* which to me is now beginning to sound as an attack.

No other thing but experience is going to help one improve. The computer, the gauges, the watch all provide data but, you're right, you need to first understand that data and in order to aptly apply it to understanding/assimilating it into a form of knowledge that will improve your learning. My doc confirmed I do not have Brain Rot but maybe he's wrong since he's using CATSCANS, ELECTRODES and X-Ray goggles.

Looking over your profile - tech diver, tech certs, etc - it's apparent that you have a very different approach to diving than most and I respect that. I don't dive doubles nor am I interested in going beyond rec limits. That may change with time but for now that's not my goal. I enjoy my AI and the info it provides me with.

BTW, I have not lost any joy during a dive by being wrapped up in how much time my computer says I have left. I'm not a slave to it but maybe I'm just fortunate enough to have the means to spend the extra $$$ on something I have found "useful".

So, now I challenge you to let this go.

 

[Rick Murchison]

When I first started diving the "SPG" was "check it before the dive," and when it started getting hard to breathe . I've gotten a little more conservative in my old age and now I want one SPG per bottle (or manifolded set) that's reasonably accurate (to the nearest 100 psi). More than one is just adding failure points unnecessarily. Whether it's electronic or analog doesn't matter to me. If one fails it's time to turn the dive, and I'm assured of plenty of gas to do that safely, 'cause I know how much I had when it failed and because we do our gas planning.
The closest thing to a failure I've ever had was most of the needle falling off an analog gauge; never had an electronic one fail yet (I dive a Cobra routinely).
Rick

 

[CompuDude]

I have a wireless AI on my wrist. Nice to have the number right there. I know it anyway, but it's still nice to have it right in my face. I have an analog SPG as a backup, and I check it periodically to keep in practice should I decide to change computers at some point. All points covered. Yes, it cost a bit more, but if you're that worried about cost you're in the wrong sport.

BS about a stubby little transmitter on your first stage (in addition to the regular SPG) adding points of failure is just that. (It's possible to consider it for caves and wreck penetrations, perhaps, but for any open water dive, regardless of depth, I consider it to be a non-issue.)

 

[Quarrior]

I have a wireless AI on my wrist. Nice to have the number right there. I know it anyway, but it's still nice to have it right in my face. I have an analog SPG as a backup, and I check it periodically

This is the same setup I dive.

 

[ArcticDiver]

...BS about a stubby little transmitter on your first stage (in addition to the regular SPG) adding points of failure is just that....

This whole idea of points of failure is not very useful anyway. As promoted and used it doesn't take into consideration probability of that failure. So, an item may be a point of failure but the probability of that failure occuring is nil is a concept that is all but ignored.

In fact the item on any dive that has the highest probability of failure is the content of the diver's skull. And that is inferred since accurate information and analysis on numbers of failures and their causes is not available.

 

[limeyx]

...

BS about a stubby little transmitter on your first stage (in addition to the regular SPG) adding points of failure is just that. (It's possible to consider it for caves and wreck penetrations, perhaps, but for any open water dive, regardless of depth, I consider it to be a non-issue.)

But where is the sense saying "well, normally I use the AI but now that I'm going into this really dangerous cave/wreck, I'm suddenly going to get rid of that and use just an analog SPG"

Why then not just use the analog SPG all the time so you actually have some practice with it before going into the cave or wreck?

 

[Soggy]

Why then not just use the analog SPG all the time so you actually have some practice with it before going into the cave or wreck?

Exactly! This is the principal of primacy that few people seem to consider as part of their diving. If it works for high-level technical diving, then it will certainly work for easy-breezy recreational diving. Why not make the same optimizations to one's recreational diving that are made to technical diving operations, especially when you don't actually lose any functionality?

 

[CompuDude]

But where is the sense saying "well, normally I use the AI but now that I'm going into this really dangerous cave/wreck, I'm suddenly going to get rid of that and use just an analog SPG"

Why then not just use the analog SPG all the time so you actually have some practice with it before going into the cave or wreck?

Did you see my whole post?

"I have an analog SPG as a backup, and I check it periodically to keep in practice should I decide to change computers at some point."

Law of Primacy is a valid point, but fails in that primacy is long since shot. I was diving with an AI wrist computer long before I considered DIR. And technically, considering I was trained oh-so-many-years ago with an old school console, so having to check the same general vicinity for my SPG is actually how I learned in the first place... it's the wireless AI that's new.

Aside from all that, but how many times do I read here that you really shouldn't have to check your SPG more than a couple times in a dive, and mostly to confirm what you should already know. We're supposed to know our PSI without even looking, within a couple hundred pounds based on experience and knowledge of our breathing rates. So how does an additional readout of the same information hurt anything?

The only reason I see NOT to do this is cost/expense (which is valid for some but I have already long since spent the dough, so that's a non-issue for me until it comes time to buy a new computer) and [what I consider to be] excessive worrying about adding an incredible unlikely point of failure.

 

[limeyx]

Did you see my whole post?

"I have an analog SPG as a backup, and I check it periodically to keep in practice should I decide to change computers at some point."
...

So the analog SPG works just fine for you, so why add anything else since you dont need it, right?