question about AI computers

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donnad

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Richmond, tx
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hi, hubby and i haven't yet purchased computers, but hope to do so in the not too distant future. question.....we are not air hogs at all and are usually the last or near last in a group to come up. have been diving a couple of years now. husband is thinking air integrated is better because it will be basing its data on your actual air consumption and so if you are a conservative air user, you'll get more bottom time because you'll be absorbing less nitrogen than someone who uses their air more quickly. am i making sense and is this a consideration? tell me what you feel are the benefits of air integrated. and also, if i understand correctly, you can have air integrated, but still have an SPG hooked up so if your computer fails you still know how much air you have. thanks for your help.
 
No, it's not a consideration.

Your nitrogen loading is determined by the pressure, and the partial pressure of nitrogen in your lungs. When you are breathing from a tank your lungs will contain a certain % of nitrogen and that won't really change. So nitrogen loading it is only determined by depth.

In other words, someone who breaths slowly and soneone who breaths quickly will have the same nitrogen loading if they are breathing the same gas at the same depth.
 
Nitrogen absorption is based on depth and time, not the amount of air you use. When you descend breathing air, the ambient pressure increases. We know from Dalton's Law that the nitrogen partial pressure at 2 ATA is 2x greater than the partial pressure on the surface. The longer and deeper the dive, the more nitrogen you will load in your body tissues.
 
One correction, using less gas does not reduce the amount of nitrogen loading during a dive. The nitrogen loading is a function of the ambient pressure of the water at a given depth and the percentage of nitrogen of the gas which one is breathing.

An advantage of some of the air intergrated computers is that, based upon the breathing volume and rate at a given time, the computer will indicate how much breathing gas you have remaining at that respiratory rate at that depth.

Yes, a diver can have an air intergrated computer and an analog SPG attached to the first stage (most modern 1st stages have 2 HP ports).

In my opinion, an air intergrated computer is advantageous in the fact that it removes one more piece of gear with which to contend. If one is wearing a computer that is not intergrated, two movements are required to check the depth/dive time and the remaining air pressure. With an air intergrated computer, one views both pieces of information at the same time.

An alternate analog SPG/depth gauge when coupled with a dive watch adds good redundancy to one's dive.

IF: you plan your dive based on tables/wheel and your computer becomes inoperative, you can revert to the analog gauges and watch and continue the dive IF you have not exceeded your dive plan based on a square or multi-level profile.

the K
 
ok, thanks for the speedy info! you guys/gals are awesome! i don't like to buy things twice, so i want to carefully consider what kind of computer i want. doesn't sound like air integrated is that much of an advantage really then, huh? and i understand you can get a darned good non-air integrated computer for even like $300 or so, right?
 
I would not have anything but AI. I made the mistake of buying my kid a non-AI and will soon have to buy him another computer. As for redundancy, I don't see the need for an spg. If the computer fails, the dive is over then and there. Being able to see remaining air adds nothing...unless you have a deco obligation ... in which case, you will need a backup computer.
 
ItsBruce:
I would not have anything but AI.

And I wouldn't have one.

ItsBruce:
As for redundancy, I don't see the need for an spg.

Agreed. You don't necessarily need redundant gauges for the tank on your back.


ItsBruce:
If the computer fails, the dive is over then and there.

If the SPG fails, dive is over

ItsBruce:
Being able to see remaining air adds nothing...

I disagree. being able to see air remaining can reduce panic. You'd have to be a pretty cool customer to realize near the end of your dive that you don't know if you've got enough air to exit. The fear of the situation is probably worse than the reality.


ItsBruce:
unless you have a deco obligation ... in which case, you will need a backup computer.

Or the ability to properly plan a dive.
 
ItsBruce, i'm curious, please elaborate on your feelings about not having non-air integrated computer. i certainly want to make an informed decision when i get a computer, so i'd like to hear your experience. thanks, donna
 
Personally I don't see the point of an AI computer--it just seems like another addon gimmick for people to buy. I would much rather use a standard SPG.
 
Up untill two days ago I had an Air integrated computer, I loved it dearly (may it rest in peace). The only real advantage to haveing air integrated computer is that it calculates air time remaining, so you can see whether or not you have more air or no deco time remaining. Really though, you should know about how long your air is going to last you, the computer is fairly easy to trick. The disadvantage is that if the computer fails you're left with absolutely nothing, if it starts making incorrect calculations for airco and you go by it you're doomed (same thing for deco though, so not much of a point). If the computer meets it's death it is far more expensive to replace. Personally, I like SPG's, they don't have batteries.
If you do end up getting an air integrated computer I would suggest getting one that attaches to your first stage via a hose, I don't trust transmitters and know several people who have tried them and learned not to trust them with good reason.
The only true advantage I can see to an air integrated would be if the computer had an analyizer (i wish i could spell) for nitrox. That would rule.
My two cents.
 
https://www.shearwater.com/products/peregrine/

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