Accidental DECO and mild panic in a non tech certified diver.

[Rechno]

I just don’t personally like this method. I want actual real DATA available to me. If I feel the need to add conservatism to my dive plan, then extending a safety stop is easy to do. In an emergency, I want to know my real MOD and safe TTS. And not have to try to play tricks, sort of like setting your alarm clock 15m early so you have time to hit snooze a couple times. ...no thanks!

I almost completely agree with you., however, if I would dive with a buddy on air, while I had Nx (rec diving, no deco planned) I would switch the computer to air, so that I would be closer to him concerning NDL (The issue about different computers/ deco models has been mentioned, so I usually try to synchronize it as best as I can).
The reason for me is, that I think it is easier to keep in mind the different MOD and stick to the Nx MOD, then it is to guess/ estimate, where my buddy would be concerning NDL. Especially if the dive is a multi-level dive. So the main reason would not be added conservatism/ safety margin, but rather to have a "harmonized" remaining bottom time.
Of course, if you have a buddy that is thinking while you are diving and the communication is, as it should be, this wont be necessary.

 

[Manatee Diver]

What??? Please elaborate and explain where my computer went into DECO. I'm asking this because I was never even close to my limits unless I'm missing something that shows in the dive profile that you're referring to.

I might be reading your software's profile wrong, but up top there is an upside down green plateau looking thing. In my software I only see something like that when I have a deco ceiling.

 

[Storker]

I would dive with a buddy on air, while I had Nx (rec diving, no deco planned) I would switch the computer to air, so that I would be closer to him concerning NDL

I prefer to assume that my buddy is able to read their computer for comprehension.

In any case, I've standardized on 32%, and in the deep-ish part of the rec diving depth range that means roughly a 50% increase in NDL compared to 21%. So it isn't that difficult to keep track of my buddy (run time plus remaining NDL time minus 33% minus run time = my buddy's remaining NDL time). Besides, I download my dives and prefer that my log reflects the gas I was actually using (OCD? Never heard of it...).

Notwithstanding the fact that I like to agree on a simple dive plan (max depth, max run time, NDL at relevant depths (-ish), min gas, rough directions) even though I dive strictly no-stop. And if we don't just plan our dive, but also dive our plan, we ought to be good. There may, of course, be some issues with the fact that our max depth/max runtime plan usually more or less assumes a multilevel/triangular profile. Typical plan: Max depth 30m, max runtime ... uh, let's see, 50 minutes? No, better make that 60 minutes to be certain. Yeah, that's good. "Hey, dive leader? Max depth is 30m, and max run time is 60 minutes! No, we won't go into deco!"

 

[Gareth J]

I prefer to assume that my buddy is able to read their computer for comprehension.

In any case, I've standardized on 32%, and in the deep-ish part of the rec diving depth range that means roughly a 50% increase in NDL compared to 21%. So it isn't that difficult to keep track of my buddy (run time plus remaining NDL time minus 33% minus run time = my buddy's remaining NDL time). Besides, I download my dives and prefer that my log reflects the gas I was actually using (OCD? Never heard of it...).

I use a second computer to track my buddy's NDL. The CCR has an inbuilt system, and when I'm on OC I put one of the redundant Suunto's on.

Notwithstanding the fact that I like to agree on a simple dive plan (max depth, max run time, NDL at relevant depths (-ish), min gas, rough directions) even though I dive strictly no-stop. And if we don't just plan our dive, but also dive our plan, we ought to be good. There may, of course, be some issues with the fact that our max depth/max runtime plan usually more or less assumes a multilevel/triangular profile. Typical plan: Max depth 30m, max runtime ... uh, let's see, 50 minutes? No, better make that 60 minutes to be certain. Yeah, that's good. "Hey, dive leader? Max depth is 30m, and max run time is 60 minutes! No, we won't go into deco!"

Storker, diving with a club I assume you plan and log your dives properly. When diving with my club, you log your planned schedule before you get in the water. Even when I was doing deeper stuff on runtime with a couple of private groups, we always had to write the runtime down on the log before we kitted up. - there was an upside, the tea was already brewed when you got back on board
Also, when thinking about it, most of the UK boats like to know the max dive times before they put you in. Overstaying is very bad form, that's when they start thinking about putting the first call in to the coastguard. At least if they see a DSMB they know you are on your way up.

 

[Storker]

Storker, diving with a club I assume you plan and log your dives properly. When diving with my club, you log your planned schedule before you get in the water. Even when I was doing deeper stuff on runtime with a couple of private groups, we always had to write the runtime down on the log before we kitted up. - there was an upside, the tea was already brewed when you got back on board
Also, when thinking about it, most of the UK boats like to know the max dive times before they put you in. Overstaying is very bad form, that's when they start thinking about putting the first call in to the coastguard. At least if they see a DSMB they know you are on your way up.

We align pretty well on this.

The issue is, of course, what kind of dive profile I expect to dive. Generally, I won't have any problems diving to a max depth of 30m and have a run time close to an hour. Our dives are almost never square profile. Even if the NDL on air (and, incidentally, roughly my min gas time) at 30m is 20 minutes. As I nearly always dive a multilevel/triangular profile, I have to take that into account when I give my plan to the DL. Because I don't want to put them in the bind to decide whether or not to call emergency services.

Worst case, I'll have to wait some 15 or so minutes for my tea and cookies/biscuits

 

[leadduck]

I wish more people would take Tec 40, Extended Range, AN/PP etc. I also wish the agencies would change they way they're marketed moving the basic Deco course away from the mysterious (to most) "Tec" and back to the mainstream.

I'd wish so too, but the problem of the OP's sister is different: she didn't even follow PADI OWD training for the case that you accidentally exceed NDL time (= know your computer, abort dive, don't panic, follow your computer). OWD stuff has to work first before going into planned deco diving.

 

[Charred]

I'd wish so too, but the problem of the OP's sister is different: she didn't even follow PADI OWD training for the case that you accidentally exceed NDL time (= know your computer, abort dive, don't panic, follow your computer). OWD stuff has to work first before going into planned deco diving.

I do wish that OW or AOW included more on what to do if you slightly exceed NDLs. Many will say follow your computer but if you have no idea what your computer will do or show, then what? There is a chicken and egg here, if you have never been in deco, you have no idea what the computer will show or do. How do you learn this?

Personally I think this needs to be taught. However, I understand agencies are not teaching this because they are afraid people will then start doing deco on rec dives.

Not sure I would agree one needs to take a tech class to learn this. I would argue it should be part of any Deep cert that is done as part of AOW.

Interesting thought: what happens more often: rec diver goes OOA or rec diver exceeds NDL? Given the number of locked computers I've seen, my experience points to the latter YET rec divers are given no training for the latter and extensive for the former.

 

[Manatee Diver]

I do wish that OW or AOW included more on what to do if you slightly exceed NDLs. Many will say follow your computer but if you have no idea what your computer will do or show, then what? There is a chicken and egg here, if you have never been in deco, you have no idea what the computer will show or do. How do you learn this?

Someone on here posted "If your dive computer is showing a screen that you've never seen before you are probably in deco." But that can be solved by RTFM.

 

[Storker]

I do wish that OW or AOW included more on what to do if you slightly exceed NDLs.

From what I remember from my OW and AOW, if the student were able to remember what they're taught, they should know enough if they accidentally overstayed their NDL slightly.

That requires, of course, that the student is able to remember what they're taught. And I wouldn't be willing to bet my savings on that.

 

[caruso]

I might be reading your software's profile wrong, but up top there is an upside down green plateau looking thing. In my software I only see something like that when I have a deco ceiling.

That green shaded area in the dive profile might be a "close to DECO" indicator but someone with more knowledge of subsurface software would need to weigh in on this one.

Edited to add:

The green appears and goes away if I toggle "calculated ceiling" which would support what you said about me potentially being in DECO but again it never happened during the dive. Go figure.