Will Air Integration in dive computers replace the SPG?

[guyharrisonphoto]

we're not talking about turn pressure (which you can set to alert at any pressure you want) or max depth (determined not by AI but other factors like mix and NDL). We are talking about what AI can offer with regard to a reserve for a gas sharing ascent--and I in particular am a rec diver with that perspective.

I may need to clarify how the ATR works. The "reserve" is not what you begin your ascent with, it is what you will have on the surface. Take the 500psi example. If I am at 100', the computer will not send me up when I reach 500 psi. The computer might send me up (depending on my real-time consumption) when I reach 800 psi, because it is predicting, based on real-time dive consumption, that it will take me 300 psi to reach the surface. Double that means 600 psi for two of us to reach the surface. So, the computer gets us both up with a 200 psi cushion. This might seem slim, but the computer is predicting a normal ascent rate and a safety stop. In reality the cushion is pretty substantial if you omit the stop and ascend faster.

This is self-adjusting for depth and effort. The deeper you are and/or more you are working,, the more you are consuming, and the computer will send you up with more in your tank.

This could be adjusted pretty easily for a "rock bottom" calculation tied to real-time dive conditions. For example, a calculation based on double your current consumption, getting two of you to the surface with, say 200psi or whatever reserve you set, perhaps even with adjustable parameters for the ascent. That, seems to me, would be better than a pre-dive estimate based on assumptions that might or might not apply on a given dive.

 

[Bennno]

we're not talking about turn pressure (which you can set to alert at any pressure you want) or max depth (determined not by AI but other factors like mix and NDL). We are talking about what AI can offer with regard to a reserve for a gas sharing ascent--and I in particular am a rec diver with that perspective.

I may need to clarify how the ATR works. The "reserve" is not what you begin your ascent with, it is what you will have on the surface. Take the 500psi example. If I am at 100', the computer will not send me up when I reach 500 psi. The computer might send me up (depending on my real-time consumption) when I reach 800 psi, because it is predicting, based on real-time dive consumption, that it will take me 300 psi to reach the surface. Double that means 600 psi for two of us to reach the surface. So, the computer gets us both up with a 200 psi cushion. This might seem slim, but the computer is predicting a normal ascent rate and a safety stop. In reality the cushion is pretty substantial if you omit the stop and ascend faster.

This is self-adjusting for depth and effort. The deeper you are and/or more you are working,, the more you are consuming, and the computer will send you up with more in your tank.

This could be adjusted pretty easily for a "rock bottom" calculation tied to real-time dive conditions. For example, a calculation based on double your current consumption, getting two of you to the surface with, say 200psi or whatever reserve you set, perhaps even with adjustable parameters for the ascent. That, seems to me, would be better than a pre-dive estimate based on assumptions that might or might not apply on a given dive.

When I read this I feel like we're not even in the same sport.
Diving within NDLs is very straight forward and is super easy to plan.
I don't get what the point of all of this is. IMHO you guys are unnecessarily complicating stuff.
What ever happend to: set a max depth, set a max time, set a turn pressure and be back on the boat with 50 bars left.
I never once heard that you need a computer to tells you when to ascend because your getting low on gas. It doesn't get more basic than this.
What's next? A computer that tells me when I get hungry?

If you feel you need these functions you should really get some better training. It really doesn't get any easier than this.

 

[dmaziuk]

When I read this I feel like we're not even in the same sport.

Did he say anywhere in his post that he stays down until his computer tells him his out of ATR? What I read is a description of what you can program the computer to do. I find it mind-boggling that someone can plan their dive that way, program that plan into their computer, and therefore "you should really get some better training". Really really?

I feel like we're not reading the same letters. Or maybe the same letters but not the same sentences.

 

[Bennno]

If you pay just a little bit of attention while you're diving (which you should anyway), these functions are useless, IMHO.

 

[AJ]

Did he say anywhere in his post that he stays down until his computer tells him his out of ATR?

No he did not, so what is the point of programming/using a computer this way? Seems unnecesarily complicated to me.

 

[CuzzA]

WAI dive computers should not change anyone's approach to diving. All it does is put the same information in a different location.

For example:

I plan a buddy dive to 100 fsw. Before I dive I will calculate mine and my buddies rock bottom reserve. To make the math simple we'll assume each of us have SAC rate of 1 and I'm using a jacked up 112 filled to 3100 psi giving me ~130 cu ft. Based on this information I can calculate a safe accent including all stops and the number will be 1200 psi. That is the number I should reach the surface with.

Now location, I can either try to remember that number, not much of a problem, but perhaps on the 4th dive of the day there's a risk of confusing it with a previous calculation or a miscommunication with my buddy, so perhaps it would be best to write it on a slate OR I can program it into my computer. Same info, different location.

Now, on this dive we're actually going to swim out from the entry point and swim back. So based on my reserve I know that gives me 950 psi out and 950 psi back. So again, I can try to remember that, right it on a slate, OR program it into my computer. Same info, different location.

Finally, we start the dive and I want to check my gas. I can do some math like kevrumbo has suggested throughout this thread, I can check an SPG bolt snapped to my waist, OR I can look at my wrist DC. Same info, different location.

So you see, it's just another place to view the information. I don't know why so many have a problem with that. Clearly the WAI is more convenient and that's all I've ever said it was.

In all honesty and I've mentioned it before, I rarely fly the DC based on the ATR. I treat WAI just as I would an SPG with the added benefit of programming my or me/buddies rock bottom reserve and turn pressure. I will continue to do it that way for now.

However, on a Gulf drop over a patch reef ledge where I'm not going anywhere but down and up, I'll use the ATR to gauge how much time I have left to do whatever it is I'm doing. Gives me a good idea in "time not just PSI" if I should go after that last fish or not. Prior to using ATR, I made what I think was a bad judgment call and shot a fish when I shouldn't have. It was uneventful, but looking back I dipped into some reserve gas.

Nevertheless, aside from convenience here's where I see some future benefits to WAI and that is the ability to monitor your buddy's gas and vice versa. On the fly calculating of both divers gas I think is a great feature and it insures both divers should have enough reserve gas to safely make it to the surface in the event one diver has a complete gas loss at depth. A much better system than hoping your buddy is holding your reserve.

I will say that I think there's a lot to be excited about with diving technology. Some have mentioned there's been no change to WAI for 20 years, yet I did a little searching the other day and have found new patents published as recently as 2014. IIRC, one patent I read about included a gauge on the transmitter for redundancy. We've seen the release of a system where you can see your buddies air too, I don't know if it calculates ATR for both divers, but I'm sure one day it will. The transmitters can now reach ~330 ft. I'm willing to bet they couldn't do that 20 years ago.

We're also seeing diver location data incorporated into the computer. That's freaking awesome. Buddy separation/lost diver(body)? No problem, we can find each other. Can't find the boat/anchor line? No problem, here it is... Head this way.

I get some people don't like tech, but that's awesome to me and will certainly save lives in the future. It may not matter to some people because they are the best diver in the world, but unfortunately buddy separation and OOA accidents still happen.

 

[Lorenzoid]

Maintaining a larger gas reserve at deeper depths? Of course. That's what some people call a no-brainer.

If you need a computer to do this for you there is a problem somewhere.

This goes back to the idea that one doesn't need a computer to compute NDLs, either. You can use a table. For rock bottom, I use a slate on which I have written three or four depths and the corresponding "rock bottom" pressures I need to have in order for my buddy and I to ascend safely, taking into account increase in SAC due to stress, etc. But that is based on a conservative estimate of our SACs. A computer with WAI that monitors both divers in a team could use their real-time SACs to estimate rock bottom at the current depth. The real-time computation of SAC could be thought of as giving the diver "more air time" than if estimated manually, just as a computer can be thought of as giving the diver "more no-deco time" than if estimated manually (using a table). In the end, it's all about leveraging technology to maximize one's dive time. Achieving maximum dive time while taking no more decompression precautions than required to avoid the bends and while carrying no more air than required to avoid drowning is an important goal to some people, it seems. Some people prefer to get as close to the edge as possible. Others are okay with sacrificing dive time for safety margin.

 

[dmaziuk]

No he did not, so what is the point of programming/using a computer this way? Seems unnecesarily complicated to me.

Correct, but by that logic what is the point of having an ascent rate alarm, or a planned depth alarm? Or, for that matter, an NDL readout? You can track all of those without a computer too.

 

[Bennno]

We're also seeing diver location data incorporated into the computer. That's freaking awesome. Buddy separation? No problem, we can find each other. Can't find the boat/anchor line? No problem, here it is... Head this way.

That would be a useful thing but this has absolutely nothing to do with AI.

I get some people don't like tech, but that's awesome to me and will certainly save lives in the future.

No, you don't understand. It has nothing to do with 'liking tech'. I have a smartphone, a tablet computer and all that crap. I don't use AI (anymore) because it's an expensive toy that has no usefull functions.
Let's not start this all over again.

 

[Ghosty]

Excuse the dive computer n0ob question. Do the Oceanic DC's dynamically display the lower number it calculates between ATR & DTR? Shouldn't the DTR always be lower since it takes the ATR then also adjusts down (safer or more cushion) for oxygen/nitrogen absorption? Is this user settable? I have the Aeris A300 but am just starting to play around with it. Yes I have the PDF manual, in the middle of reading it.