Aeris computer deco violations

[boat sju]

Using the simulation mode with air on my Aeris Elite (similar algorithm as your XR-1) it took 1hr 55m at 130ft before it requested a stop at 60ft. I think many recreational dive computers try to get you shallow for your deco stops assuming that that they were unplanned and you probably don't have enough gas to complete a deep deco schedule.

As a contrast, running an air dive on Vplanner (deco software) with VPM-B algorithm shows stops starting at 60ft after 20 minutes at 130ft.

Somewhere in my reading I did get the impression that the goal of the XR-1 (and I assume the rest of the Aeris line) is to get you out of the water as soon as possible once you get into deco mode.

ian: Were you suggesting staying out of the yellow even when doing rec NDL diving or just if you accidently go into deco?

 

[RedCash02]

I'm pretty sure here meant just doing recreational dives, because many people agree that the Aeris computers are pretty liberal with their NDL. I have an atmos2 and I let it go 1 into the yellow, but have the alarm set to go off if it hits the 2nd yellow bar. However, I'm in decent shape and in my 20's.

 

[boat sju]

Yeah, I got looking at the dive planner mode vs. my PADI tables and even there you can see the computer isn't real conservative. But then again my new tables show 10 min less NDL time at 70' than my old tables from when I was certified in '82. When I was in my 20's and in good shape.

 

[ianr33]

ian: Were you suggesting staying out of the yellow even when doing rec NDL diving or just if you accidently go into deco?

If it goes into the yellow during a dive thats fine,but hang out at safety stop depth long enough for it to go into the green before you surface.Think of it as a "mandatory safety stop"

I had a PM conversation with a scubaboard member sometime ago who had done a 2 tank dive with an aeris computer,come up from both dives with it in the yellow and ended up getting bent.IMHO if you make a habit of surfacing with them in the yellow,especially if you may not be doing perfect profiles and ascent, rates you are pushing your luck.

My Aeris computer gives me 19 minutes at 100 feet as the NDL. You could then make a rapid ascent to the surface and the computer would not complain.
By comparison V-Planner (deco software) on medium conservatism is asking for about 10 minutes of mandatory deco stops.

Dont let any of the above worry you,I think Aeris computers are great,just be aware that when Aeris calls the yellow area the "caution zone" they are not kidding.

 

[nineeightysix]

I have an Atmos AI and am interested in this thread. The manual says (to my read) that the yellow zone is not deco, but of course you need to account for personal differences. I would like to understand if in fact the Aeris algorithms are "old" and what the thoughts are around newer algorithms, deep stops and going into the "yellow zone"

One of the things I love about my AI is that it always shows me the most important dive time remaining whether it be air or NDL and that it adjusts that for (at least) whatever surface pressure alarm I set (for example to surface with 500 psi). Since I also have a nitrogen loading alarm set (for 1 bar into the yellow), will it consider that in the DTR shown?

I'm sending this link to Doug Krause for Aeris/Oceanic in the hopes he might comment.


Cheers

 

[boat sju]

ian,

It does all make me worry a bit since my tables show 20 min at 100' as NDL. You doing 10 minutes of deco as I cruise on past you would make me a little nervous when I ask you about it on the boat ride back to shore.

In reality I was taught way back when to take at least five minutes off the NDL, and we used bottom timer time (12 ft on/6 ft off depth) for repetative dive time calcs. I still do that with the newer more conservative tables.

I will stay out of (or remove myself from) the yellow. Thanks.

 

[miesemer]

Comparing the Aeris (elite) algorithm to the RDP on square profile air dives.

Here's a table I created, by running the simulator on my Aeris Elite, that shows the minutes to reach each yellow segment. The numbers in parentheses are the time as a percentage of the time to hit deco on the Aeris algorithm.



I agree that each person should have their own level of conservatism they apply to their diving based on their own physiological factors. For me, being in the yellow during a recreational dive is quite typical. However, I do strive to spend enough time at shallower depths to exit the water in the green.

 

[RedCash02]

Regardless of what my Aeris tells me, I always do a deeper stop for a couple minutes before I head up to do my safety stop if I'm diving around 100ft. I got in this habit after my AOW instructor told me it's always better to do an additional stop because you should never allow yourself to be low on gas and there's nothing to see back on the boat.

 

[boat sju]

Jeff,

Thanks. That's interesting. I think my XR only has one yellow segment. I assume it coincides with your first yellow. Maybe 986 will get a response from Mr. Krause and he can explain how those two computers differ in that respect. For me personally, staying out of the yellow shouldn't be a problem for the way I currently dive.

 

[boat sju]

Red - by the way - good luck tomorrow