My usual final stop deco mix is.....

[Mdemon]

Digs, I think John Bennet used pure He as part of his deco routine when he set the depth record.

I get the feeling from the thread that He is best at depth and O2 in the shallows.  Fancy the Trimix course later in the year - we can get the answers then?  

[DALESDIVER]

<font color='#FF0000'>Helium in deco mixes works, very well, replacing it totally on ascent can lead to some nasty vestibular problems. Why spike n2 when you dont need to, plus its not expensive compared to the problems of resolving decompression problems.
High o2 spikes are more dangerous, chasing high po2's is the last thing you want on deco, you are better using helium mixes for deco, 50/50 heliox is my choice for bailout on the box, followed by 80/20 heliox. So therefore these are my deco gases if I use o/c in a problem, it does not increase run times if you use the right type of software or understand how your body reacts to helium.
Typical gases for an o/c dive to 85m
B/gas &nbsp;12/55 &nbsp;even 12/70 &nbsp;depends on the day
deco/travel 1 &nbsp; 36/25
deco gas &nbsp; &nbsp; 2 &nbsp; 80/20

has worked for me for a long time with no probs, and am out of the water before the old 32 &amp; 80 mob....

[Pierre Farrugia]

<font color='#0000FF'>Hello,

I voted other, as I normally use 32% and 60%. But this year I will try to change to 80%, as this seems better. Anyone here uses 60% for deco? Anyone used to use 60% and changed to an other gas and why?

[Mdemon]

Hi Andy, thanks for that!

80/20 looks very interesting as a deco gas... &nbsp;

Digger, you/we/I DEFINITELY need that Trimix ticket. &nbsp;Got any spare time/cash over the summer? &nbsp;There's a couple of us so far...

[Fathoms Down]

Originally Posted by [b

Quote[/b] (Pierre Farrugia @ Mar. 29 2004,17:31)]Anyone here uses 60% for deco? Anyone used to use 60% and changed to an other gas and why?

I must admit I haven't ever used 60% as a deco mix as I don't tend to do enough deco to have to worry about the CNS hit deco'ing on 80% gives me. I'd rather get back on the boat and get a cup of tea into me &nbsp;

Seriously though, deco'ing on a moderate O2 mix can be of benefit if you are doing multiple, long deco dives over multiple days.

[bang-on]

<font color='#0000FF'>

Originally Posted by [b

Quote[/b] (DALESDIVER @ Mar. 29 2004,08:38)]Helium in deco mixes works, very well, replacing it totally on ascent can lead to some nasty vestibular problems. Why spike n2 when you dont need to, plus its not expensive compared to the problems of resolving decompression problems.
High o2 spikes are more dangerous, chasing high po2's is the last thing you want on deco, you are better using helium mixes for deco, 50/50 heliox is my choice for bailout on the box, followed by 80/20 heliox. So therefore these are my deco gases if I use o/c in a problem, it does not increase run times if you use the right type of software or understand how your body reacts to helium.
Typical gases for an o/c dive to 85m
B/gas  12/55  even 12/70  depends on the day
deco/travel 1   36/25
deco gas     2   80/20

has worked for me for a long time with no probs, and am out of the water before the old 32 &amp; 80 mob....

dalesdiver,
what software do you consider the 'right type of software' as i ran the following gases through a number of softare programs and the run times on the helium rich deco gases was a good bit longer.

85m  for 20 mins:
15/40 trimix                           12/55 trimix
50/50 nitrox                           36/25heliox                          
100% o2                                80/20heliox

92 mins  otu's 111                   114 mins otu's 118
cns 53.9%                              cns  44.5%

when using the 50/50 heliox and 80/20 heliox for o/c bailout from ccr the run times are also increased over  50/50 or 100%.
i do think helium is a 'friendly gas' but also has to treated correctly for decompression as it can also bend you.

cheers
barrie

[wreckweasel]

Barry,

As far as Im aware theres only one proggy available to numpties like us that credits for Helium use..... and that requires a special undocumented software switch.

Helium theory is something thats struggling to catch up with reality... and it seems to lack a significant, rigourous and defendable scientific study.

Not what you wanted to hear eh? &nbsp;

[bang-on]

<font color='#0000FF'>

Originally Posted by [b

Quote[/b] (zaksherlock @ Mar. 30 2004,23:17)]Not what you wanted to hear eh?  

zak,
you could say that  

when you say undocumented i assume you mean except to those who know?

being unable to write my own software program i am limited to the deco software thats available,although a fan of helium i am just a tad interested in the software dalesdiver is using?

cheers
barrie

[Andy Phillips]

There is a package in development that is supposidly a hybrid of various deco theories, but is mostly empirically derived.

It uses He in deco mixes, the idea being that a gentle gradient of a gas is better for you then a big one.

The person writing the software is going to send me an e-mail which states his theories and gives some data, he has said it will be OK to post it when I get it, give it a week or so and I will put it up on the site.

Andrew

[Mark Chase]

Originally Posted by [b

Quote[/b] (bang-on @ Mar. 31 2004,00:16)]

zak,
you could say that  

when you say undocumented i assume you mean except to those who know?

being unable to write my own software program i am limited to the deco software thats available,although a fan of helium i am just a tad interested in the software dalesdiver is using?

cheers
barrie

I have had a chat with a couple of lads who do this. They just dont tell the computer that there is He in the deco mix???

The caviat is they use 100% at te 6m stop to flush out any remaining He

The logic to their argument is that the He dosent make any negitave diferance and is probably benifisual to a faster deco. This is bassed on the WKPP reserch. This is combined with the compulsory use of deep stops, slow ascents and a high level of personal fitness.

If your brave enough you can just suck it and see. A He bend is a pain bend and easily treated with 02 at ambient presure so its not as high risk as the Ntrogen bend.

Personaly I am alergic to pain so I will just hang about a bit longer in the water.

Mark Chase