An age-old question: ways to 60m.

[Kay Dee]

So you’re saying you failed to plan far enough ahead. You can get a T of He anywhere in the world. It might just be more work than you want to put in.

Nice try, but no cigar. No, I am saying the prospective operators gave such short notice that even if I had wanted to spend a shitload of bucks there was no helium available. I got the call, I took / did the job, on relatively short notice. Besides, given that I would have been the only one using it there was no need for helium at that time* given the calm warm water, great vis and max depth around 60m / 200ft.

*At the time the soon to be operators, very good divers that were, had no certs above AOW and I wasn't about to take them from that through trimix from the get go. Let them get some 'experience' with the new kit and procedures and came back six months or so later, IIRC, with Tom Mount when there was helium available to do their gas course.

And as for your "you can get T of helium anywhere in the world". BS on that! (Then also see my next post and what @old frogman said.)

 

[Kay Dee]

Then you have the logistic problem of making trimix blends on site.

Bingo!

 

[old frogman]

Not really on topic but while you are here...

Is there a theoretical way to train for higher gas densities similar to what climbers do for high altitude training? Is there some sort of Sherpa physiology equivalent for higher gas densities?
How about narcosis? Can the effect of high partial pressure Nitrogen on the nervous system be mitigated with training/drugs/pysiology?

 

[old frogman]

Narcosis cannot be mitigated in the sense of preventing it. It does occur. Military divers generally apply the following techniques to maximise function in deep air diving.

From a physical perspective, stay well rested and hydrated before the dive. Avoid alcohol, drugs or medications at least 8 hrs before dive. Begin dive in a calm and relaxed state (military use diver tenders who are persons designated to dress and assist the diver into and out of the water). Also, if you are physically fit, it reduces exertion.

From equipment perspective, use high performance regulators (balanced 1st and 2nd stage). Ensure they are serviceable. Check functionality prior to dive. Make sure gas is turned on prior to water entry. Use equipment procedural checklists and well-rehearsed predive checks

From dive execution perspective, do not overexert yourself, breathe deeply (to reduce CO2 accumulation in tissues), follow dive plan, use a shotline to descend and ascend (this avoids spatial disorientation which may occur in reduced visibility and may lead to anxiety). Anxiety can accentuate the narcosis effect. CO2 accumulation in tissues will facilitate the narcosis effect.

Important - Perform frequent buddy checks and monitor each other's behaviour.

Have emergency procedures well-rehearsed prior to dive.

Acclimatisation to the narcosis effects is achieved by increasing depth gradually on successive dives e.g. 5 metre increments, monitoring behaviour. Immediately do a partial ascent e.g 5 to10 metres or more if feeling drowsy or experience visual disturbances or anxiety.

Plan the dive and dive the plan. Do not deviate into situations which may create risk.

If diving in a group, appoint a leader for the dive team and a leader for surface support and supervision.

 

[Nick_Radov]

Not really on topic but while you are here...

Is there a theoretical way to train for higher gas densities similar to what climbers do for high altitude training? Is there some sort of Sherpa physiology equivalent for higher gas densities?

Theoretically higher levels of aerobic fitness ought to help by strengthening respiratory muscles and this increasing ventilatory capacity. Some of the lung training exercises used by musicians have a similar effect. Apnea sets used by swimmers and freedivers build some tolerance for hypercapnia, at least psychologically.
But that's all mostly theoretical. There's no evidence that any exercises can make deep air safe.

How about narcosis? Can the effect of high partial pressure Nitrogen on the nervous system be mitigated with training/drugs/pysiology?

Probably not. There is likely some small variation in individual physiology but this has never been quantified in an accurate, repeatable way. As for drugs, there are reasons to suspect that certain stimulants such as epinephrine or amphetamines might counteract some of the effects of narcosis, but those are obviously contraindicated in diving.

 

[leadduck]

GUE had training courses for ocean diving from the start. Jarrod Jablonski founded GUE partly because the idiots running some other "technical" training agencies thought that taking students to 190 ft / 57 m was an acceptable practice.

Twenty-five Years in the Pursuit of Excellence – The Evolution and Future of GUE

Founder and president Jarrod Jablonski describes his more than a quarter of a century long quest to promote excellence in technical diving.

indepthmag.com

That doesn't contradict what I wrote; the origins of GUE lie in the WKPP, and many of their standards and procedures are obviously aimed at safe cave diving in teams (and then spawn criticism by people who find them unnecessary in open water ocean dives). Deep air for example is more dangerous in caves than in open water.

 

[Blackcrusader]

Clearly, you've not dived very many places.

Of course he hasn't as so many places do not have Helium available.

 

[leadduck]

Yeah, right. You are most likely not going to know about it or discern that you are under the influence.

You missed my next sentence: "Not very reliable in practice, but at least there's a chance."
I think if you're narced, your buddies will notice it before you do. When your brain slows down, how will it notice that it got slower, that your response time got longer, your situational awareness is weaker? There's a big difference between not being impaired, and not feeling impaired, causing the self-deception.

 

[Kay Dee]

GUE had training courses for ocean diving from the start. Jarrod Jablonski founded GUE partly because the idiots running some other "technical" training agencies thought that taking students to 190 ft / 57 m was an acceptable practice.

Twenty-five Years in the Pursuit of Excellence – The Evolution and Future of GUE

Founder and president Jarrod Jablonski describes his more than a quarter of a century long quest to promote excellence in technical diving.

indepthmag.com

Nick, with all due respect, you would not be qualified to even fill some of those 'idiots' tanks.

And not just taking students to 190 / 57, as if the truth be known (as they say) but to 300 / 90 (Hal Watts's and his instructors) which even I think is a bit lot much But by the same token they never had a serious accident (any accident?) on any of their dives to that depth with students, or none that I am aware of, and I knew Hall and some of his instructors well enough. However, certainly not for me (300 / 90) on air, as that, in my opinion, is pushing things to far.

 

[iliketopetsharks]

GUE had training courses for ocean diving from the start. Jarrod Jablonski founded GUE partly because the idiots running some other "technical" training agencies thought that taking students to 190 ft / 57 m was an acceptable practice.

Twenty-five Years in the Pursuit of Excellence – The Evolution and Future of GUE

Founder and president Jarrod Jablonski describes his more than a quarter of a century long quest to promote excellence in technical diving.

indepthmag.com

Nice article, thanks for posting the link!

I was informed that he considered it a violation of standards not to teach air to a depth of at least 57 m/190 ft. This same individual told me that I had to stop using MOD bottle markings and fall in line with the other practices endorsed by his agency.

Yikes! Those really were different times...