Anybody remember this thread? Nov. 2000 uk.rec.scuba

I posted this question 4 years ago. I wonder if you guys have had enough
time to figure out an answer?

cheers, Mark ;->

p.s. enjoy the thread - I think the last post is the best - "Doh"

p.p.s. No, I never did receive any answer to my question


=== === === === ====
All messages from thread

Message 1 in thread
From: wjmark (wjmark@mbnet.mb.ca)
Subject: 'bends' question - help please
Newsgroups: uk.rec.scuba
Date: 2000-11-22 17:21:34 PST


Hi,

I just saw a documentary on a diving to look at an old U-boat. While
filming this show, two divers ran out of air at 60m.

So they cut their equipment and surfaced. One died almost immediately, but
the other lived a few (agonizing, I suppose) hours before dying in a
decompression chamber on the mainland.

MY QUESTION: Couldn't they have just strapped another tank on him and
slapped him back down into the deep... ?

I know so little about diving, that I don't even know if it's a silly
question.

If someone could reply directly to my email address, that would be great --
I don't follow this newsgroup...

Cheers,

Mark

=== === ===
message 2 in thread
From: Big Frank (frank@airflow.DOT.net)
Subject: Re: 'bends' question - help please
Date: 2000-11-22 18:49:11 PST


wjmark <wjmark@mbnet.mb.ca> wrote in message
news:01c04ecd$52c6db00$87aac5d1@leah...
> Hi,
>
> I just saw a documentary on a diving to look at an old U-boat. While
> filming this show, two divers ran out of air at 60m.
>
> So they cut their equipment and surfaced. One died almost immediately, but
> the other lived a few (agonizing, I suppose) hours before dying in a
> decompression chamber on the mainland.
>
> MY QUESTION: Couldn't they have just strapped another tank on him and
> slapped him back down into the deep... ?
>
> I know so little about diving, that I don't even know if it's a silly
> question.
>
> If someone could reply directly to my email address, that would be
great --
> I don't follow this newsgroup...

Not a lot of point posting a message here then is there? Chances are this
message will generate quite a bit of activity but you're going to miss it
all...
--


Frank

-------------------------------------------------------------
"Somewhere, I suspect, I am depriving a village of an idiot!"
-------------------------------------------------------------

=== === ===
Message 3 in thread
From: Michael K. Schiltz (mks1717@hal-pc.org)
Subject: Re: 'bends' question - help please
Date: 2000-11-22 22:20:11 PST


What was the camera team doing?

wjmark wrote:

> Hi,
>
> I just saw a documentary on a diving to look at an old U-boat. While
> filming this show, two divers ran out of air at 60m.
>
> So they cut their equipment and surfaced. One died almost immediately, but
> the other lived a few (agonizing, I suppose) hours before dying in a
> decompression chamber on the mainland.
>
> MY QUESTION: Couldn't they have just strapped another tank on him and
> slapped him back down into the deep... ?
>
> I know so little about diving, that I don't even know if it's a silly
> question.
>
> If someone could reply directly to my email address, that would be
great --
> I don't follow this newsgroup...
>
> Cheers,
>
> Mark

=== === ===
Message 4 in thread
From: robert.lethbridge (robert.lethbridge@ntlworld.com)
Subject: Re: 'bends' question - help please
Date: 2000-11-23 06:01:18 PST


Just finished reading "The Last Dive" which documents the careers of the two
divers concerned, have'nt seen the documantary (missed it). At the time
there was no camera crew present and the detail of events that led to their
death has been put together from available evidence.

I'd be gratefull if anyone can let me know if they have a video of that doc
as I'd very much like to see it.

Rob

=== === ===
Message 5 in thread
From: Cliff Coggin (clifford@ccoggin.freeserve.co.uk)
Subject: Re: 'bends' question - help please
Date: 2000-11-23 14:45:11 PST


wjmark <wjmark@mbnet.mb.ca> wrote in message
news:01c04ecd$52c6db00$87aac5d1@leah...

>
> If someone could reply directly to my email address, that would be
great --
> I don't follow this newsgroup...

If you can't be bothered to read the newsgroup, why should we bother to
reply?

Cliff.

=== === ===
Message 6 in thread
From: Dan (d.uren@seascapescuba.com)
Subject: Re: 'bends' question - help please
Date: 2000-11-30 05:27:02 PST


So why bother Cliff.... (LOL)

Dan

Cliff Coggin <clifford@ccoggin.freeserve.co.uk> wrote in message
news:8vk6ll$3ml$1@newsg3.svr.pol.co.uk...
>
> wjmark <wjmark@mbnet.mb.ca> wrote in message
> news:01c04ecd$52c6db00$87aac5d1@leah...
>
> >
> > If someone could reply directly to my email address, that would be
great --
> > I don't follow this newsgroup...
>
> If you can't be bothered to read the newsgroup, why should we bother to
> reply?
>
> Cliff.


=== === ===
Message 7 in thread
From: Robert work (robert.white@eanx.freeserve.co.uk)
Subject: Re: 'bends' question - help please
Date: 2000-11-30 12:24:07 PST


did anyone consider answering the question?
or shall I reply to him saying "Doh! If only they'd thought of that"

wjmark wrote:

> I just saw a documentary on a diving to look at an old U-boat. While
> filming this show, two divers ran out of air at 60m.

As in the book "The Last Dive".

> So they cut their equipment and surfaced. One died almost immediately, but
> the other lived a few (agonizing, I suppose) hours before dying in a
> decompression chamber on the mainland.
>
> MY QUESTION: Couldn't they have just strapped another tank on him and
> slapped him back down into the deep... ?

It's been done with variable success. Since being bent often causes
blackouts they'd drop the reg and drown often enough for it not to be
considered a worthwhile idea. You'd loose more divers that way than
calling for a helicopter evacuation every time.

> If someone could reply directly to my email address, that would be great --
> I don't follow this newsgroup...

Can't be bothered. By then that was 4 years ago.

The book annoyed me. A lot of it was spent pointing out how cave diving
techniques were good on wrecks but it was a cave technique (staging
deco gas) that killed them. With a wreck there is not just one way back
to the surface. The author had had the same problem earlier but they
learnt the wrong lesson from that incident and tried to emulate his
lucky escape rather than ask what went wrong with the system.

nigelH

"wjmark" <so_long@ago.eh> wrote in message
news:4Onhc.51292$Gp4.1165081@news20.bellglobal.com ...
> p.p.s. No, I never did receive any answer to my question
Maybe because you said you didn't want to bother to read the newsgroup!

> MY QUESTION: Couldn't they have just strapped another tank on him and
> slapped him back down into the deep... ?
From my understanding of decompression theory, there's a few problems with
that.
Firstly, once you've formed serious bubbles they're much harder to get rid
of - meaning that the dive would have to be increadibly deep.
Secondly, the diver would probably quickly blackout, and so drop their
regulator and drown - so in-water recompression is only an option with a
full face mask.
Thirdly, they won't have enough oxygen on the boat for oxygen recompression
so they'd need to use air recompression tables - the only source of in-water
tables I have is the US Navy ones. According to Air Treatment Table 3 (which
I think might be appropriate but I don't know and I'm not particularly
inclined to read the entire chapter to work it out - it's just an example)
you could require (25litres/min SAC):
30 minutes at 165 feet (4463 litres)
12 minutes at 140 feet (1560 litres)
12 minutes at 120 feet (1380 litres)
12 minutes at 100 feet (1200 litres)
12 minutes at 80 feet (1020 litres)
30 minutes at 60 feet (2100 litres)
30 minutes at 50 feet (1875 litres)
30 minutes at 40 feet (1650 litres)
720 minutes at 30 feet (34200 litres)
120 minutes at 20 feet (4800 litres)
120 minutes at 10 feet (3900 litres)
165 minutes for ascending no faster than 1 ft/minute (14334 litres)

So total air requirement at this increadibly convenient (and low for a full
face mask) value is 72482 litres. So with 232 bar tanks that's going to mean
needing 312 litres of tanks.
Twin 156s anybody? (a 'standard' tank is 12 litres)

That's not to mention the kind of support you need to do a 21 and a half
hour dive.

Alun Harford

"Alun Harford" wrote

> Thirdly, they won't have enough oxygen on the boat for oxygen
recompression
> so they'd need to use air recompression tables - the only source of
in-water
> tables I have is the US Navy ones. According to Air Treatment Table 3
(which
> I think might be appropriate but I don't know and I'm not particularly
> inclined to read the entire chapter to work it out - it's just an example)
> you could require (25litres/min SAC):
> 30 minutes at 165 feet (4463 litres)
> 12 minutes at 140 feet (1560 litres)
> 12 minutes at 120 feet (1380 litres)
> 12 minutes at 100 feet (1200 litres)
> 12 minutes at 80 feet (1020 litres)
> 30 minutes at 60 feet (2100 litres)
> 30 minutes at 50 feet (1875 litres)
> 30 minutes at 40 feet (1650 litres)
> 720 minutes at 30 feet (34200 litres)
> 120 minutes at 20 feet (4800 litres)
> 120 minutes at 10 feet (3900 litres)
> 165 minutes for ascending no faster than 1 ft/minute (14334 litres)
>
> So total air requirement at this increadibly convenient (and low for a
full
> face mask) value is 72482 litres. So with 232 bar tanks that's going to
mean
> needing 312 litres of tanks.
> Twin 156s anybody? (a 'standard' tank is 12 litres)
>
> That's not to mention the kind of support you need to do a 21 and a half
> hour dive.

Not all that long ago, I did quite a bit of research on the concept of in
water recompression. Aside from the issues you raise, I concluded something
interesting. For a diver that's simply blown his decompression schedule, is
not yet bent, or is only showing the first symptoms of being bent, in water
recompression may be a viable way to slow the dcs process until real help
can arrive. Ascending back to depth while more effective medical help is on
the way, might be a useful way to limit the damage resulting from making the
mistake in the first place.

In general, I'm not a fan of in water recompression. On the other hand,
it's just one more tool in the box that, when all else fails, might make the
difference between life and death or recovery versus permanent disability.

Lee

"wjmark" <so_long@ago.eh> wrote in message
news:4Onhc.51292$Gp4.1165081@news20.bellglobal.com ...
> I posted this question 4 years ago. I wonder if you guys have had enough
> time to figure out an answer?
>

Yes thanks. Have you?

Cliff.

On Wed, 21 Apr 2004 06:40:02 +0000, Nigel Hewitt wrote:

> The book annoyed me. A lot of it was spent pointing out how cave diving
> techniques were good on wrecks but it was a cave technique (staging deco
> gas) that killed them. With a wreck there is not just one way back

It's like when people go one about rule of thirds for deco diving in open
water. In a cave, you need a third in reserve (or more really) to get you
and your buddy back to the entrance. In open water a third might be far
more or far less than you need for your collective deco. It's irrelevant.
You need to work out your reserve properly.

Jason

--
See http://www.scuba-addict.co.uk/ to view UK dive spaces or add your own.

> Hi,
>
> I just saw a documentary on a diving to look at an old U-boat. While
> filming this show, two divers ran out of air at 60m.
>
> So they cut their equipment and surfaced. One died almost immediately, but
> the other lived a few (agonizing, I suppose) hours before dying in a
> decompression chamber on the mainland.
>

A local dive guide in Truk ran out of air at 60m and bolted for the surface
while I was there last October. Carried into the chamber unconcious and in
need of the occasional puff of air and walked out again......amazing really.

Paul

> > MY QUESTION: Couldn't they have just strapped another tank
> > on him and slapped him back down into the deep... ?

> Firstly, once you've formed serious bubbles they're much
> harder to get rid of - meaning that the dive would have to be
> increadibly deep.

Why? Why not 18m on O2 with a full face mask? (Hint: that's what they use
for a standard chamber treatment)

> Secondly, the diver would probably quickly blackout, and so
> drop their regulator and drown - so in-water recompression is
> only an option with a full face mask.

Not true.

> Thirdly, they won't have enough oxygen on the boat for oxygen
> recompression

Why do you assume this? Surface-supplied O2 via FFM is an option used on
some boats that operate at a distance from recompression facilities.

Having significant on-board O2 allows you to use one of the various methods
described. The "Australian" method is a 30-90m dive to 9m on O2 (in the case
under discussion, I imagine that the 90min dive would be used), followed by
a 1m/12min ascent. Total run-time of 198min, total gas consumption (assuming
25L/min) 8190L.

> That's not to mention the kind of support you need to do a 21
> and a half hour dive.

Which is why O2-based IWR would be the realistic option.

Iain

"Phil S" wrote

> > Why? Why not 18m on O2 with a full face mask? (Hint: that's what they
use
> > for a standard chamber treatment)

> Oxygen toxicity. A chamber is dry, the patient can be warm and completely
at
> rest with intravenous infusion, there are air breaks and there is medical
> backup. In any case, the IWR method you refer to below is done at 9m, not
> 18m.

I don't think I've seen anybody recommend in water recompression as a
preferred method when there's a chamber available. Further, the 18 meter
equivalent for "standard chamber treatment" is not IWR, it's chamber
treatment . . . and it's correct.

> > > Secondly, the diver would probably quickly blackout, and so
> > > drop their regulator and drown - so in-water recompression is
> > > only an option with a full face mask.
> >
> > Not true.
>
> A deep, rapid ascent, as in the original example, may well be followed by
> impaired consciousness, nausea, or vomiting, which are all
contraindications
> to IWR.

Beats death every time. Let's not lose track of the fact that this is a
thread that started with one diver dead on the spot and another dying in the
chamber. Use of a full face mask is specifically for the purpose of dealing
with possible oxygen toxicity as well as unconsciousness.

Lee

Lee Bell wrote:
> I don't think I've seen anybody recommend in water recompression as a
> preferred method when there's a chamber available.

Absolutely, when there is a chamber available, use the chamber. But there
are many places aroudn the world where a chamber isn't available. In these
cases IWR is the only option...

Al.