deep air

[DCBC]

CO2 is the biggest enemy of the RB diver and since it is known to exacerbate the symptoms of narcosis I need to avoid both as much as possible.

I agree with your comments. It has been a few years since I've actively used a RB; from time-to-time in the Navy (mostly outside of the air envelope) and most recently, as a bailout system for deep saturation.

 

[DCBC]

DCBC, we're on the same page when it comes to too much, too soon! I feel the same way about "zero to hero" cave classes. Helium may, indeed, make it seem all too easy to go very deep before someone has the diving experience to make it reasonable to do so. But the helium isn't at fault -- it's the diver's (and his instructor's) decision-making that's the problem. Using narcosis as a way to scare people into taking it slowly seems like a dubious proposition to me.

The problem (as I see it) is that the inexperienced diver is given the option in the first-place. Years ago, this was never the case. All the rules seem to have been thrown out the window and it's a free-for-all. People now are allowed to arm themselves with a little bit of knowledge and personally I think that this is asking for trouble.

I've never seen narcosis used in the manner that you describe. Scare tactics are evidence of poor instruction imo.

Dealing with narcosis and having to problem solve in emergent conditions makes a better prepared diver for deeper dives. I have no doubt of this.

As you are aware, nitrogen is not the only gas that may be involved in inert gas narcosis. Other gases present unique problems to the diver as well. Dealing with nitrogen narcosis has assisted me in understanding how my body is reacting adversely to other conditions; allowing me to report problems or to hold it together long enough to take action.

 

[Blackwood]

The problem (as I see it) is that the inexperienced diver is given the option in the first-place. Years ago, this was never the case. All the rules seem to have been thrown out the window and it's a free-for-all.

While I wasn't diving years ago (at least not in the time scale I think you're using), I have to question that.

You seem to belittle (or perhaps just poke fun at) divers who use helium to go to 160 feet with little experience. Would you really they make those dives on air with the same lack of experience?

On the one hand I agree with you. Diving is a progressive activity. You require progressively more experience the deeper you go. On the other hand, you seem to be suggesting that having access to hypoxic trimix (for example) means that an unqualified diver is necessarily going to go to 300 feet, but that restricting access to that same gas will somehow prevent the same unqualified diver from going to 300 feet. In my book, you're gunna to what you're gunna do.


At the end of the day, we're adults and it's up to the individual diver. Yes, you can go to 330' on an advanced trimix cert. You can also go to 330' on an air cert. Or on no cert. If someone is willing to do something stupid, that's on them. Personally, even at these moderate depths (i.e. 160'), I prefer the noticeable* clearheadedness of helium.

*I went from 32% in a stage to 25/15 in my backgas (because it's what I had in my garage) at about 100 feet last weekend, and I could tell the difference, or at least experienced placebo effect.

 

[gcbryan]

Isn't this argument a bit like comparing race cars to station wagons. If you are on the race track you need the race car but if you are going cross country you need the station wagon or you will be spending most of your time getting your car repaired. A race car is too delicate for long cross country driving.

You can yourself become so finely balanced and delicate that if you don't have reels,scooters,helium on a dive you might just fall apart. As a diver you need to be robust as well.

Being cave certified when you can't do a lesser dive in a more robust manner may crop up to bite you one day. I may be wrong but I don't think anyone is suggesting that most cave and wreck divers today should be doing so without some helium in the mix.

Surely a robust diver should be capable of diving down a wall to 150 fsw or greater on air. Surely the risks are greater cave diving even with helium in the mix than air diving on a wall at 150 fsw. Why not acknowledge that rather than be so absolute in one's thinking.

I can tell the difference when I have 10 hours sleep from when I have 8 hours sleep but I wouldn't argue just because I can tell the difference that I can't safely function without 10 hours sleep.

 

[DCBC]

...You require progressively more experience the deeper you go. On the other hand, you seem to be suggesting that having access to hypoxic trimix (for example) means that an unqualified diver is necessarily going to go to 300 feet, but that restricting access to that same gas will somehow prevent the same unqualified diver from going to 300 feet. In my book, you're gunna to what you're gunna do.

I don't know many divers that dive air past 130'. Many divers could, but they don't because of the narcosis barrier. These same divers will dive trimix at 200' or more. You can eliminate the chance of narcosis and put the same inexperienced diver 100' deeper. Does this makes sense to you? If it wasn't for trimix the diver would be on the reef at 100' gaining experience.

I've made my living breathing heliox, so obviously I don't have any problems with diving deep, but the diver should be experienced and properly trained to do the dive. This doesn't matter what the mixture is. If a diver can't dive air safely at the maximum sport diving limit of air, what makes anyone think he can safely dive to 330' on trimix? Because of the narcosis? There's a lot more to deep diving than narcosis and if the diver doesn't realize that, I question if he should even be in the water.

Giving a diver an advanced trimix card good to 330' when the deepest the diver has been before certification is 180' (twice in his life, both with an Instructor? Beam me up Scotty....

I'm not talking about what a person can do. We can all find interesting ways of killing ourselves if we want to, but to give the impression that someone is qualified? Come on.

 

[MaxBottomtime]

Isn't this argument a bit like comparing race cars to station wagons. If you are on the race track you need the race car but if you are going cross country you need the station wagon or you will be spending most of your time getting your car repaired. A race car is too delicate for long cross country driving.

Exactly, and as DCBC aluded to, I wouldn't let someone drive a race car on a track if they hadn't already driven fast in a street legal car.

 

[Rainer]

you wouldn't dive stoned.

Nope.

You can think what you wish to think, but that doesn't make it true.

Glad you recognize that, but please, keep prattling on. It's amusing.

Again you show your ignorance, the 50' depth limit has been proven by various hyperbaric research facilities.

Citations? And no, you don't need to PM me. You can post in public. Feel free to ignore the irony of your "proven limit" that you feel doesn't then somehow apply to 250' air dives. You're a riot.

Any emergency ascent would be to the bottles not the surface.

LOL, you rock on with your CESAs to your next bottle. Too funny.

logic escapes me.

No kidding.

 

[TSandM]

Surely the risks are greater cave diving even with helium in the mix than air diving on a wall at 150 fsw. Why not acknowledge that rather than be so absolute in one's thinking.

Yes, the risks are greater cave diving than open water diving -- I think. But honestly, I don't think I have to do a dive to 150 feet while fuzzy and stupid in order to feel that I can competently execute a cave dive, especially a cave dive to a shallower depth. I HAVE done a couple of dives to the 150 foot range -- I did them on mix, in extremely favorable conditions, and they went well. I have no desire at all to see how they go when I'm not firing on all cylinders.

 

[Blackwood]

I don't know many divers that dive air past 130'. Many divers could, but they don't because of the narcosis barrier. These same divers will dive trimix at 200' or more. You can eliminate the chance of narcosis and put the same inexperienced diver 100' deeper. Does this makes sense to you? If it wasn't for trimix the diver would be on the reef at 100' gaining experience.

I've made my living breathing heliox, so obviously I don't have any problems with diving deep, but the diver should be experienced and properly trained to do the dive. This doesn't matter what the mixture is. If a diver can't dive air safely at the maximum sport diving limit of air, what makes anyone think he can safely dive to 330' on trimix? Because of the narcosis? There's a lot more to deep diving than narcosis and if the diver doesn't realize that, I question if he should even be in the water.

Granted, but certainly all else being equal less narced > more narced.

Giving a diver an advanced trimix card good to 330' when the deepest the diver has been before certification is 180' (twice in his life, both with an Instructor? Beam me up Scotty....

Absolutely. That's extremely weird. I don't know what agency does, that, but I'll take your word that at least one does.

In any case, the point I was trying to make was one of personal responsibility. At this level, most divers recognize that, aside from allowing access to certain gases, cards aren't worth much more than the plastic they're printed on. Someone who is going to go to 180 twice with an instructor and then hop down to 330 is someone who would likely do it on air.

I don't know about canada, but here in the states the notion of personal responsibility is rapidly going by the wayside.

The agencies I have plastic from introduce helium fairly early, but restrict access to hypoxic gases (or rather explicitly state which gases the diver is 'qualified' for). Could I go get some 21/35 and ride it to 200 feet? Yah. Will I? No.

Exactly, and as DCBC aluded to, I wouldn't let someone drive a race car on a track if they hadn't already driven fast in a street legal car.

Sure, but on the same subject, I wouldn't prevent drivers from using seatbelts and airbags because the thought that they are better insulated may encourage them to drive more recklessly.

 

[Rainer]

Dealing with narcosis and having to problem solve in emergent conditions makes a better prepared diver for deeper dives. I have no doubt of this.

Nor do I have ANY doubt that you're completely wrong.

Hitting the roads drunk doesn't make you a better sober driver. It just puts you at increased risk.

Everyone here is in agreement that all divers should gain lots of experience before going deep. You keep going on about new divers getting trimix certs. It's a red herring. Who here is defending that? No one. Lots of people just fundamentally disagree with your statement that they should get deep air experience before adding helium.