Rec Trimix

[lamont]

Ask lamont what the rec triox class was like . . .

go read any tech 1 report. subtract the decompression, subtract the line laying, and we got to wear our masks a little bit more than it sounds like they do. we got all the rest of the fun. i get *really* twitchy now if we thumb a dive and don't promptly start moving up in the water column

 

[dherbman]

I was hesitant to initially quote directly the post on gavin scooter list about He uptake and washout vs. N2, but I found it here re-posted in a forum accessible to everyone. I assume David's summary in the post is fairly accurate since no one posted to correct him in either forum, even though I'm sure there were others on those lists who attended the conference. Of course, the study itself remains unconfirmed until it's published in a peer reviewed journal, but if true then it would explain what the WKPP guys had been observing in their own dives.

And here's some more GI3 from Feb 2002 for those who are interested.

Do you think they are talking about 100' dives? I don't and I'm not sure if you can get here from there.

 

[*Floater*]

And your point is, Floater?

My point was simply to elaborate on my earlier posts. i.e. to provide a link that would be accessible to everyone to the post I had referenced earlier and to elaborate on George's thoughts on helium as they seem relevant to this thread.

If you choose to believe him, then aside from the cost, trimix or heliox would be pretty much ideal at all depths. In practice, I agree with some others that it's not worth the cost for shallow dives - at least not for me.

 

[Soggy]

But my point still remains that on many 80-100 ft. dives there is no point in using Trimix. That was the point of this thread.

...and on many dives in that range, there is a very good reason to dive trimix.

Have any of the naysayers here actually done a dive in the 80-100 ft range ON MIX? If you haven't, you don't have a leg to stand on in this discussion and are apparently so full of pride that you cannot admit you are impaired even at shallow depths. You'd be amazed at the difference. I did a wreck dive a couple weeks ago that I had done 20+ times prior and I remember so many more details about the dive that it is unbelievable. The minute you enter the water, you are narced. Minimizing that narcosis is a good thing. Who the heck cares if you can't do a CESA? There is never a reason to do a CESA. Every dive is a deco dive and requires a slow ascent and a couple stops or two. A dive on 30/30 is no different from a dive on 32% as long as you aren't an idiot and blow to the surface like a lift bag.

Sometimes I take mix, sometimes I take nitrox, sometimes I take whatever happens to be in my tanks because it can be made to work, but helium has only advantages over nitrox. Yes, it ongasses faster, yes it offgasses faster....it averages out so that the 'NDLs' are roughly the same (and decompression is faster) as long as you don't polaris missile yourself to the surface.

 

[TheRedHead]

go read any tech 1 report. subtract the decompression, subtract the line laying, and we got to wear our masks a little bit more than it sounds like they do. we got all the rest of the fun. i get *really* twitchy now if we thumb a dive and don't promptly start moving up in the water column

I think people are misunderstanding my point. Your class was s tech class. I just don't like the name "recreational triox."

 

[TSandM]

They aren't talking about 100 foot dives, but they are talking about using helium in the deco gas in the depth ranges we've been discussing.

And lamont's class was REC Triox. It was an intermediate in the GUE progression. It is NOT Tech 1 or Cave 1. It does NOT involve decompression or overheads. It just applies technical standards for skills to recreational divers, just as Fundies begins to do.

 

[Soggy]

I think people are misunderstanding my point. Your class was s tech class. I just don't like the name "recreational triox."

Your liking or not liking the name does not change what the class is...triox in recreational depths. Get over the name. It is what it is.

 

[lamont]

But my point still remains that on many 80-100 ft. dives there is no point in using Trimix. That was the point of this thread.

You'd find a lot of agreement. I've got 200 cu ft of 30/30 which has been sitting around for almost a month now waiting for a dive...

 

[TheRedHead]

Sometimes I take mix, sometimes I take nitrox, sometimes I take whatever happens to be in my tanks because it can be made to work, but helium has only advantages over nitrox. Yes, it ongasses faster, yes it offgasses faster....it averages out so that the 'NDLs' are roughly the same (and decompression is faster) as long as you don't polaris missile yourself to the surface.

I was just reiterating my instructor's argument of why incur deco when you don't have to? If you are diving off recreational charters on dives in that range, trimix is probably not going to be available anyway. Has nothing to do with pride. Just intellectual argument.

 

[Soggy]

I was just reiterating my instructor's argument of why incur deco when you don't have to?

You always have to incur a deco obligation. That's diving. What we refer to as NDLs are just where the decompression is built into the ascent and 'safety stop' (what a nice PC phrase).

Here is a dive I would do on 32% OR 30/30
100 - 30 mins
50 - 1 min
40 - 1 min
30 - 1 min
20 - 1 min
10 - 1 min

Is that deco?

If you think so, is this deco?
100 - 30 mins
15 - 5 mins