As a rec diver, what to do if I breach my computer's NDL???

[Lorenzoid]

There may not be data to differentiate risk levels posed by following different deco algorithms, but some of us may get peace of mind by following what's widely considered a "conservative" algorithm or plan. Perhaps it's a false sense of security, but it makes me feel better, more relaxed, and I suppose that has some value. My goal is to enjoy my diving, and I enjoy it less when I start wondering whether I might be pushing the envelope.

It's pretty clear Craig understands risk. Some of us have low risk tolerance, and others have high risk tolerance. I don't think many of us would go so far as to berate another diver who clearly understands the level of risk implicated by his diving practices. I think the concern that some of us have is not for people like Craig but for divers who don't fully appreciate the relationship between their diving practices and level of risk.

Anyway, I didn't mean to jump into a general discussion about risk tolerance or violating no-deco limits, as my post was directed solely to RickyB's anecdote.

 

[Agility]

but it's my understanding that sawtooth profiles somehow trigger the Suunto RGBM algorithm to add conservatism).

According to
Int J Biomed Comput. 26 (1990) 231-256
Elsevier Scientific Publishers Ireland Ltd.
by B.R.Wienke
you are right.

 

[boulderjohn]

When the international conference that examined reverse profiles (IIRC in 2001) determined there was no physiological reason to prohibit them, a notable exception to that decision was by Brice Weinke, author of the Suunto algorithm. On his insistence, the workshop left the recommendation in for decompression diving. based on that evidence, I am pretty sure a Suunto will also penalize you for a reverse profile.

 

[SmacA]

Many years ago, and when I was far less experienced, I unintentionally exceeded my NDL.

I had been diving 3-4 dives a day. On the 4th day I was paired up with yet another an instabuddy. We did dive one, and saw I was getting close on NDL time pretty quickly.

So I mentioned PRE-DIVE that I might need to shallow up early into the dive because of this, and I'd point at my watch to let him know. Long story short, during the dive I'm frantically pointing at my watch, and telling him I need to go up, and guess what.... Mr oblivious ignores me, if anything going deeper.

Faced at this point with a completely new display on my watch, I abandoned my buddy caught up with the dive guide, and showed him the watch. We agreed underwater I'd go up above the group, and swim in the depth range the watch was showing. As it was a wall drift with a boat pickup, and we were only 15 mins in, this made sense for them.

Needless to say my breathing rate went up, both the separation anxiety (I was now 10m+ above the main group on my own), and the mind wandering that I would get to the surface and become instantly bent. Fortunately being relatively shallow to the main group, I had stacks of air, but it certainly wasn't a great feeling. I really had to calm myself down.

So things I learned:
- RTFM so you understand the display on the watch
- Never rely on instabuddies
- Give yourself a couple of mins margin
- If you just creep over NDLs you won't instantly get bent.
(This is important, because a panic spiral caused by worrying about the what-ifs, is even more dangerous.)

Si

 

[victorzamora]

I never thought that "RTFM" was something I needed to do. I've done deco dives on my computer. I recently read the manual (looking for something else). I learned a LOT from it. It's a very underrated thing, and I'm not sure if it's been mentioned before you. Thanks for pointing that out

 

[Lorenzoid]

When the international conference that examined reverse profiles (IIRC in 2001) determined there was no physiological reason to prohibit them, a notable exception to that decision was by Brice Weinke, author of the Suunto algorithm. On his insistence, the workshop left the recommendation in for decompression diving. based on that evidence, I am pretty sure a Suunto will also penalize you for a reverse profile.

I never thought that "RTFM" was something I needed to do. I've done deco dives on my computer. I recently read the manual (looking for something else). I learned a LOT from it. It's a very underrated thing, and I'm not sure if it's been mentioned before you. Thanks for pointing that out

In fact I gleaned this tidbit about the Suunto RGBM algorithm adding conservativeness for reverse profiles from section 9.2 of my Suunto D6 manual, which pretty much states just that. Yes, it pays to RTFM to get the most out of your computer.

 

[Tigerman]

I never thought that "RTFM" was something I needed to do. I've done deco dives on my computer. I recently read the manual (looking for something else). I learned a LOT from it. It's a very underrated thing, and I'm not sure if it's been mentioned before you. Thanks for pointing that out

But its such an un-manly thing to do.. The manual is supposed to go in the trash with the wrapping!

 

[faze]

It has probably already been mentioned by the book Deco for Divers is simply fantastic for anyone wanting to know more about Deco than most courses offer (recreational courses) without getting into scientific papers.

My advice would be learn what your computer is telling you and dive according to the information it offers. I had a diver back in autumn who was moaning about the fact that their brand new computer had malfunctioned at depth... reality was that they had entered deco and had no idea what the new display was telling them!

 

[scubadada]

There may not be data to differentiate risk levels posed by following different deco algorithms, but some of us may get peace of mind by following what's widely considered a "conservative" algorithm or plan. Perhaps it's a false sense of security, but it makes me feel better, more relaxed, and I suppose that has some value. My goal is to enjoy my diving, and I enjoy it less when I start wondering whether I might be pushing the envelope.

It's pretty clear Craig understands risk. Some of us have low risk tolerance, and others have high risk tolerance. I don't think many of us would go so far as to berate another diver who clearly understands the level of risk implicated by his diving practices. I think the concern that some of us have is not for people like Craig but for divers who don't fully appreciate the relationship between their diving practices and level of risk.

Anyway, I didn't mean to jump into a general discussion about risk tolerance or violating no-deco limits, as my post was directed solely to RickyB's anecdote.

Good for you, good for me