Who's using 100% O2 for deco?

[Jax]

For all of my early tech training we used 100%. That training was DIR, and we knew the Baker's Dozen rant, although we did not pay a lot of attention to it specifically.

For a variety of reasons I finished my trimix training through TDI. I was quite amused in reading the TDI textbook about this topic. In the section where they say it doesn't matter which you use, there is a reference to some people "beating their chest" and raving about only using 100% O2, and the way it was written, it was very clearly a direct response to Irvine's Baker's Dozen rant. I sent the Baker's Dozen to my TDI instructor, who had never seen it and was quite amused.

In my TDI training in South Florida, we used nothing but 80%. The local fill shop banked it. I did a lot of dives during that period, and there were always other deco divers on the boats with us. I believe every one of them used 80%.

I will use whatever my team wants to use without giving it a second thought.

:cool3:

This is exactly what I appreciate about ScubaBoard. One may study all the books and authoritative sources you wish, but you just don't get the reasoned opinions and diverse outlooks that you can get here. It's a form of mentorship that just is not availalbe in low-density diver populations.

 

[MXGratefulDiver]

I really do not understand gravity but I keep using it all the time. Does that make me dangerous?

... only if you fall on somebody ... :shocked2:

... Bob (Grateful Diver)

 

[jimmy71]

:cool3:

This is exactly It's a form of mentorship that just is not availalbe in low-density diver populations.

Funny all the areas i dive are full of dense divers

 

[Jax]

Funny all the areas i dive are full of dense divers

:spit:

 

[ajduplessis]

I use 100% O2 for all my shallow deco obligations with switches to backgas where needed.

 

[ucfdiver]

As for DIR (Irvine), I'm not finding I agree completely with the way they do some things.

A couple buddies and I dove with him a few weeks ago and he's pretty flexible with plans when safety isn't compromised unnecessarily. He's pretty opinionated about procedures that he and his dive buddies developed, but is also very willing to learn. It was actually quite interesting hearing him share the volume of people he contacted before forming his final decision on how he chose to dive.

The ideas he presented in that message board posting (it was NOT an article he published-- just a posting) were fairly well justified opinions, with a few slap shots muddling the more quality bullet points.

Because I am questioning this "we all do 100% . . . . because we all do 100%" mentality?

I feel the same way about having to drive on the right hand side of the road....silly standardization.

I will use whatever my team wants to use without giving it a second thought.

Does it concern you at all hopping gases around so you can't monitor your body's feedback (ie sub clinical symptoms)?

 

[boulderjohn]

Does it concern you at all hopping gases around so you can't monitor your body's feedback (ie sub clinical symptoms)?

Why would using 80% on some dives and 100% on others have that effect? Why is that preventing me from monitoring my body's feedback?

 

[ucfdiver]

Why would using 80% on some dives and 100% on others have that effect? Why is that preventing me from monitoring my body's feedback?

Seems like a 30% change in pressure added from the water's surface is significant change on bubble tension.

I'm not sure what difference it makes since I've never tried it, but I like keeping things standard.

 

[Jax]

Seems like a 30% change in pressure added from the water's surface is significant change on bubble tension.

I'm not sure what difference it makes since I've never tried it, but I like keeping things standard.

Sorry, not following. Do you mean because the swap is made at 2 ATAs instead of 1.6 ATAs? One would still do the planned deco at that level as called for by whatever tables one uses (electronic, software, or other). Would you please clarify for those of us less experienced?

 

[ucfdiver]

Sorry, not following. Do you mean because the swap is made at 2 ATAs instead of 1.6 ATAs? One would still do the planned deco at that level as called for by whatever tables one uses (electronic, software, or other). Would you please clarify for those of us less experienced?

Well, by moving the 1.6ppo2 switch to 30ft you've

• reduced the amount of time your body is given to lower it's CNS load from the 70 bottle switch, so possibly changing how much vascularconstriction your body has gotten rid of (I have no idea how this would change how my body reacts)
• reduced the bubble tension of your last stop (I have no idea how this would change how my body reacts)
• Added another chance to have an error in filling or labeling a tank (Unless you have dedicated 30 and 20ft tanks)

I don't see as much of an issue using 80% as your team's standard gas as I do changing dive in and dive out. Most of us barely deco dive enough to get a firm grasp of our body with just 70/20 bottles, so I don't think adding even more gases is a great idea. I won't go as far as George did and say you're an unsafe diver if you have a different gas, but I do believe that having a different gas has some clear drawbacks.

IMO Too often people want change for the sake of change and don't realize the downsides associated with it. Look at our current president for an example outside of diving.