First Dive Trip Without Instructor - Need to Rent Gear & Help Planning

[CavernFrog]

I was pointing out that at the depths you will find at that site, you will have no concerns about oxygen toxicity no matter how long you dive, so that safety issue is off the table. That does not mean, however, that you get to ignore NDLs.

Which is exactly why I responded with the NDL for EANx32. The wording of your post "all day" made it sound like you thought you could ignore NDLs at recreational depths with EANx32.

What you apparently meant by "all day" was not literally "all day" but you meant only that I would not hit a narcosis depth with EANx32 at Morrison Springs. OK, I get that you meant "all day" figuratively rather than literally and understand your point that there is nowhere beyond the MOD for EANx32 at Morrison Springs.

 

[Tecomah]

Narcosis =/= cns

 

[WetRocks]

What you apparently meant by "all day" was not literally "all day" but you meant only that I would not hit a narcosis depth with EANx32 at Morrison Springs. OK...

narcosis ≠ MOD

Seriously, not being snarky, I suggest you re-read through your nitrox materials or find alternate educational materials (or a mentor) and then come back and discuss this particular topic.

When is your upcoming trip? HIGHLY recommend stopping by Edd's and let us know, someone one can likely come out and meet you and have a chat about all of this and gear etc on your way to Destin.

 

[DogDiver]

I apologize up front. With the OP asking these multiple questions, it’s obvious he does not have a grasp on the very basics of over head environment diving. Please get more training before you and your buddy become a statistic. Again. Sorry.

 

[boulderjohn]

What you apparently meant by "all day" was not literally "all day" but you meant only that I would not hit a narcosis depth with EANx32 at Morrison Springs.

No. My post had absolutely 100% nothing to do with narcosis. It was all about oxygen toxicity, in both its CNS and pulmonary forms. What I meant is that you could do as many dives within NDL and at or below 1.4 PPO2 as you could fit into a day and not have any problem with with either form of toxicity. That is why they don't even mention pulmonary oxygen toxicity in recreational nitrox classes any more--it ain't gonna happen.

 

[tbone1004]

What you apparently meant by "all day" was not literally "all day" but you meant only that I would not hit a narcosis depth with EANx32 at Morrison Springs. OK, I get that you meant "all day" figuratively rather than literally and understand your point that there is nowhere beyond the MOD for EANx32 at Morrison Springs.

on top of what @boulderjohn said above, narcosis tolerance is VERY personal and there are an infinite amount of variables that contribute. Personal tolerance to narcotic gas is one, some people just don't get narc'd as easily. Ambient light, work load, hydration levels, etc etc all contribute to narcosis. I've been narc'd in a cave at 90ft on EAN32, I've also been to 150ft on air on a reef and was clear as a bell. There isn't a magical depth limit where people encounter narcosis. We accept that 4ata is generally where it will start to come on so in trimix we try to limit our combined ppO2 and ppN2 to 4.0 and fill the balance with He for narcosis management and gas density, but it doesn't mean that it's a "magic number".

More to the point, since O2 is narcotic, nitrox doesn't do anything for narcosis management

 

[boulderjohn]

More to the point, since O2 is narcotic, nitrox doesn't do anything for narcosis management

There was a study released in the last year that indicates that there might be some benefit to using nitrox in terms of narcosis, but what tbone1004 wrote is the traditionally accepted viewpoint.

 

[RyanT]

Personal tolerance to narcotic gas is one, some people just don't get narc'd as easily. Ambient light, work load, hydration levels, etc etc all contribute to narcosis. I've been narc'd in a cave at 90ft on EAN32, I've also been to 150ft on air on a reef and was clear as a bell

+1. And as tbone suggested, quite variable within individuals. I've been noticeably narced as shallow as 110' and much clearer on deeper dives. Cold and dark appear to make it worse, but in my experience, pre-dive stress can also increase narcosis unexpectedly.

 

[tbone1004]

There was a study released in the last year that indicates that there might be some benefit to using nitrox in terms of narcosis, but what tbone1004 wrote is the traditionally accepted viewpoint.

linky link? I heard about it, but haven't read the full study. I can say that I haven't noticed any benefit despite doing a lot of identical dives on air and nitrox. Curious to see what they did to demonstrate that and how they brought the narc on. I do know that I've gone quite deep in a chamber on air and my narc in the chamber was very different than the one I get in the water.... I get dark narc'd in the water, not fun.

 

[tursiops]

Although the OP is clearly confused about narcosis (a problem from too much nitrogen partial pressure, i.e. depth-related) versus CNS oxygen toxicity (a problem from too much oxygen partial pressure, i.e. depth-related), he is wrong to say that pulmonary oxygen toxicity (a problem from too long an exposure to oxygen at moderate partial pressures, i.e. time-related) is not in the PADI course. There is clearly a section on that in the student manual and in the instructor manual. The section, of course, says it is not likely a problem for recreational; diving. But it is clearly mentioned.