Who's using 100% O2 for deco?

[Jax]

"in a sick way" :w-t-f: uh, huh. I also noted it was updated as of Jan this year.

Actually, it's easiest to get an 80% fill, and v-planner doesn't show a hit. Maybe if I were to do those hour-long hangs y'all do, but I'm not there.

 

[lowviz]

:cool3:

Seems one could plan their own deco gasses without the dictation of others as to what they should or should not use. That is, if one really knows how to plan their gas, and knows themselves as an individual.

Yes, you can spike 2.0 for 1 minute at your first deep stop then progress at 1.6 at planned depths. Going tech will give you endless ways to dance with the devil, you will love it -endless calculations.... :cool2:

 

[ianr33]

I was under the impression that air breaks had much more to do with CO2 than PO2...

No, Air Breaks are totally to keep oxygen exposure under control.

 

[Rainer]

Well, that misses some of the reasons many of us standardize on particular gases. That's different than the "why O2" question.

(1) If everyone has the same deco gas(es), it means we get to deco together. Since gas switches are probably the most dangerous part of a "tech dive", I know *I* (and all those I dive with) want to be together with the team for all the decompression. If one person shows up with 80% and another with O2, we're going to be doing our switches (and deco) apart. For some of us, that's a non-starter.

(2) Picking a small set of gases let's you minimize one of the variables in decompression (i.e. gas choice). This leads to a better understanding of how you personally deal with varying deco schedules. If you use different gases all the time, you don't get to build up that inventory of constrained experience.

(3) Standardizing on gases can allow you to standardize on decompression schedules (e.g. Ratio Deco). Again, that just means minimizing deco variables (you are now holding constant the type of ascent and gases used for a particular depth/BT combination). Doing so can help you hone in faster as to what works and doesn't work deco-wise for your personal physiology.

Those are just some of the reasons many of us choose NOT to vary what deco gases we use on a whim.

As to why O2, for me it mostly comes down to: (1) no inert component, (2) fitting in with other deeper deco gas choices, (3) standardization, (4) ease of access (no blending required), and (5) a good personal history with it.

:cool3:

Seems one could plan their own deco gasses without the dictation of others as to what they should or should not use. That is, if one really knows how to plan their gas, and knows themselves as an individual.

 

[Atticus]

So, you're saying the reason to use 100% is because everyone else is . . . ?

Hi Jax,

I was responding to the original poster, but due to the timing of when our posts went up it looks like I was responding to you. I was not trying to tell you to use 100% because everyone else does. In fact, not everyone else does, just most everyone I happen to know

Rainers post covers the reasons I choose 100% - no inert gas and standardization amongst DIR trained divers. That being said it's not a religion - I've been known to commit such heresy as deco'ing on air. It just takes forever and I never feel as good afterward.

 

[DevonDiver]

I use what is available - more often than not, that means 100%.

I'm a poor diving instructor, living in Asia...so cost does enter the equation, as does availability.

If I lived in the USA, or Europe,with a well-paid regular job and diving was a weekend indulgence, then my outlook would possibly be different.

 

[vladimir]

I'm a [-]poor[/-] great diving instructor, of limited means, living in Asia...so cost does enter the equation, as does availability.

Fixed that for you, Andy.

 

[Tortuga68]

I use what is available - more often than not, that means 100%

If 100% is available, then 21-99% is available as well

Re: the OP, I use 50% and 100%.. the basic premise of AN is accelerated decompression; 100% accelerates deco faster than <100%

 

[DevonDiver]

If 100% is available, then 21-99% is available as well

Theoretically, yes - but there can be cost/logistical hinderances.

I used to dive on a tech liveaboard in Thailand. They had 100% surface supplied at 6m, from a huge bank. That's what they supplied.

With the deeper mixes, it can be easier to plan a dive going onto a 'rec' mix deeper, than to insist on >40% mixes. I've used 32% as my first mix on many occasions - it's much more obtainable, and usually cheaper, especially when a dive op has it banked/stored.

 

[waterpirate]

I prefer 70% for a single deco gas mix for 60 min runtimes. On your deco gas sooner and low risk of maxing your cns clock, no air breaks. If going deeper longer it gets more interesting. I wil carry two deco gasses and add helium, but still finish with 70%. I prefer to go to a rec mix of 32/20 for deco mix one rather than say a 50%. In the end it is all personal choice. Once you enter tech their are no hard rules save the ones you apply to yourself, or the team adopts.
Eric