Missed deco stop on Perdix. Need help understanding dive log

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In the OP's defense, there are places where current and wave surge make a 10' stop really uncomfortable. Add a plunging dive boat who left you only an anchor line instead of a down line to decompress on, and you can be bobbing several feet without a jon line to buffer your deco line movement.
Now add the buoyancy changes in suit volume that close to the surface and you can understand why he made that statement.
 
In the OP's defense, there are places where current and wave surge make a 10' stop really uncomfortable. Add a plunging dive boat who left you only an anchor line instead of a down line to decompress on, and you can be bobbing several feet without a jon line to buffer your deco line movement.
Now add the buoyancy changes in suit volume that close to the surface and you can understand why he made that statement.

Totally agreed on that. My local conditions can be like that. Still doesn’t explain why he had so much deco and didn’t understand what his Perdix shows.
 
Flexible Control of Decompression Stress - Shearwater Research

So, it looks like you went into deco at about 30 minutes, but did not start your ascent until about 13 min later. Was that the dive plan? How much deco did you have at the maximum? Did you take a look at your SurfGF to see what your GF would have been with a direct ascent to the surface? You then did a slow 8-9 min ascent and nearly got down to your GF high.

I am in agreement with the others who recommended you obtain the knowledge and training to execute dives safely.
 
My Perdix is in high conservatism mode, GF 35/75. I did not complete my deco stop at 10 feet. This was the first time I went past NDL.

Below is my my dive profile. I don't understand the deco and GF data.
  1. Does the height of the red deco information correspond to the deco stop depth of 10 feet?
  2. My ending GF was 77%. What exactly does this mean?
  3. 10 foot deco stops are hard to hold in a drysuit. If I want a deeper stop, like 15-20 feet, should I switch the GF away from 35/75?
  4. How close to being in trouble was I?
I felt completely fine after the dive. Gas was EAN 32.

HI MolaSquared,

@rsingler answered you questions best above. If your dive count in your profile is accurate, you're still a reasonably new diver, and not having had any advanced training (and by advanced, I mean deco, not AOW), you don't know what you don't know. The other posters on this thread are not wrong, but they are also being a bit harsh.

They are not wrong - that is not a great dive profile. But instead of listening to them chastise you , it would be worth asking yourself, and more importantly answering honestly, some questions about this dive.

It is easy for newer divers, especially those used to relatively shallow diving, to forget about NDLs because they hardly ever hit them. This leads to poor (or no) planning. The question to ask yourself - did you plan this dive? At this depth? For this period of time? If so, did you follow the plan?

If you've never been into deco before, you may not have realised that your computer was telling you. Spend some time topside with your computer, and make sure you know how to understand what its telling you. And when you're on a dive, make sure to keep an eye on it, and heed what it's telling you. Unless you have planned to do staged deco (which you are not trained for, so you shouldn't be doing it), when your NDL is approaching 0, make sure you start your ascent.

All dives should include a safety stop. You did not perform one at all. Why not? Did you plan to? Did you forget? Were you not able to hold depth at 15' or 10'? Were you low on gas? Was there another emergency?

You need not respond to my post, but it would benefit you greatly if you could answer those questions honestly to yourself.
 
@rsingler addressed all your points.

Please don’t go into deco without planning and training.

But, to reiterate a point that others made here, if you happen to go past your NDL (hopefully that won’t happen without planning), remember that the ceiling is a ceiling: it is like an invisible ceiling you should not breach.

You don’t have to be at 10’ exactly if you know that you won’t be able to hold a stop at this depth: it is saying you shouldn’t go above 10. If you were staying around 15’ you would most likely decompress although at a slower rate.

The perdix manual explains what it will displays if you accidentally go past your NDL, page 15 and 25 in the link below. You should get familiar with these sections in case you accidentally go past the NDL.

https://www.shearwater.com/wp-content/uploads/2015/12/Perdix_Manual_RevA.pdf
 
Totally agreed on that. My local conditions can be like that. Still doesn’t explain why he had so much deco and didn’t understand what his Perdix shows.

Also where was the dive buddy? Did the dive buddy also go into Deco and not realize or did they just ignore NDL?
 
Still doesn’t explain why he had so much deco and didn’t understand what his Perdix shows.

People who have not been explicitly shown what it is like when they are in deco will often have no idea what is going on. Even then, if it is not habit they will make mistakes. A video of the whole cycle of a deco dive would be a help but watching such a thing seems like planning and the lack of planning is the real issue.

The UX on some of these devices is a bit lacking too. For example, a buddy (who has only a handful of deco dives) recently left me at 6m and carried on to 3m expecting the computer to start counting down the stop by the second as that is how the safety stop works. You could say “what an idiot” or “ah, that is a fair point, are they really different? Is it necessary that they are different?”
 
My Perdix is in high conservatism mode, GF 35/75. I did not complete my deco stop at 10 feet. This was the first time I went past NDL.

Below is my my dive profile. I don't understand the deco and GF data.
  1. Does the height of the red deco information correspond to the deco stop depth of 10 feet?
  2. My ending GF was 77%. What exactly does this mean?
  3. 10 foot deco stops are hard to hold in a drysuit. If I want a deeper stop, like 15-20 feet, should I switch the GF away from 35/75?
  4. How close to being in trouble was I?
I felt completely fine after the dive. Gas was EAN 32.


View attachment 681640

The algorithm obsessed here are saying this was fine. I disagree and suggest you really try to have some kind of stop in 3 to 6m. The GF number is a single number for the worst compartment which hides the following compartments (assuming that compartments are a reasonable model at all) and so a wide range of risk can be represented by that same number.

Any stop is a lot better than no stop. Give perfusion a chance.
 
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https://www.shearwater.com/products/teric/

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