Garmin Descent x50i experience?

[Nick_Radov]

So I’m not sure how to download the dive, but the Garmin Dive app does show a little more data.

You can connect the device to a computer with a USB cable and copy the FIT file directly (just like a flash drive). Or if the activity has already synced to Garmin Connect then you can download the FIT file there. Post a copy here and we might be able to figure something out for you.

 

[yn37605]

Looking at my MK3i under Dive setup in the Garmin Dive app, the GF is shown next to each selection. If you select Custom, the default is 35/75.

 

[Flamebut57]

Attached is the file. I was not able to attach it directly so I renamed it as .zip (I did not actually zip it). You will need to rename back to .fit to use it.

 

[Nick_Radov]

Attached is the file. I was not able to attach it directly so I renamed it as .zip (I did not actually zip it). You will need to rename back to .fit to use it.

I uploaded your file into FIT File Viewer. It shows Low GF % = 97% and High GF % = 97%. Those are technically valid settings but quite odd and not something that most divers would intentionally pick as a custom conservatism setting. The really weird thing is that at the start of the dive you were already at 108% N2 loading, so you were past the NDL when you entered the water. At one point you had over an hour of deco, which obviously doesn't make sense.

You're probably dealing with some kind of device failure so you'll need to contact Garmin support. It's possible the device had some kind of pressure sensor or software failure and either it never cleared nitrogen loading from the previous dive, or kept accumulating during the surface interval due to thinking you were at a higher ambient pressure.

 

[Divin'Papaw]

Great investigation & analysis @Nick_Radov. Not only is GF 97/97 extremely unusual, but those settings would lead to opposite behavior than what was observed. The NDL allowed would be on the high end, not the reverse. Your assessment that it is some sort of hardware or software issue given the N2 loading at the start of the dive is highly likely. Definitely contact Garmin support @Flamebut57.

 

[Flamebut57]

either it never cleared nitrogen loading from the previous dive, or kept accumulating during the surface interval

Her previous dive log shows it ending much lower than 108% so my guess would be the latter.

Thank you for taking a look. Not only is it annoying that it didn’t show the values in the readily visible log but I don’t know what those values mean.

I am curious to look if 97 is the highest setting it will let you input.

Definitely contact Garmin support @Flamebut57.

I’ll definitely be reaching out to Garmin today or tomorrow.

 

[Nick_Radov]

I am curious to look if 97 is the highest setting it will let you input.

I doubt it. I don't have that model of computer but other Garmin computers allow for setting custom conservatism Low / High GF % anywhere from 1 – 100. So I think you could put both at 97% as a custom conservatism setting, but it would be kind of odd and doesn't match any of the preset values.

 

[inquis]

So this is what I see in the log on the Garmin Dive app.

The really weird thing is that at the start of the dive you were already at 108% N2 loading, so you were past the NDL when you entered the water.

I believe the "nitrogen loading" in the screenshot is quite different than the common GF99 metric and is defined relative to 0.79 atm:
Nitrogen Loading = PN2/0.79 - 1

For example, 0% equates to a partial pressure of 0.79 atm, which is much less than a surfGF of 0. A nitrogen loading of 108% would be a tissue tension of 1.64 atm. How this relates to GF99 is tough to say, because we don't know which tissue compartment was controlling. Assuming TC4 (18.5 min halftime), it would correspond to a GF99 of 64% (and lower/higher for faster/slower TCs).

 

[JrobC]

TLDR: I recommend turning off the touch screen

I just finished a dive trip in Belize and did have something happen with one of the computers.

My partner and I did a dive to 100ft. I went to 99 ft and my partner went to 105ft. Her computer said she busted her NDL and gave her an hour of deco. Some of our group was deeper than her so I was really scratching my head. I concluded at the time that it must be a minute of deco and we would just make sure to do that.

We continued the dive and at the end ascended to 10 ft where we realized it had said 57 minutes of deco. I signaled the dive master and was basically ignored (which was an issue I don’t want to get into here). We did a long safety stop for 10-15 minutes at 10 ft and then I signaled that I would surface.

I surfaced and explained the situation and was told that her computer must be malfunctioning and to tell her to ascend.

As a newer diver with no notion as to how long a deco stop should be or anything this was pretty scary but we really didn’t have any options at the time.

She surfaced and all was ok but it was very uncomfortable. It definitely put a damper on the dive trip and was the straw that broke the camel’s back for my partner.

Afterwards I reviewed our dive computers. Our nitrogen loading on all previous dives seemed to match pretty closely (within 10 percent). Her depth and time seemed accurate (100-105 ft for 90 seconds). The only thing that stood out to me was that her conservatism after her computer locked her out was set to custom.

My best guess as to what happened was that at the surface the touch screen went on the fritz and changed her conservatism settings. After this I have turned off the touch screen on both of our computers.

I plan on doing a longer review of my experience but I too have turned the touch screen off. I really like the computer but some times when swimming out the water or something must activate the screen because it starts jumping thru screens like I’m hitting buttons.

 

[KerrenL]

How was it for aidemount? Does it have a specific sidemount mode like the Pernix? Does it calculated combined GTR for the two tanks