Air integrated computers and drysuit diving

[Pegger]

I really like my Wisdom air integrated computer but since I got my first drysuit last year I'm not sure if it's a good combination as the added air required for the drysuit works against my safe dive time. Most people have had a wrist mounted computer, not air integrated.
Any advise would be appreciated!!

Thanks in advance,
Steve

 

[Bubbletrubble]

Steve, are you being serious about this?
1. You do realize that you shouldn't have to put any extra air in your suit when you ascend, right?
2. Even if you wanted to add an extra oh-$@#*-I-need-to-add-air-to-my-drysuit cushion to your gas management, just read the psi display. You should know what your Rock Bottom for a given depth is. You should also have a general idea about your RMV/SAC rate.
3. If you don't know about RB, read Lamont's Gas Management article.
4. Use your Wisdom...and be happy.

Have fun and dive safe.

 

[Riger]

I really like my Wisdom air integrated computer but since I got my first drysuit last year I'm not sure if it's a good combination as the added air required for the drysuit works against my safe dive time. Most people have had a wrist mounted computer, not air integrated.
Any advise would be appreciated!!

Thanks in advance,
Steve

Not sure if i have the wrong end of the stick here but, using air for the purpose of buoyancy in a dry suit should be the same as using air for the purpose of buoyancy in a BCD.

Best Regards
Richard

 

[CalgaryDF]

Echoing what the other posters have, I would think that the air used in your drysuit would be minimal in comparison to what you breath. Also, If you are diving with a non AI computer you will still be limited by air the same as if you have a AI computer.

 

[Pegger]

Echoing what the other posters have, I would think that the air used in your drysuit would be minimal in comparison to what you breath. Also, If you are diving with a non AI computer you will still be limited by air the same as if you have a AI computer.

I was referring more to my safe dive min. as displayed rather than my quantity of air remaining.
We were on a large wreck a couple of weeks ago where it was about 15' from the mud to the deck and every time we made this change in depth I had to vent/add air which cuts into safe dive min. on a integrated computer where it would not if it was not integrated. Yes or no?

Steve

 

[NorthWoodsDiver]

Air integrated computers make an attempt to calculate how much air you breath and at what rate, this we call your SAC rate. Your computer is going to be calculating this on a constant basis so every time you add air to the suit the computer thinks your breathing heavier and using more air so its going to change all the readouts to compensate for what it perceives as an increased SAC even though your SAC is not increasing.

Does that make sense?

The important thing to learn is that a computer has no brain and its no able to think for itself. However you should have a brain or you wouldn't be alive so you need to educate yourself on how to not rely on the computer if that is something you currently do.

Best advise I could give would be to remove that computer and use a simple pressure gauge with a bottom timer for a while.

 

[rmc77]

Steve,

I believe I understand what you're saying.
Your computer calculates the your "safe dive min" based on your SAC. In other words, based in the remaining air, pressure and depth the computer extrapolates a curve and gives to U how many minutes you still have of air if you keep that SAC constant - the so called "Safe Dive Min". So, every time you need to add air to your suit, it will increase your SAC momentarily and decrease your "Safe Dive Min", right?
But, even though I believe I understand what you're saying, I don't see what's the difference when diving only with a BCD on... 'Cause you have the same issue there, every time you add air to the BCD it will alter your SAC.
And as someone mentioned, that's a momentary increase in SAC and, in average, if you don't have buoyancy issues or defective BCD/ Dry Suit, the amount of air used will be minimum compared with what you will breath. So after a couple of moments, the "Safe Dive Min" will go up again...
At least that is my experience with air-integrated computers...

Cheers

Rafael

 

[Riger]

One could go a step further and say that because the air you use for buoyancy is also the air you rely on for breathing, the computer considers your occasional additional use of air for "buoyancy" purposes and includes that in its calculations for your "Safe Dive Min", it can therefore reasonable predict (if your usage remains similar for both breathing and buoyancy) your average future additional use of air - thus providing you with an accurate "Safe Dive Min" that includes your breathing and buoyancy usage.

One would however hope that (1) you do not depend on this data from the computer to make big choices (ascent planning, entering a swim through, wreck or any other overhead environment) and (2) that the computer takes the occasional purge and inflation [-]requirements [/-] events into account and does not penalise you for this (measurable) additional activity other than the fact that there is now less air in the combined supply.

Best Regards
Richard

 

[mikeguerrero]

I also use air-integrated computer and I use Argon as an injection to my drysuit instead of my air tank. In this matter, I do not confuse my computer into calculating my correct SAC rate.

My Argon bottle has it's very own 1st stage regulator and is not connected to my main regulator.

MG

 

[The Kraken]

Pegger,

I'm not sure, but I think you may have a mistaken concept how your air intergrated computer works.

Your "safe dive time" given to you by your computer is a dynamic function that is constantly recalculated based upon the sampling rate of your PDC.

This calcualtion incorporates all of the breathing gas lost from the tank, both the gas you breathe and that gas used to inflate your dry suit.

The amount of gas required to inflate your dry suit is, for the most part, quite insignificant.

I've never thought about doing any calculations on the amount of gas required to manage a dry suit during a dive, but I dare say that it would be less than 2 cubic feet.

I think your concerns are unwarranted.

the K