Rising GF99 after surfacing???

[rsingler]

Yes, first example was v93, which I believe is current version for Perdix AI. Second example was an older dive from a couple of years ago with a Petrel controller and an older firmware.

I have sent an email to Shearwater to ping the system with a link to this thread. They're very good about responding.

 

[harvalen]

Does the Shearwater end the dive when you actually get your arm above the surface or somewhere deeper than that? The subsurface logs I've seen from Shearwater computers seems to end the dive somewhere between 0.4m and 1.2m. One of them shows GF 51% and Surf GF 70 at 1.2m, just before dive ends.

So it could be that the lower number is at ~1m depth and the peak is when you get your arm out of the water the first time.

 

[rsingler]

One of them shows GF 51% and Surf GF 70 at 1.2m, just before dive ends.

That's just the sort of experiment I wanted to try next. Based upon my observation that GF99 declines about 2%/minute (+/- 2%), I wouldn't expect GF99 to drop more than 4% between 1.2m and the surface from offgassing, and wouldn't expect it to rise more than 6% between 1.2m and the surface from changing ambient pressure.

Therefore, maybe I should be reassured that SurGF is indeed predicting max GF99, and that max GF99 is the correct value, but appears 2 min late due to processing/graphing lag.

Although that means I can't trust the logged "end dive GF", at least the graph shows me my risk.

 

[BlueTrin]

If you email Shearwater they will usually reply within days.

Edit: saw you tagged them

 

[L13]

That's just the sort of experiment I wanted to try next. Based upon my observation that GF99 declines about 2%/minute (+/- 2%), I wouldn't expect GF99 to drop more than 4% between 1.2m and the surface from offgassing, and wouldn't expect it to rise more than 6% between 1.2m and the surface from changing ambient pressure.

Therefore, maybe I should be reassured that SurGF is indeed predicting max GF99, and that max GF99 is the correct value, but appears 2 min late due to processing/graphing lag.

Although that means I can't trust the logged "end dive GF", at least the graph shows me my risk.

It looks like the end of dive GF is logged just a little early, compared to actual surfacing max GF=GF99 at the actual surface.

 

[rsingler]

Well, good news and worrisome news...

I heard back from Shearwater and they asked about my firmware, serial number, and Shearwater version.
Not wanting to be dismissed as just out of date, I updated my desktop Shearwater Cloud from v.2.9.6 to v. 2.10.0. That may have been a bad idea. Until we hear more info from @Shearwater , I think you should keep your old Shearwater Cloud software.

Why do I say that? Because the new version truncates my dive graph immediately upon reaching 0.0 feet! I instruct my dive computer to not end dive for 120 seconds after the dive. The previous Shearwater Cloud software continued my graph until my designated dive end. The new version stops my dive, and the concerning increase in GF99 graphed for the two minutes following surfacing has disappeared! I don't know where the truth lies.

Below are pics of the old graphs and the new graph showing differing end dive GF99. With this example of a 13% discrepancy, I think this issue needs to stay open, and I'm distressed at no longer being able to see what my computer was calculating for the next few minutes.

Shearwater Cloud v.2.9.6 Android:

Shearwater Cloud Desktop v.2.10.0

Note that the additional data has disappeared!
The good news is that the end dive GF99 is now 53%. That's still not as high as the max GF99 (56%) that I saw graphed before I updated my Cloud software, but it's better than the 42% when I hit the surface.

Unfortunately, that still doesn't explain why 28% is tabulated as my end dive GF99 on the data page. But maybe I can write that off to old Petrel firmware.

Hang on to your current Cloud software until all these discrepancies get explained! Or upload the new version on a different device and see if your graphs have been truncated too!

 

[-JD-]

@rsingler any chance that there is a option/setting that was added in the new version that determines the end of graphing time and the defaut is 0s after surface?

 

[rsingler]

I'll look

 

[BlueTrin]

I'll look

Maybe they thought it’s easier to just cut the graph to fix the issue

No surfacing = no GF going up after surfacing

…

Problem solved!

 

[rsingler]

That possibility crossed my mind, but I really don't think Shearwater would do something like that. The fact that the newest software version is showing a closer correlation to max GF99 makes me think they were already on it. But the inability to track GF99 until  I say that the dive is over just makes more work for me, now that I'm alerted to this issue.
I'll simply watch GF99 for three minutes after my next deep dive and see if it increases briefly, whether my graph is cut off or not. If so, I can raise the issue again, if it's more than a percent or two. But I think the newest software is a 95% solution.

In the meantime, I need some group assistance:
All the lurkers who are reading this thread without commenting, and are diving Shearwater now?
Help us all out and track your GF99 (five right button pushes) for three minutes after your dive, okay? Write it down, and when you get around to uploading your dive to Shearwater Cloud, compare what you wrote down with what SW graphed at the end, if (like me) you can't see past when you reached 0.0ft, no matter what you told your computer was "dive end time." If there's a significant discrepancy, we can talk about it.
If I can't go diving again soon, I'll dive my toy in the pressure pot, and we'll look at it that way.

Meanwhile, I've had four follow-up emails from the SW software team, so we have their attention. Kudos to @Shearwater, as usual!!