DAN deeper dive second ok under given conditions ?

Hello,

I heard and read that there is a DAN article that says that in
multiple diving , the second dive can be deeper given certain
conditions.

Can anyone tell me the exact link in the DAN website that publishes
these results?

Thanks,

Mario

On 31 Aug 2004 10:55:54 -0700, marmagi@hotmail.com (Mario) wrote:

>Hello,
>
>I heard and read that there is a DAN article that says that in
>multiple diving , the second dive can be deeper given certain
>conditions.
>
>Can anyone tell me the exact link in the DAN website that publishes
>these results?
>
>Thanks,
>
>Mario

Couldn't find anything like that at www.diverslertnetwork.org. I'd be
surprised to see them say something like that.

I'll dive reverse profiles if I have to. But I always add in a
"safety margin" (WTF that means) and won't bitch at anyone but me if I
do get hit.

Where did you hear such a claim.
--
dillon

When I was a kid, I thought the angel's name was Hark
and the horse's name was Bob.

"Mario" <marmagi@hotmail.com> wrote in message
news:472db9ab.0408310955.6775b062@posting.google.c om...
> Hello,
>
> I heard and read that there is a DAN article that says that in
> multiple diving , the second dive can be deeper given certain
> conditions.
>
> Can anyone tell me the exact link in the DAN website that publishes
> these results?

There was an article in Alert Diver a year or two ago on that subject.
Don't have my old issues to be more specific. Can't give you a link.

Dillon Pyron wrote:
>
>
> Couldn't find anything like that at www.diverslertnetwork.org. I'd be
> surprised to see them say something like that.
>
> I'll dive reverse profiles if I have to. But I always add in a
> "safety margin" (WTF that means) and won't bitch at anyone but me if I
> do get hit.
>
> Where did you hear such a claim.

DEMA a couple years ago. It's not new news.

Brian
Edmonton, Alberta

On 31 Aug 2004 10:55:54 -0700, marmagi@hotmail.com (Mario) wrote:
>Can anyone tell me the exact link in the DAN website that publishes
>these results?

As if!...
....DAN were an authority on decompression or dive safety.

Have you ever seen a DAN RDP?
Have you ever seen a DAN scuba certification card?
Have you ever seen a DAN decompression program?

THEY ARE AN INSURANCE COMPANY. GET THAT THROUGH YOUR HEAD.

They don't know shit about diving, except actuarially speaking.
Give 'em 10,000 divers and they'll tell you how many will die
or get hurt, and how many will buy DAN T-shirts. Don't look to
them for diving advice.

As to "Reverse Profiles", it's a non-issue.

The greatest minds in decompression all gathered together
several years ago at a "workshop" convened at the Smithsonian
and they asked: "Why".

Collectively, the likes of Wienke, Hamilton, Maiken, Powell, Baker
and many others, had no answer. They did not know of any research or
any basis for the prohibition, only that they were told that a long
time ago, by an instructor.

The advice is known as "Dive Lore". It's origin is simple as
well as the reason you would STILL FOLLOW IT.

Get out your RDP.

Consider a Limit Dive to 120' and a 60 minute surface interval.
Your second dive is to 60'. How long can it be?
Add the two together.

Now do it the other way around.
Consider a Limit dive to 60' and a 60 minute SI.
Your second dive is to 120'. How long can it be?

DOH! Only a Homer would do the deep dive second.

That's the basis for the lore, and the reason you will continue
to follow it. It's not a trick of the RDP. It's just the nature of
halftimes and multiple compartments. Doing the deep dive second
ALWAYS RESULT IN LESS TOTAL BT.

safe diving,

bullshark

In article <4j2aj0h7uum6evmoal69039iouersn7me9@4ax.com>,
bullshark <bullshark@gmail.com> writes:
...
>As to "Reverse Profiles", it's a non-issue.
>
>The greatest minds in decompression all gathered together
>several years ago at a "workshop" convened at the Smithsonian
>and they asked: "Why".
>
>Collectively, the likes of Wienke, Hamilton, Maiken, Powell, Baker
>and many others, had no answer. They did not know of any research or
>any basis for the prohibition, only that they were told that a long
>time ago, by an instructor.


Funny, I have one of Wienke's books at home, and not withstanding the
difficulty of reading Wienke's writing style and wading through his math,
it does a pretty good job of presenting a theortical explaination of why
micro bubles formed after a first dive will grow larger, faster if the
second dive is deeper.

However, practical experience falls to confirm this theory.

--
Charlie Hammond -- Hewlett-Packard Company -- Ft Lauderdale FL USA
(hammond@not@peek.ssr.hp.com -- remove "@not" when replying)
All opinions expressed are my own and not necessarily my employer's.

On Wed, 01 Sep 2004 13:57:56 GMT, hammond@not@peek.ssr.hp.com (Charlie Hammond) wrote:

>Funny, I have one of Wienke's books at home, and not withstanding the
>difficulty of reading Wienke's writing style and wading through his math,
>it does a pretty good job of presenting a theortical explaination of why
>micro bubles formed after a first dive will grow larger, faster if the
>second dive is deeper.

I have his books too. If you have read them then you will know that
his goal from the outset, is to create a mathematical model that reflects
dive lore as well physical principles. Prior models do not respond to
ascent rates, sawtooth, spikes, or other behaviors, and diver safety
relies on respecting "lore" to keep the tables safe.

The funny thing is, he had nothing to present at the workshop though
his book(s) were already in print. Of course, his model already responded
to deeper than previous a (not having the benefit of the workshop). The
lore was believed to be based on experience, prior to that. Now, he has
a vested in interest in keep that faith alive, since a whole bunch of people
have bought into his system "as is". He doesn't want to recant, or rewrite
or retest. It would cost a fortune

http://www.soc.soton.ac.uk/OTHERS/SDSC/dn1_00a.html

His "explanation" is theoretical musing about an underlying cause for
dive lore. What substance there is relates to "Crush" dives as first
dives. Well, a "crush dive" is over 100 meters, and I don't think I'm
going to meet the first condition.

>However, practical experience falls to confirm this theory.

safe diving,

bullshark

Hello,


> >Can anyone tell me the exact link in the DAN website that publishes
> >these results?
>
> As if!...
> ...DAN were an authority on decompression or dive safety.
>
> Have you ever seen a DAN RDP?
> Have you ever seen a DAN scuba certification card?
> Have you ever seen a DAN decompression program?

No it isnt their objective

>
> THEY ARE AN INSURANCE COMPANY. GET THAT THROUGH YOUR HEAD.
>

This isn't true either

> They don't know shit about diving, except actuarially speaking.
> Give 'em 10,000 divers and they'll tell you how many will die
> or get hurt, and how many will buy DAN T-shirts. Don't look to
> them for diving advice.
>

I dont agree

> As to "Reverse Profiles", it's a non-issue.
>
> The greatest minds in decompression all gathered together
> several years ago at a "workshop" convened at the Smithsonian
> and they asked: "Why".
>
> Collectively, the likes of Wienke, Hamilton, Maiken, Powell, Baker
> and many others, had no answer. They did not know of any research or
> any basis for the prohibition, only that they were told that a long
> time ago, by an instructor.
>

Isn't it strange that there isnt much research on this topic ? We go
to the moon and beyond and we dont know much about divign ? isnt it
strange?


> The advice is known as "Dive Lore". It's origin is simple as
> well as the reason you would STILL FOLLOW IT.
>
> Get out your RDP.
>
> Consider a Limit Dive to 120' and a 60 minute surface interval.
> Your second dive is to 60'. How long can it be?
> Add the two together.
>
> Now do it the other way around.
> Consider a Limit dive to 60' and a 60 minute SI.
> Your second dive is to 120'. How long can it be?
>
> DOH! Only a Homer would do the deep dive second.


Here I fully agree.

But still I am very surprissed that there not much known about diving,
this surprises me.


>
> That's the basis for the lore, and the reason you will continue
> to follow it. It's not a trick of the RDP. It's just the nature of
> halftimes and multiple compartments. Doing the deep dive second
> ALWAYS RESULT IN LESS TOTAL BT.

I fully agree on this, but would like so much more technical research
on diving !

Thanks for your discussion I apreciate it.

Mario