Will a liberal computer ever go into deco before a more conservative one?

[scubadada]

Performance on a 1st dive is both interesting and useful, however, performance on multiple dives is much more important. This kind of data is rarely available. There is some information available from Scuba Diving Magazine.

 

[DiveNav]

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View attachment 194880

These graphs are how you compare the algorithms, .....

ediving.us ? View topic - Fine Tuning a Decompression Algorithm

good article there. .....

Thank you for using our slide and quoting our article.

We wrote that article few years ago when we decided to "fine tune" the decompression algorithm inside our eDiving and divePAL simulators.
Please note that this "fine tuning" is a relative concept as we wanted to position our algorithm "in the middle of the pack" when using a reference set of 4 dives (the ones used by Catalina Chamber). Those 4 reference dives are now available in divePAL for everyone to play with.

BTW, here below the result of our optimization effort

Alberto (aka eDiver)

 

[clownfishsydney]

My wife used to use a Tusa computer (which I think was really a rebadged Suunto) and I was using a Uwatec (various but all the same algorithm). On first dives, her computer was far more liberal than my computer. However, on second and subsequent dives, her computer was far more conservative. Therefore, it is hard to figure out how each computer will compare in real life to another.

 

[Hatul]

My wife used to use a Tusa computer (which I think was really a rebadged Suunto) and I was using a Uwatec (various but all the same algorithm). On first dives, her computer was far more liberal than my computer. However, on second and subsequent dives, her computer was far more conservative. Therefore, it is hard to figure out how each computer will compare in real life to another.

I find the same thing when I wear my Vyper and Galileo together. On first dive the Galileo is more conservative (shorter NDL) but on repetitive dives it flips around.

 

[Andyoak]

I wear my computers on different wrists and swim with one arm up and the other down, seems to keep the NDL about the same on both.

 

[victorzamora]

I wear my computers on different wrists and swim with one arm up and the other down, seems to keep the NDL about the same on both.

Smart! Way to trick those computers!!

I like to leave one with my O2 bottle at 20ft while I go on my dive. That way, no matter what my primary computer says.....my backup says my deco is clear so I'm safe and sound no matter what, because my computer says I can ascend...right?

 

[guyharrisonphoto]

One thing to mention is that one computer can be more liberal on a square profile, and penalize you hard (and unpredictably) for yo-yo or sawtooth profiles or short SIs. Even if ScubaLabs DID produce those pretty charts, it doesn't mean that's the case for all types of diving. The only way around it would be to put your "main" computer in "ultra conservative" mode to verify that you won't go into deco on your backup OR to be running identical algorithms. Otherwise, you need a bottom timer and some tables (or dive planner on your primary).

One more thing to mention: The most dangerous aspect of, and my biggest problem with, AI computers is that they tend to induce complacency. So, if you're trying to keep your AI computer connected just so you can have the "Air Time Remaining" or whatever they call it, be aware that that could get you killed. It's FAR too liberal for any real world scenarios as it doesn't even try to compute air-sharing or panic into its calculations.

PS- Mares is one of the companies that uses the goofy, proprietary, unpredictable algorithms that randomly punishes you for stuff you can't foresee.

I don't think AI has anything to do with complacency. You can also use the AI readout as merely a more convenient SPG, and then use the information as you wish. A DM telling everyone that the "plan" is "surface with 500psi" is just as complacent and potentially dangerous, using a regular SPG. At least with an AI algorithm, under that scenario, the computer will alert you when to begin your ascent, calculating your gas use during your own total ascent time including stops to reach the surface with the reserve.

If you are serious enough to plan a "rock bottom" gas plan for you and your buddy, you just monitor the pressure until it reaches your ascent number. On my computer, I have the option to program an alert for any PSI I want, which can alert me when we reach the ascent pressure. A nice back-up if you want it.

Like any tool, use it as you wish. I have seen no evidence or reports that AI has caused OOG situations, or otherwise harmed divers more than use of an SPG.