Shearwater Perdix AI

[scubadada]

It takes longer to describe & explain the process below than to actually do it -which is why those without the patience & motivation to comprehend & learn, purchase the quick solution extravagance of wireless AI.

I have a full 200bar AL80 tank and consume 30 bar in five minutes at 18 meters depth; therefore after five minutes I know have 170bar remaining (200 - 30 = 170):

So five minutes elapsed time and my SPG should read 170bar -check the SPG! It does.

Another five minutes for total ten minutes elapsed time and my SPG should read 140bar -check! It does.

Fifteen minutes elapsed time and my SPG should read 110bar -check! It does.

Twenty minutes elapsed time and my SPG should read 80bar -check! It does, and then start a multi-level ascent to the shallows around 9 meters where I use 20 bar in five minutes. Finally ascend to complete a three minute safety stop, surface & inflate bcd, and I know my SPG will show 35 to 40bar remaining. . .

And so begs the question: do you really need the expense of wireless AI to tell you what you already know about your consumption rate (or should be motivated to learn & figure out in the first place), over the practical & economic utility of a basic bottom timer/dive computer and SPG? Is it really so hard to perform the subtraction arithmetic above -both on pre-dive planning & real-time during the dive- without an AI feature?

[Especially for all Metric System users with typical nominal pressure Sac rate values of one to two bar per minute, you don't need the Air Time Remaining functions of an AI feature: In other words, how difficult is it to do in your head multiples of 1 bar/min or even 2 bar/min??]

You have made this exact same post an infinite number of times. That does not make it any more applicable to the vast number of divers who do not follow your methods. Good for you, no reason to continue to criticize others.

 

[Kevrumbo]

You have made this exact same post an infinite number of times. That does not make it any more applicable to the vast number of divers who do not follow your methods. Good for you, no reason to continue to criticize others.

We've all been given the instruction and basic instrumentation to perform this fundamental and vital task in our beginning open water course. Some divers need an "infinite number of times" to review it and learn how to apply it again. . .

And the point is that no matter how quick and easy it is, on land, it will always be harder when (possibly) narced and never as quick (or as low of a task load) as letting a computer do it for you.

For someone who is completely dependent on their computer to calculate their NDL (or their mandatory deco) for them, what argument can you make that that is okay, but letting it calculate GTR is not okay?

If you want to have people not rely on their computer for either thing, then we're back to having a mechanical depth gauge, a physical SPG, and a wind-up dive watch. If that's how you want to dive, that's fine. I certainly have no interest whatsoever in getting you to dive differently. But, dang! Recognize that the rest of the diving world has moved on and embraced newer technology. Technology that has proven itself to be more than adequately reliable and precise (and safe) over a period of years of use. Give it a rest on getting people to try and go back to old tech ways of doing things.

If the current, modern ways are not safe, please provide actual data, not a list of threads that you think support your position and would require reading hundreds of posts just to have a discussion about it. Can you provide ANY data to support an assertion that GTR calculations in a wireless AI computer system have resulted in any number of deaths? If people aren't dying (or getting hurt) from using it, what is the problem? Just that you don't think it's worth the money and you're pissed that other people are spending their money in a way that you wouldn't?? Crikey! The number of times I've seen people rant against other people buying something where the root of their argument really and ONLY boils down to the ranter doesn't think the item under discussion is worth the price! That is purely a budget decision, which is none of your business unless it is you that is debating making the purchase for yourself.

Or maybe you're pissed that other people don't have to learn to do the math like you did? Do you think people should have to learn how to change and gap a spark plug before they drive a car, too?

If you're so narced that you can't comprehend or account for what a simple SPG is telling you, then you should abort the dive. Purchasing a wireless AI isn't going to solve the root problem either.

So what you are saying is you are depending on a electronic device (watch or bottom timer) to tell you when it is 5 minutes and not 4 minutes or 6 minutes.

You don't need to depend upon a separate battery powered digital wireless transducer/transmitter to give you the same instrumentation info that a bottom timer/SPG does. . .

But you still check your SPG, don't you? If yes, then you're the one conflating the issue: one argument is hoseless vs hosed SPG, another one is guesstimated ATR vs actual tank pressure, and a different one still is mental arithmetics vs a measuring device. Or is your argument: do I really need the expense of an SPG when I already know what my gas consumption rate should be and am capable of performing kindergaden-level addition in my head.

It's a rhetorical question: can you do arithmetic involving multiples of 1bar/min, or at most 2bar/min without AI, or even a calculator app on pre-dive gas planning? Sure you can! All you need is a SPG to confirm what you already know. . .

 

[admikar]

End of my post first: thank you SB for letting me pick up on your collective brain! Why?
When I started diving, I had no intention in going tech,just like @stuartv , hell, even BP&W was too tech to me. Now I dive BP&W, I've dived doubles,DS and even some deco (with reading on deco theory, planing,and redundancy). Few weeks ago, when PAI was announced I was resolute NO, I don't need it. Some people are for it, some are against. Reading all the posts, I am still at same point, but open to see what will come out of all of this. If people more experienced than me on this board, conclude that AI is good after some gestation period, then I will go for AI. If not, nothing changes for me. One thing I want to ask from all that participate in these threads on AI is, respect opposite choice.

Tech divers all over the world trust Shearwater computers every day to get them out of the water without getting bent. Deco computations are an inexact and very complicated science. And yet people trust Shearwater (and other computers) to do it and without second-guessing the computer's results in midwater. Gas Time Remaining computations are trivially simple, in comparison, when you're talking about only using a single gas supply. Why would you trust a SW computer to get you out of a 200' trimix dive with deco, without getting bent, and not have at least as much faith in it to get you out of the water without running out of gas at the end of a single tank dive??

Car analogy: when ABS and stability control became available, a lot of people bought a lot of fast cars, without understanding on working principles of those systems. It resulted in a lot of junk piles of fast cars.
Educated divers are OK,IMHO.Problem with GTR (on SW,as a tech computer) is that a lot of FIGJAM or IDFC, or just plain two day course divers will buy this computer (for all it's tech hype) and try to ride it to the limit. At those limits, statistically, is when smelly stuff starts to hit a fan. Some people then will start to blame computer for their shortcomings. And that is when it starts to complicate ours diving.

 

[Joneill]

It takes longer to describe & explain the process below than to actually do it -which is why those without the patience & motivation to comprehend & learn, purchase the quick solution extravagance of wireless AI.

I have a full 200bar AL80 tank and consume 30 bar in five minutes at 18 meters depth; therefore after five minutes I know have 170bar remaining (200 - 30 = 170):

So five minutes elapsed time and my SPG should read 170bar -check the SPG! It does.

Another five minutes for total ten minutes elapsed time and my SPG should read 140bar -check! It does.

Fifteen minutes elapsed time and my SPG should read 110bar -check! It does.

Twenty minutes elapsed time and my SPG should read 80bar -check! It does, and then start a multi-level ascent to the shallows around 9 meters where I use 20 bar in five minutes. Finally ascend to complete a three minute safety stop, surface & inflate bcd, and I know my SPG will show 35 to 40bar remaining. . .

And so begs the question: do you really need the expense of wireless AI to tell you what you already know about your consumption rate (or should be motivated to learn & figure out in the first place), over the practical & economic utility of a basic bottom timer/dive computer and SPG? Is it really so hard to perform the subtraction arithmetic above -both on pre-dive planning & real-time during the dive- without an AI feature?

[Especially for all Metric System users with typical nominal pressure Sac rate values of one to two bar per minute, you don't need the Air Time Remaining functions of an AI feature: In other words, how difficult is it to do in your head multiples of 1 bar/min or even 2 bar/min??]

How about us new rec divers who don't yet fully understand our "normal" SAC? Or when you have an off day, are anxious/less relaxed for some reason or there are stronger currents that make you exert more? I turn my dives at a preplanned pressure and typically start an ascent at 700 psi, so I check my SPG periodically to see how I'm doing. For me, having the tank PSI on my wrist with all of my other pertinent dive info is more convenient that checking my SPG (though I'll keep as a backup). In addition, seeing current SAC throughout a dive will help to understand how my air consumption is affected by different conditions. The GTR is of less concern to me at this point as I'm used to reacting to tank pressure.

 

[Kevrumbo]

How about us new rec divers who don't yet fully understand our "normal" SAC? Or when you have an off day, are anxious/less relaxed for some reason or there are stronger currents that make you exert more? I turn my dives at a preplanned pressure and typically start an ascent at 700 psi, so I check my SPG periodically to see how I'm doing. For me, having the tank PSI on my wrist with all of my other pertinent dive info is more convenient that checking my SPG (though I'll keep as a backup). In addition, seeing current SAC throughout a dive will help to understand how my air consumption is affected by different conditions. The GTR is of less concern to me at this point as I'm used to reacting to tank pressure.

Fair enough premise for novice recreational divers. If you're still learning about Sac rate and worried about times of increased consumption during exertion, then take your SPG and clip it to your chest/shoulder D-ring where it is visible at a glance.

You don't need wireless AI as an expensive training wheel. . .

 

[drrich2]

Is it that hard to perform simple subtraction arithmetic over depth & time starting with an initial pressure fill that you need AI?

For me, yes. This sounds to me like situational awareness, navigational ability, mathematical calculations, writing effective answers to open-ended essay questions, grasping 3-dimensional relationships & probably many of things. Some people, for whatever reasons whether innate or acquired, have a knack for it, and as it seems natural to them, some feel it should be natural for others of near average or higher intelligence, if they would...

1.) Just give it a try.
2.) Not give up and quit soon.
3.) Have a positive attitude about it.

And there are people who, for whatever reasons whether innate or acquired, have an 'anti-knack' for it, find it unnatural and tedious to do if they can even get started (e.g.: the kid with stalled brain looking at an essay question on a test), and 1.), 2.) & 3.) are not going to lead to rapid, practical fluency.

Some people don't benefit from A.I. Some people do. Making them feel bad about not multi-tasking another thought thread of mental math on top of everything else they're juggling is not going to change that or make it better.

How many times on ScubaBoard have newbies been discouraged from taking a camera with them until many dives down the road because it might distract them? Do we not learn in Rescue Diver courses, or from practical real world experience, that for many people diving (even in benign conditions) often task-loads us more than we realize, such that tossing a new problem in the mix can have a worse impact than one might've expected?

If using A.I. frees up a little mental bandwidth while maintaining gas supply & rough estimated time remaining, that's not a bad thing.

Richard.

P.S.: Related to the A.I. topic in a peripheral say - I'm guessing someone else has already stated the obvious, but I'm not pouring back over the thread right now so at the risk of redundancy, I'll risk it...arguments against ATR/GTR, that it's not useful because it changes with depth, for example...I don't read anybody claiming that about on-the-fly NDL figures offered by dive computers.

 

[Joneill]

Fair enough premise for novice recreational divers. If you're still learning about Sac rate and worried about times of increased consumption during exertion, then take your SPG and clip it to your chest/shoulder D-ring where it is visible at a glance.

You don't need wireless AI as an expensive training wheel. . .

First of all, I do clip my SPG to my upper left chest D-ring - have done so since day 1 per my instructor's suggestion. However, I really like the idea of being able to monitor tank pressure, depth, NDL and all other dive info with one glance at my wrist which is already out in front in my field of view. I also like that it will automatically record start and end pressure for me for my log and analysis later.

Why do you have a problem with other people having a different POV than you and why do you care what I spend my money on? I'm an educated adult and I make decisions based on what makes sense to me and what I can afford - to me, the Perdix AI is not expensive at all.

So here's some advice for you - stop telling us to do what you think is best for you - I, for one, don't care what you think and would never take advice from someone as narrow minded and condescending as you are coming off as in this thread.

 

[Kevrumbo]

First of all, I do clip my SPG to my upper left chest D-ring - have done so since day 1 per my instructor's suggestion. However, I really like the idea of being able to monitor tank pressure, depth, NDL and all other dive info with one glance at my wrist which is already out in front in my field of view. I also like that it will automatically record start and end pressure for me for my log and analysis later.

Why do you have a problem with other people having a different POV than you and why do you care what I spend my money on? I'm an educated adult and I make decisions based on what makes sense to me and what I can afford - to me, the Perdix AI is not expensive at all.

So here's some advice for you - stop telling us to do what you think is best for you - I, for one, don't care what you think and would never take advice from someone as narrow minded and condescending as you are coming off as in this thread.

If all you have is feigning indignation as your end-all excuse by playing the rebuttal, "It's My Money -I can spend it as I want, why do you care?. . .", then you're right! You get what you deserve . . .You get what you pay for.

And I don't have a problem with an objective but different POV: Richard @drrich2 above has a honest reasonable explication and rational justification of both sides of the argument. . .

 

[Joneill]

If all you have is feigning indignation as your end-all excuse by playing the rebuttal, "It's My Money -I can spend it as I want, why do you care?. . .", then you're right! You get what you deserve . . .You get what you pay for.

And I don't have a problem with an objective but different POV: Richard @drrich2 above has a honest reasonable explication and rational justification of both sides of the argument. . .

Exactly - what I get is what I want and am willing to pay for. What do you mean by I get what I deserve? For me, what I get is a nice upgrade over just having my SPG: the ability to monitor my tank pressure on the same screen that contains all of my other relevant dive data. I also get real time view of my SAC and automatic logging of that data as well as start and end pressure for post dive log and analysis. How is that a bad thing as you seem bent to want to make everyone feel is the case ? For me, that is well worth paying for.

Sorry if a lowly rec diver having that POV is a problem for you, as seems to be the case. No one said you have to agree!

 

[Kevrumbo]

Exactly - what I get is what I want and am willing to pay for. What do you mean by I get what I deserve? For me, what I get is a nice upgrade over just having my SPG: the ability to monitor my tank pressure on the same screen that contains all of my other relevant dive data. I also get real time view of my SAC and automatic logging of that data as well as start and end pressure for post dive log and analysis. How is that a bad thing as you seem bent to want to make everyone feel is the case ? For me, that is well worth paying for.

Sorry if a lowly rec diver having that POV is a problem for you, as seems to be the case. No one said you have to agree!

You get what you deserve . . .As long as wireless AI works, is reliable & safe for you and you're having fun dives with it -->then that's all that really matters!