Decompression Stop Guidelines - What we have to do if got deco alert?

[tursiops]

Dive theory should not be a "magical black box" with arbitrary inputs and outputs to dive professionals.

?? What is driving this statement? Did someone say this?

 

[formernuke]

I have issues with a lot of what you wrote.

• It's not an "emergency deco stop". It's just a mandatory deco stop.
  • Just say "NO!" to needless drama!
• If you're diving with a PDC, then please, please follow it.
  • Your 8 or 15 minute random stop may not fulfill your deco obligation.
  • Evaluate your gas supply as you decompress. Drowning will ruin an already bad day.
• If your deco was unplanned, sit out for the rest of the day.
  • There's just no excuse for accidental Deco
  • Take the time to evaluate your diving habits.
• If you missed any deco time:
  • Go on oxygen for a minimum of 20 minutes or 5 times the amount of deco time you missed, whichever is greater.
  • Monitor yourself for signs of DCS.
  • Stay out of the water for at least 24 hours or whatever your doctor suggests.

I think your thinking because your trained in deco.

You brought up a big problem with recreational training 5 years ago with this. All the way through DM that is what is still taught without regard for computers. Problem is as you stated your "unplanned deco" could be more than just thar 8 minutes at 15 feet. Heck my first deco dive was shallow for deco and we had stops at 50, 40, 30 and 20 totaling more than 8 minutes and the 20 was on 100 percent O2.

One of the many things where recreational training falls far short.




Good job on the new poster bringing back such an old thread.

 

[inquis]

If "decompression" is not "off-gassing" what is it?

I must not be making myself clear. Yes, of course, one definition of "decompression" is off-gassing. No question about it. That's just not the definition that comes to mind of the boat captain and tons of other divers the world round. For better or worse, a "deco dive" across the globe means one in which the "no decompression limit" [sic] or NDL has been exceeded.

You know this, which is why you won't tell the captain you completed your "decompression". You attempt to side step it by saying you didn't exceed "NDL", which while obviously differing from your definition of decompression, matches that of the captain. And yet you won't use his definition for the spelled out word "decompression"? C'mon, either be a pendant or not.

 

[L13]

?? What is driving this statement? Did someone say this?

Not in so many words, and certainly not you.

But: dive computer said you should stop a little longer at 3m ==> 48 Hour penalty was implied by the dive professionals in the original post.

 

[L13]

You know this, which is why you won't tell the captain ...

Either the captain understands deco and is just using the word as a shorthand (in which case he won't do anything stupid like 48 hour lockouts) or he doesn't and he isn't.

My original argument was not in how you talk about it with the captain, it was about how you understand the dive science of the situation and why a 48 hour lock out was stupid.

Yes, NDL does draw a sharp line in a grey scale region. Yes, we conventionally name these two regions. Yes, that naming scheme is usually useful. But: A 48 hour lockout demonstrates a fundamental lack of understanding of the nature of that line and that region, that being that it is a continuum of varying risk and the line is not drawn at a peak or a valley.

My point is that two points on either side of but close to that line are essentially the same from a dive science perspective, regardless of the different conventional names attached.

 

[AJ]

If it was locked out due to missed stops. Then the dive centre took the correct action. Although you could argue they only needed a 24hour off-casing period, then to rent another computer.

What I meant was: it seems the dive center relies on a computer to take the right action. They should have a protocol in place in case this happens, regardless of what computer is used. They should never rely on a computer to take the right action.

Neither should a diver, no matter what computer is used.

 

[L13]

I just realized this is a re-animation of a re-animation of a zombie thread about a second hand story about a 48 hour lockout. Here is a scenario where it all makes sense with a competent captain/crew:

crew: "why did you stay so long on your stop?"

diver: "My computer told me too."

crew: "You had deco?" (Thinking: Their flight out tomorrow afternoon is > 18 hours after next dive but that's not enough if they had deco).

diver: "My computer is a Suunto, it sometimes does non-standard things with stop times."

crew: (Thinking: Suunto! I've heard that it locks out for 48 hours if there is deco. I can use that to find out if it was deco or just a weird stop calculation). "Can I see your computer to see if it is in no fly or 48 hour lockout."

diver: "48 hours lockout for this is stupid. I'm not giving you my computer." (or grabs it back if crew already looking).

Captain: "Sorry you can't go on the next dive".

 

[inquis]

A 48 hour lockout demonstrates a fundamental lack of understanding of the nature of that line and that region

Maybe. It could also be they're pissed you couldn't follow one simple instruction and may be worried about what other instructions you'll ignore. Maybe something else, who knows.

Do I think 48 hrs is draconian? Yep. Would I look for a different boat next time? Yep.

 

[tursiops]

Maybe. It could also be they're pissed you couldn't follow one simple instruction and may be worried about what other instructions you'll ignore. Maybe something else, who knows.

Do I think 48 hrs is draconian? Yep. Would I look for a different boat next time? Yep.

If you don't like 48h lockouts then throw your Suunto away.

 

[scubadada]

So, the first 16 pages of this thread are from more than 5 years ago. It was briefly resurrected a year ago.

It was re-resurrected yesterday with a simple question about how a diver was treated by a dive operation after her computer went into deco, potentially being prohibited from diving. After considerable discussion, it turns out that she cleared the decompression obligation and was, ultimately, allowed to continue to dive, as generally should have been the case. If the operation had a policy of not allowing divers to go into deco, they might have had grounds to follow their policy. If she would not have fulfilled her deco obligation, her brand of computer would have locked her out for 48 hours. In 25 years of contemporary diving, 20 with a computer, I have never been asked by anyone to see my dive computer.

Most of the rest of posts have concerned "decompression" I am a simpleton with 2256 dives since 1997, about 5% light deco. If my computer does not exceed NDL and go into deco, it is a no stop dive and I can make a normal ascent, directly to the surface. If my computer goes into deco, it is a deco dive and I have an obligatory stop. If the obligation is very short and clears on ascent, I still had a ceiling, no different than if the stop was several minutes.

There are many brands of dive computers and many deco algorithms. Some of these algorithms are more conservative, and some are more liberal. I feel you are obliged to follow the algorithm of the computer you chose to use. I dive with 2 computers, an Oceanic running DSAT and a Shearwater running Buhlmann at a GF high of 95. They are reasonably matched, but not perfectly. If neither of my computers go into deco, it is a no stop dive. If one or both of my computers go into deco, it is a deco dive and I clear the obligation on one or both.

Of course, there is much more, like using SurfGF to choose your specific surfacing GF from an aggressive no stop or a deco dive. How long are SIs? @Gareth J has more than 2 hours in the UK, I have 45 +/- 15 min in SE Florida, they both work for our diving We'll leave those for another thread