An age-old question: ways to 60m.

[old frogman]

1.6 was the cut off, oxygen toxicity was the real problem not narcosis when working. When we done a survey on the Spectator wreck in 83m we deemed it impossible ( for us) to salvage the copper ingots which littered the bottom.

Interesting, was the oxygen giving you pre-convulsion symptoms as in visual disturbances, ear ringing, muscle twitching etc? Or were they symptoms akin to narcosis as in difficulty concentrating on tasks?

I have heard that at above 1.4 BAR oxygen can be narcotic as opposed to toxic. Hypothesis at this stage.

Conversely, it is known that at 1.4 it can be toxic if breathed for long periods in association with exertion as per combat swimming on O2 rebreathers.

 

[Wibble]

There’s at least 30 wrecks north and northwest of Malin head in the 60m range that have all been dived on air at one time or another. It suits the charter boats to run groups of CCR divers but you’re mistaken if you believe private individuals are not diving on air. We dived the Tory and Malin wrecks on air and heliair out to 80m

Absolutely. I raise my hat to our forebears for doing the dives we all dream about (and on wrecks that were 40 years younger than today)

However with today’s technology and training, very few people would choose deep air over CCR+trimix. Not least for the runtimes, clear head and the ability to do multiple 2h+ dives in a week (7 days for us this week).

 

[Celt]

Absolutely. I raise my hat to our forebears for doing the dives we all dream about (and on wrecks that were 40 years younger than today)

However with today’s technology and training, very few people would choose deep air over CCR+trimix. Not least for the runtimes, clear head and the ability to do multiple 2h+ dives in a week (7 days for us this week).

Absolutely. I raise my hat to our forebears for doing the dives we all dream about (and on wrecks that were 40 years younger than today)

However with today’s technology and training, very few people would choose deep air over CCR+trimix. Not least for the runtimes, clear head and the ability to do multiple 2h+ dives in a week (7 days for us this

Agree 99% of the people and friends are diving CCR today but sightseeing in 60m on air by trained and experienced divers is not the death sentence some like to portray it for whatever agenda they have. The diving industry in Ireland are delighted to see sport diving advanced to CCR the more the merrier, there are more people visiting deep wrecks today than ever before because of rebreathers.

 

[Celt]

Interesting, was the oxygen giving you pre-convulsion symptoms as in visual disturbances, ear ringing, muscle twitching etc? Or were they symptoms akin to narcosis as in difficulty concentrating on tasks?

I have heard that at above 1.4 BAR oxygen can be narcotic as opposed to toxic. Hypothesis at this stage.

Conversely, it is known that at 1.4 it can be toxic if breathed for long periods in association with exertion as per combat swimming on O2 rebreathers.

The problem is identifying the symptoms, loss of peripheral vision is a very common effect of narcosis, BUT it is also one of the first signs of CNS O2 toxicity

 

[Wibble]

Interesting, was the oxygen giving you pre-convulsion symptoms as in visual disturbances, ear ringing, muscle twitching etc? Or were they symptoms akin to narcosis as in difficulty concentrating on tasks?

I have heard that at above 1.4 BAR oxygen can be narcotic as opposed to toxic. Hypothesis at this stage.

Conversely, it is known that at 1.4 it can be toxic if breathed for long periods in association with exertion as per combat swimming on O2 rebreathers.

Oxygen and nitrogen are equally narcotic, hence diving with 32% nitrox isn’t considered to be less narcotic than air. Nitrox does of course reduce the amount of inert gas ongassing as oxygen is metabolised, therefore significantly reduces the decompression obligation (e.g. 32% at 30m/100ft give about 30 mins NDL whereas air gives about 20 mins NDL)

To reduce narcosis you need to substitute nitrogen for helium, i.e. trimix. Best done with a rebreather.

 

[flymolo]

So who died and made you the spokes person for everyone on here? Maybe what I said doesnt apply to you / yours, so thats about the best you can claim, not "no one thinks that".

I also agree that no one thinks that

 

[Kay Dee]

I found an article he wrote in 1991 for AquaCorps to be quite informative informative.

Linked and another quote:The gravity of that error [being so narced that I didn't know the way to safety] ended my misdirected, ego-driven deep dives on compressed air, which, up until that time, had seemed so very important. From that experience, along with a few other not-quite-so-close calls, I began to reassess the reasons that I and others had used to justify a deep dive on air. -- Wes Skiles

Interesting you should post that. So it seems your getting your Wes iinfo from online sources / magazines?

Well , just to clarify a little re my understanding of Wes’s statement/s that you inserted into the ‘discussion’ here and where it / he came from / was coming from. Now I know there are people on here that knew Wes much better than I did, so maybe they know something else / have a different understanding, but although Wes had done his share of deep air dives, it was, again my, understanding from talking (and diving) with him that he was unduly(?) affected by narcosis (no shame in that) and hence did not like deep air dives (which was certainly his prerogative.) And he had lost his share of friends to deep air in cave dives too, which certainly did not enamor him to / turned him off the deep air ‘practice’ also. Anyway, lets not let this devolve into a discussion about Wes, but you did bring it up, and are trying to use 'him' to support your postion. May I suggest we let the (fond memories of the) man rest in peace, and take another tack, please?

And, for the record, I will be the first to admit that air has no place deep in caves, IMO anyway, nor deep wreck penetration either, again IMO, and I would certainly speak out against such ‘practices’ if asked by a prospective ‘adventurer’. But I ain't going around preaching that gospel to one and all, nor recommending it (air) either.

But if you asked me what is the gas of choice for ‘deep diving’ (now there is a very subjective term*) I’d always say, again, use gas!

*One should be very aware that when some of the 'old timers' used the term 'deep air' they were talking about dives on air deeper, some times considerably deeper, than 60m / 200ft, and which is not my 'definition' of 'deep air' in any context that I use those two words in. Just saying.

 

[Kay Dee]

JFTR, the Dalai Lama did not say that

OK @chillyinCanada I see you've been leaving likes for various post so your still here and with ample time now to come up with whatever you have that makes you say your above and answer my question about same, which was "And you know this, how?" So? (As I am genuinely interested in your response.)

Must say, I didnt expect you to be one of those folks, like some on here, that when you ask them a direct question to back up what they said / their stance....... they.......... dissapear, or go quiet.

 

[inquis]

So it seems your getting your Wes iinfo from online sources / magazines?

Correct, I did not know him, but I hold him in very high regard, as do many. However his story (in the pdf I linked) about his buddy passing out while just swimming along is plain sobering. The fact they were in an overhead environment is immaterial to that. As is the increased narcosis due to increased effort.

I think much of this discussion is due to people talking past each other. It's objectively "safer" -- a relative term -- to dive OC trimix at 60m. It may be "safe enough" -- an absolute and personal assessment -- for *you* to dive air to 60m on a reef. The issue is that being impaired may cloud your assessment of not being impaired. It's also not obvious whether "safe enough" is for the "fair-weather scenario" without due consideration to the SHTF scenario. Again, that's going to be a personal call.

My goal was simply to relate an account from someone for which deep-air was supposedly safe enough, but upon reflection of their experiences, realized that other factors were blurring the line *for them*. Potentially thought provoking for anyone reading this thread.

 

[chillyinCanada]

OK @chillyinCanada I see you've been leaving likes for various post so your still here and with ample time now to come up with whatever you have that makes you say your above and answer my question about same, which was "And you know this, how?" So? (As I am genuinely interested in your response.)

Must say, I didnt expect you to be one of those folks, like some on here, that when you ask them a direct question to back up what they said / their stance....... they.......... dissapear, or go quiet.

It's not on topic and you should be able to Google as easily as did I. The unlikelihood that the Dalai Lama said such a thing made it easy to find support that indeed, he did not. But here you go, and let this be an end to it:

Dalai Lama Instructions for Life | Snopes.com Dalai Lama Instructions for Life