Question Shearwater Teric (GF40/85) goes into DECO on first dive (max depth 25.9m, avg depth 17.6, duration 48mins)

[Divedeeplastlong]

Possible, depending on how conservative the settings are.

40/85

 

[Divedeeplastlong]

Please post gf's.

40/85

 

[Divedeeplastlong]

Hi @Divedeeplastlong

I assume you were diving air, is that right? As above, having your GFs would help answer your question.

It looks like you went into deco at about 35 min. Your max depth was 85 ft, avg depth 58 ft. Based on NDLs on air, you could easily have gone in deco depending on your GF high and exact profile.

View attachment 862440

Why didn't you clear your deco?

Yes, I was diving on air, GF 40/85.

I didn’t clear my deco as my wife was feeling unwell (stomachache) nearing the end of the dive and she wanted to head up to the boat as soon as possible.

And since her AWU (GF 70/85), didn’t go into deco. I assume my teric had and issue so we proceed to ascent.

 

[Divedeeplastlong]

Exactly.

To the OP. From looking at the graphs, it appears your computer was working correctly. I don’t see any crazy depth changes to indicate a malfunction. NDL decreased during the dive until it reached 0. Then you continued on with your dive and after ascending for a bit descended to your deepest point on the dive. Did you check your computer during the dive? If so, did you understand what it was telling you?

To others, especially newer divers reading this thread. If your computer indicates a deco requirement, don’t just assume it’s malfunctioning and ascend without completing (gas permitting) the stop. If it’s not giving obviously false depth readings, it’s probably working as intended.

Hi, I was tending to my wife (new diver) so I didn’t really focus on my dive computer. As for the ascending and descending, we followed our dive guide.

Yes, thank you to all your replies. Looking back I should have followed what my computer was telling me instead of assuming it’s malfunctioning.

Moving forward, I will follow my computer’s instructions.

May I also ask, since I missed my deco stop for the first dive and dive 2 more dives (no deco) on the same day.

Is it safe for me to dive today? I’m feeling physically ok. No DCS symptoms.

 

[grantmac]

Follow your computer going forward, learn how to set GFs if you want to match with a buddy.
This is all rather personal but I'd dive tomorrow after those dives.

 

[rongoodman]

Changing the bottom number in your GF should have no effect on your NDL. That only affects how deep the initial stops are scheduled on a decompression dive.

 

[Sascha314]

Well a personal take, how I would carry on and interpret it. But I am not a professional, nor a medical doctor, neither did I analyze it fully. So its just an opinion, nothing to rely or reference on!

Usually with a healthy body, clean and slow ascent with doing a more or less safety stop there should be no issue even for the most possible aggressive setting. That is statistically speaking, if you do not or marginally violate the obligations. In the end all deco calculations are with lots of statistical and empirical data. Older computers have been much more aggressive... I set my computer a bit more conservative and follow it.
If you are more conservative on the settings and "violate" these obligations, you may have been very well within the limit of a more aggressive settings.
According to the Padi Table its 29min NDL at 25m. So depending on the profile its probably at the edge of a deco dive.
So from what I see you are most probably fine, especially, if you feel ok.
I would be more interested, why your wifes computer did not show a deco - or did it already clear on the ascend and you just did not notice? Maybe also because of the profile it was just on the verge and you have been a bit deeper as she was, and then because of the profile it did clear.

You could check your profile with subsurface and see if that corresponds, and also compare the profile of your wifea data, if you want to be sure. But I would say the computer was right.
.

However: Please follow the information on your computer, if possible. As far as I understood there was a dive guide who could perfectly well ascend with your wife and you could have stayed liked 2-3 more minutes down (well yeah ok you would have been alone ... trading risks..)

 

[Belzelbub]

Hi, I was tending to my wife (new diver) so I didn’t really focus on my dive computer. As for the ascending and descending, we followed our dive guide.

Understood on tending to your wife. The dive guide thing is an irritation of mine. Never JUST follow the dive guide. While they may be responsible for leading the dive, it's the individual diver who should be responsible. After all, the diver will have the consequences should something go wrong.

May I also ask, since I missed my deco stop for the first dive and dive 2 more dives (no deco) on the same day.

Is it safe for me to dive today? I’m feeling physically ok. No DCS symptoms.

Unlike your Suunto, the Shearwater won't lock you out. That means, that it will continue to track nitrogen loading on future dives based on your past dives. I'm not a Dr. so I'm not going to make any suggestions regarding the safety of the dive. No symptoms definitely is in favor of you being fine.

If you do decide to dive, then your Teric will continue to provide advice. As long as you follow it, and pay attention to how you are feeling you should be fine.

One additional information point. Look at the tissue loading graph on the Teric. It shows what it expects the various tissue compartments saturation to be currently. If the slower tissues are highly saturated, this might be more of a concern. Also, use the planning function to make sure the upcoming planned dives are doable.

 

[Sascha314]

Actually just a second thought for discussion, as I do not know how the computer exactly behave.

It seems like it was just hitting deconwith gf85. Slow descenty then a bit ascending and down again. Even with the rectangular profile it is close.
Now what actually was the deco stop depth with GF40, and what would it likely be with GF70?
Some start at 3m, and it is a high GF. Maybe the computer does not show it because the safety stop, which is supposed to be deeper, would clear it?

 

[scubadada]

Yes, I was diving on air, GF 40/85.

I didn’t clear my deco as my wife was feeling unwell (stomachache) nearing the end of the dive and she wanted to head up to the boat as soon as possible.

And since her AWU (GF 70/85), didn’t go into deco. I assume my teric had and issue so we proceed to ascent.

Your Teric and your wife's Apple Watch are running the same GF high 85, generally considered moderate in the spectrum from conservative to liberal. The NDL is entirely controlled by the GF high. I would expect the two computers to behave identically, or nearly so. I would imagine that your wife stayed enough above you on the dive that she avoided entering deco.

Do you recall how much deco time you had and what it was when you surfaced? If not, you can find that and other interesting information from the Shearwater Cloud log. In addition to your deco data, you might want to check your end surface GF. As you surfaced in deco, I would imagine that your surfacing GF was a little in excess of 85

Best of luck in your future diving