Diver Dies in Lake Huron on the Dunderberg

[limeyx]

then point out what is wrong with my argument, I am with yours.

Right is just that, right, and NOT because I'm saying it!

You haven't shown any evidence to support your case (admittedly neither have I)
You haven't given any examples of anyone that was saved after being sent to the surface by inflating their BC (although I actually did present one similar case)

You also haven't presented any evidence that helium is going to give significantly more severe DCS when doing an ascent that is shall we say faster than your deco table might say but maybe not as fast as a buoyant ascent.

You basically said Shooting the guy to the surface is RIGHT because they only have 4-8 minutes, and its RIGHT

leave the guy in the cave if you cant get them out in 5-8 mins because its RIGHT

You said Helium is going to give you much worse DCS on a more rapid ascent because I am RIGHT

 

[Randy43068]

hate to say it Nick, but you're nuts

 

[cerich]

You haven't shown any evidence to support your case (admittedly neither have I)
You haven't given any examples of anyone that was saved after being sent to the surface by inflating their BC (although I actually did present one similar case)

You also haven't presented any evidence that helium is going to give significantly more severe DCS when doing an ascent that is shall we say faster than your deco table might say but maybe not as fast as a buoyant ascent.

You basically said "Shooting the guy to the surface is RIGHT because they only have 4-8 minutes, and its RIGHT"

You said "leave the guy in the cave if you cant get them out in 5-8 mins because its RIGHT"

You said "Helium is going to give you much worse DCS on a more rapid ascent because I am RIGHT"

Nick,

Seriously, you obviously have not comprehended my posts. I have given the reasoning behind my recommendations.

I am honestly shocked by the reaction I have garnered from your team, truly.

You use quotation marks above that you are ascribing to me that actually are not what I said....

As far as easier to get bent on Helium on a rapid assent than on air or Nitrox, well if you don't get that...you don't get that. Helium is a much smaller molecule, it gets in places quicker and out quicker. If forced to expand rapidly (like in a rapid assent)when in a place it got to quicker than the other gases discussed then it is more likely to cause damage. Your argument in relation to helium solubility compared nitrogen ( lipids solubility actually) has some grounding but isn't applicable, and as such when you base an argument on a incorrect assumption, the entire argument is false. Helium will really mess you up on quick assents, much more so than air and/or nitrox.

Anyway...it is what it is.

 

[limeyx]

Nick,

Seriously, you obviously have not comprehended my posts. I have given the reasoning behind my recommendations.

I am honestly shocked by the reaction I have garnered from your team, truly.

You use quotation marks above that you are ascribing to me that actually are not what I said....

As far as easier to get bent on Helium on a rapid assent than on air or Nitrox, well if you don't get that...you don't get that. Helium is a much smaller molecule, it gets in places quicker and out quicker. If forced to expand rapidly (like in a rapid assent)when in a place it got to quicker than the other gases discussed then it is more likely to cause damage. Your argument in relation to helium solubility compared nitrogen ( lipids solubility actually) has some grounding but isn't applicable, and as such when you base an argument on a incorrect assumption, the entire argument is false. Helium will really mess you up on quick assents, much more so than air and/or nitrox.

Anyway...it is what it is.

You are correct, I should remove the quotation marks.

 

[limeyx]

hate to say it Nick, but you're nuts

based on what reasoning?

That I am going to do my best to save a teammate, and if someone can convince me that shooting a team-mate to the surface rather than performing as fast a controlled ascent to the surface as possible is a better way, then I would change my mind ?

 

[Trimixgrog]

Oh you're right. Silly me, we never discussed anything about general techniques for rescue, or decompression in general in cave class. How mistaken of me.

And we never discussed mine or wreck or cave diving where there's an open water ascent/descent portion.

Nope. No never.

And no, I dont necessarily believe that I am more likely to take a severe hit with a rapid ascent on helium.

I am a Trimix instructor. God help you if you take a helium hit underwater. As any Trimix diver knows, it is 2.7 times faster than Nitrogen. So, it will hit you 2.7 times faster than Nitrogen. It is very unforgiving. Your helium deco stops are generally the deeper stops. So, if you should be unfortunate enough to take a hit, it will start while you are at a significant depth. Now, top this off with trying to drag up an unconscious buddy. If you survive the ascent you'll probably have these helium blisters on your body, especially at your shoulders. I guess surface support could help you, while they weren't trying to resuscitate your buddy. That is all the while you are passing in and out of consciousness from the pain.

For those who knew Dan, would know, that he would not want anybody to risk their lives in the event something went horribly wrong. Which it did. BTW Dan was diving on Trimix.

It is obvious that I'm not going to change any opinions here. I just wanted to share some info with you guys to stop some of this quibbling. Dan wouldn't like it, a bit....
Take care, and safe diving...

 

[TSandM]

Nick, you do some seriously deep dives and rack up some major deco. If you were facing an hour's decompression, would you surface with an unconscious buddy who is not breathing, and whose reason for being in that condition you don't know? I'm not sure I would. An hour's decompression is something you're unlikely to be able to blow down to less than 8 minutes and come out whole.

If someone is breathing, you do everything you can. If they aren't breathing and it's going to take you more than, say, ten minutes to get them to somewhere where their breathing can be assisted, then you really have to do a risk benefit analysis as to how much risk you are taking, and how much benefit to the diver you can expect to be.

These really are terrifying things to contemplate, and I think they bring home the seriousness of the decision we make to do dives with mandatory decompression, especially large amounts of decompression.

 

[limeyx]

Nick, you do some seriously deep dives and rack up some major deco. If you were facing an hour's decompression, would you surface with an unconscious buddy who is not breathing, and whose reason for being in that condition you don't know? I'm not sure I would. An hour's decompression is something you're unlikely to be able to blow down to less than 8 minutes and come out whole.

If someone is breathing, you do everything you can. If they aren't breathing and it's going to take you more than, say, ten minutes to get them to somewhere where their breathing can be assisted, then you really have to do a risk benefit analysis as to how much risk you are taking, and how much benefit to the diver you can expect to be.

These really are terrifying things to contemplate, and I think they bring home the seriousness of the decision we make to do dives with mandatory decompression, especially large amounts of decompression.

Indeed, it's a pretty horrific thing to contemplate, and I hope I never have to.


If someone is not breathing, then on what I would call a "tech1" type dive (maximum of 30 mins deco on 50% or 100%) I would do my best to get them to the surface at 30fpm (so 5 mins from 150)

Once you start exceeding that, then the decision definitely starts to change somewhat (in my mind)

From 200 I think i would try it if it was in the first 10-15 mins of the dive (again this is about 30 mins deco but now on 2 gases)

An hours deco (i.e. an hour on deco bottles) I am not going to try in most cases. I might try to get the diver shallower, but yes this is a very grim situation indeed.

If there are lots of other divers, or official support divers then this makes it an easier decision. For instance, on our last trip there were 24 divers all ascending and descending at various times which makes handing off a diver much easier.

Obviously a breathing diver is not only an easier choice (they are obviously alive) but you can probably take somewhat more time on the ascent (as long as they continue to breathe) on the deeper dives.

Our cave team mad a pact after cave1, that even if the victim isn't breathing, we would do everything we could to exit an unconscious diver as long as we didn't incur a serious chance of killing ourselves in the process.

EDIT: One other thing to make completely clear. My comments are regarding an unconscious diver that I am pretty sure was just fine the last time I checked on him (i.e. my buddy or someone I am on a dive with)

It's kind of hard for me to imagine a case where I just stumble on a diver with no reg in and/or not breathing, and whom I have no idea how long they were not breathing for but it's probably been a while.

 

[limeyx]

For those who knew Dan, would know, that he would not want anybody to risk their lives in the event something went horribly wrong. Which it did. BTW Dan was diving on Trimix.

It is obvious that I'm not going to change any opinions here. I just wanted to share some info with you guys to stop some of this quibbling. Dan wouldn't like it, a bit....
Take care, and safe diving...

I have tried to make it exceptionally clear that my comments are NOT related to what happened to Dan, partly because the facts are not (and may never be) completely known.

Th 2.7 times issue is not the only issue at play here, and making blanket "any"-type statements is not always the best way to phrase things.

 

[limeyx]

having said all that, here is one case in which the buoyant ascent *may* have saved someone, but it's unclear if they were or were not able to breathe at depth or just choked and ascended....

From a BSAC report

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December 1995 (96/026)

A pair of divers entered the water and descended a marker line. One diver experienced a free flowing regulator at the surface. This diver experienced increasing quantities of water in the second stage of the regulator as the descent continued. At 41 m nothing but water was available from this regulator and a pony cylinder was used. However the diver was unable to establish comfortable breathing due to the previous inhalation of water and a buoyant ascent was made using stab jacket and dry suit. One arrival at the surface the diver appeared unconscious, but once assisted back into the boat made a full recovery.

The second diver was unaware of this event and continued down to 48m before missing their buddy. This diver made an uneventful ascent.
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