DumpsterDiver emergency ascent from 180'

[dberry]

Does anyone know if DD's original plan included any deco, or was planned entirely as a bounce? (Sorry, I'm sure this came up earlier, but the thread is >100 posts now and I'm lazy.)

 

[CuzzA]

In the original thread, I said that when I do a recreational dive with a Shearwater computer, I don't bother to take it out of tech mode. When it is in tech mode with the GFs I use, it will go into deco a little before almost any recreational computer, and when it does, it is asking me to do one minute of deco. I thus don't care if I stray a couple minutes past the NDL, because I know it is within the NDLs of most computers, and it will usually clear before a 3-minute safety stop is over. If I were to put my computer into recreational mode, I could do the exactly the same dive with no NDL issue at all.

John, thank you for clarifying your post. (I edited your original post slightly to further the discussion within the TOS)

So let's lay out a scenario that would fit your guideline...

If you're at 100 ft. (rec. dive) with no redundancy and say 3 minutes of deco (light) following your computer (tech mode) and about to head up when suddenly the diaphragm blows out of your first stage and now you have to make a free ascent is there a lesser possibility of you coming up bent simply because if you were in rec mode you may have had just 3 minutes left of NDL time?

I would argue maybe, maybe not. It depends on a number of variables all they way down to how many ounces of water you drank before the dive.

What's the difference between cutting your NDL razor thin with no redundancy compared to cutting your redundant gas supply razor thin?

I think it's worth repeating... if anything is to be gained from this thread, it's you shouldn't flirt with decompression without redundancy and that redundancy should be enough to get you home safely and complete any stops.

 

[tomfcrist]

There are times though CuzzA when blowing off small amounts of deco is actually accepting less risk than staying in the water...

I.e.: when extremely cold, when gear is malfunctioning, badly motion sick...etc.

Most of those problems could be em edited with better planning or redundancy. However some are not. Like when a drysuit tears during an arctic dive...I'll tell you straight up, **** that last 5 minutes of deco....I'll suck O2 on the surface for a while.

 

[Steve_C]

You have to evaluate the options and go with the safest. It may or may not be doing 2 more minutes of deco or a doing a safety stop. 30 minutes of deco is "a real deco obligation". A couple of minutes of deco depends on your computer or your choice of algorithm.

 

[Storker]

I believe CMAS 3 star and BSAC advanced comes close on depth limits.

Depends on which Diving Federation you're gotten your CMAS 3* with.

More than once I've seen people believe that CMAS is the same type of agency as PADI or BSAC. It isn't. It's a group of national federations who have somewhat different certification standards and cert limits. A French CMAS 1* isn't the same as a Norwegian CMAS 1*.

What you can be sure of, is that any national CMAS cert as a minimum fulfills CMAS' requirements for standards and syllabus, but that's about it. The national federations are free to impose higher standards, more extensive syllabi or limit the diving that the certificate is good for. I was surprised to learn that a FFESSM 1* diver wouldn't be allowed to dive unless accompanied by a buddy with a higher certification, since we allow our 1* divers to do that. After all, the 1* cert fulfills the ISO 24801-2 Autonomous Diver Standard just like PADI OW does. OTOH, our 3* cert only certifies you to 40m. At least that's what it does today.

And when comes to BSAC, my impression is that they rely heavily on mentoring. I doubt that many BSAC dive officers would allow a freshly certified diver to plan a dive to 50m on a club dive, even if they were certified for that depth.

 

[w3dge]

What's the difference between cutting your NDL razor thin with no redundancy compared to cutting your redundant gas supply razor thin?

Getting bent for encroaching close to, or over, NDLs isn't a certainty. And even if bent, you can often be unbent.

Not being able to breathe underwater once you have run out of gas is a certainty. And once drowned, you can't be undrowned.

I'd say there's a significant difference.

 

[Colliam7]

Jyou shouldn't flirt with decompression without redundancy and that redundancy should be enough to get you home safely and complete any stops.

Formatting added for emphasis - Well said!

 

[Diver0001]

Getting bent for encroaching close to, or over, NDLs isn't a certainty. And even if bent, you can often be unbent.

Not being able to breathe underwater once you have run out of gas is a certainty. And once drowned, you can't be undrowned.

I'd say there's a significant difference.

It should be made clear to anyone who encroaches near or over the NDL's as you put it, that they should be doing so with a plan. Blowing off a few minutes of a stop because of running out of air or making a very fast ascent like the one in the video because of not having made an adequate contingency plan may not kill you (every time) but it is dangerous and it is avoidable.

DD keeps "getting away" with these things. He has had many such avoidable incidents in the past that are reminiscent of this and over time I have only seen evidence of his complacency deepening. For example, we still haven't discussed on this thread why the regulator failed in the first place. Was this also an effect of complacency? Poor maintenance? incomplete pre-dive checks, if they were even done? Perhaps even diving with a reg he knew wasn't entirely ok and thinking, "whatever" .... we don't know, of course, but complacency is more than just going to 55m depth without a plan-B. The root cause of this incident may have started on the boat or even weeks or months before this dive took place.

Let's be clear about something. Getting away with something is not the same as doing the right thing. Complacency among experienced divers is a serious risk factor. When I look at this video from the perspective of an instructor and a technical diver with 30+ years of experience I don't see "a good save"... I see a diver who gets in these kinds of predicaments on a fairly regular basis. I see a diver whose wife I pity for the stress she must feel when he goes diving (if she understands how he dives) or for the grief she will, at some point perhaps, feel when Murphy and Darwin get coordinated and have an "on day".

This thread and the video have great value to the community because it very clearly demonstrates something that we talk about a lot on this board, namelijk the deadly effects of complacency among experienced divers. What we are seeing here is almost the text book example of what we mean when we talk about that.

It is deeply disturbing to think that the diver was proud of getting away with it to the point of asking his friend to post it on scubaboard so we could all be impressed by his skill. To me that is proof positive that he has lost perspective on safety, perhaps completely. He IS the diver we mean when we say "complacency kills".

Now with that in mind go back and watch the video again from this perspective.

R..

 

[stuartv]

asking his friend to post it on scubaboard so we could all be impressed by his skill.

Where did you get that information? I thought the video was posted here without his knowledge.

 

[Diver0001]

That wasn't the impression I have. If I'm wrong, I'm wrong. It's an assumption/educated guess based on more than just this thread. Now let's move along.

R..