Not diving to greater than 30m/100ft unless with helium

[Tassi Devil Diver]

Since I have been diving rebreather any dive over 30m (100ft) I use helium in my diluent and generally keep my END to around 25m for deeper dives, not only because using He in a rebreather is more economical, but I don't want to be in any situation where I could confuse the onset of a CO2 hit with narcosis or have narcosis impair my ability to react to issue on the rebrather, plus I don't miss those feelings of impending doom I got from time to time when diving deeper on air. Thank god those days are long behind me.

 

[100days-a-year]

Maybe some people need all their faculties super sharp just to deal with the insurmountable complexity of a reef dive,no shame in that.Just because most of the world is perfectly content and capable up to 30m 100ft on air or nitrox doesn't mean that some people either start out with less ability to be cognizant of the multitudinous tasks entailed in a single tank dive in warm water guided by a DM or are so impaired by the merest whiff of a narcotic gas that they become a certain fatality at depths greater that 0.

 

[Lorenzoid]

Maybe some people need all their faculties super sharp just to deal with the insurmountable complexity of a reef dive,no shame in that. . . .

Sarcasm aside, suppose the diver is a fish biologist or just an enthusiast and wants to remember in exact detail what he saw? Okay, so such a diver probably has a camera. I do not, and try as I may, I believe I have more more difficulty remembering details than I would on the surface. If something (other than a camera) would help me recall more detail, I would be interested in it.

 

[dumpsterDiver]

Sarcasm aside, suppose the diver is a fish biologist or just an enthusiast and wants to remember in exact detail what he saw? Okay, so such a diver probably has a camera. I do not, and try as I may, I believe I have more more difficulty remembering details than I would on the surface. If something (other than a camera) would help me recall more detail, I would be interested in it.

LOL.. A Fish Biologist !!!!! They are poorer than DIRT! They sure as heck aren't going to be using expensive helium in 100 ft!

 

[100days-a-year]

Sarcasm,Moi?It is, sadly, my bodies natural defense against a host of ailments.

We've heard from long term professional divers that have had no issues doing extremely complex and strenuous tasks at various shallower depths without HE.
I know LEO recovery divers,golf ball divers,commercial divers from bridge to rigs,Navy divers,commercial spearfishermen(like me) and not one uses HE shallow unless somebody else pays for it.Now either my cohort of acquaintances is comprised of geniuses or those whose recreational use of mind altering substances has given them so degree of tolerance or this entire issue is blown way out of proportion in shallow depths.Maybe there are some very few who are severely impacted at shallow depths but I haven't met one and if I do will not dive with them as I think it may be indicative of deeper issues that I frankly don't care to be caught up in.

 

[Lorenzoid]

So if helium cost no more than oxygen, all of you would be using it.

 

[decompression]

So if helium cost no more than oxygen, all of you would be using it.

So, deep/technical diving isn't the place to be cheap............interesting.[emoji6]


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[Storker]

So if helium cost no more than oxygen, all of you would be using it.

I can't of course speak for all the others, but I would probably consider it quite seriously. I know that I'm starting to get a little tipsy somewhere between 25m and 30+m. A clear head and a lower WOB for the same price as nitrox sounds tempting.

With the reservation that I don't know anything about trimix NDLs, a tank of 21/15 would give me similar nitrogen loadings as a tank of EAN36 without the concern for MOD, and less narcosis. That sounds very much like a win-win to me, but I'd have to take a (hypothetical?) rec trimix course to be sure that my thinking is sound...

 

[Eric Sedletzky]

This thread is hysterical.
But then with a title like "Not diving deeper than 100 ft. unless with helium", It figures the type that would be attracted to such a title.
Hence the fanaticism.

 

[KenGordon]

With the reservation that I don't know anything about trimix NDLs, a tank of 21/15 would give me similar nitrogen loadings as a tank of EAN36 without the concern for MOD, and less narcosis. That sounds very much like a win-win to me, but I'd have to take a (hypothetical?) rec trimix course to be sure that my thinking is sound...

Weak trimix deco is approximately like air deco. If you assume the he behaves like o2 you would be taking quite a risk.

For example 25 minutes at 30m is a no stop dive for 36% (with minor MOD breakage) but likely to have significant stops > 10 minutes on air or 21/15 depending on model, settings etc.