Exactly how deep is "Deep Air?"

[LiteHedded]

What? I don't understand your point. Where did that came from?
Since it's me you quoted there must be something in my post that you misunderstood, no?

yea you said that trimix requires some expensive gear. a deep dive on air would require the same gear. the gas would be cheaper but the rest is the same
maybe i misunderstood what you were driving at there....

 

[LiteHedded]

With air, you can do your deco on backgas. Lots of people have done that in the past, and lots still do it. So you don't need to carry any deco stage. With trimix (especially those with a lot of He that are standard gases for some agencies) you need to carry deco stage(s).

Diving without any deco stage is more streamlined, I believe we can agree on that.

On the other hand, I agree with you on that, if one dives deeper than 45 meters/150 feet AND has to carry deco stage(s) then he'd better use trimix as backgas. At which END is another matter of debate, though.

false.

 

[Diver0001]

Too many people look for a dramatic transformation (such as Cool Tech felt) to define the depth they get narced. Paranoia is the SAFEST response to narcosis, but in reality most of us just morph into having the cognitive abilities of a cow (bovine index)... and we are too stupid at that depth to realize it.

Strangely I didn't read it like that. I rememberd two things clearly from his post (does that mean I'm narced?)

1) when you dive deeper than 200ft without any planning or experience then weird sht happens and you really aren't in a position to deal with it

and

2) Cooltech is a lot fatter now then when he was 21.

The first part of that came off to me as one of those überdiver stories that people only tell at parties after they've had too much to drink and the second part has more to do with the mid life crisis of *every* man who is fatter than they were when they were 21 than it has to do with diving.

I have my own über diver story, although I don't feel über for telling it. It's a true story. I was an inexperienced diver (looking back) and descending along a wall with my buddy when we dropped down on a group diving in a big single-file line along the wall. they were at about 40 metres.

The last diver in the line was (I guess) not quite at the same depth as the others and swam straight into a huge ball of discarded monofiliment.

I saw it happen was wasn't sure at first what the problem was because he started just moving is arms around wildly and he looked like he was struggling. I looked at my buddy, he looked at me, we both looked at te diver in question.

Then the flailing around started getting serious and he started sinking along the wall. I don't know for sure how deep it is there, but I think it's over 100m deep. He was in .... teeerrrubble! Big trubble.

I looked at my buddy again, he looked at me and I put my head down and started after him as fast as I could swim. It was the beginning of our dive, as I said, and I don't think the guy knew we were there yet. The incident started at about 40m.

I kept chasing him until I caught up and then pinned him against the wall. That was the first moment when I stopped for a second and could feel the narcosis.....pppfffffff! bad.

I picked up my gauges to look at them, read them, thought "bugger!" and dropped them and promptly forgot what they said. I picked them up again and thought "BUGGER" and dropped them again and promptly forgot what they said.

The third time I didn't bother picking them up to read them because I could remember that I said "bugger" the last two times. I was holding the diver against the wall and I could see that he was hopelessly entangled in a big ball of discarded fishing line. I stared at him trying to figure out what to do when about then my buddy arrived signing FRANTICALLY to ascend. I looked at him but didn't really see him and he signed it again. like this:

UP UP UP UP . FUC .. UP UP UP!!!!

after him signing up about 10 times I thought.... that's a better plan than my plan (my plan was to do nothing) and I grabbed our guy and started pulling him up.

fast forward to the shallows because I really don't know how we got there... and we spent the rest of dive ... for as much air as we had at 10-5 metres.

when the air was up we surfaced and hoped for the best. Nobody had a computer (we didn't have computers back then), nobody got bent, the guy's buddy never surfaced to look for him and the dude STILL owes me a beer that I never got!

Ultimately that was one big custer fluck that happened to work out ok. It still gives me the heebiejeebies to think about it.

oh yeah... and after the dive my depth gauge, that IIRC, went to about 200ft, was pinned... I have no idea how deep we were.

R..

 

[AfterDark]

yea you said that trimix requires some expensive gear. a deep dive on air would require the same gear. the gas would be cheaper but the rest is the same
maybe i misunderstood what you were driving at there....

I was referring to rebreathers. If your going to dive deep on trimix then you'll be safer (gas lasts longer) and as such the need to carry extra bottles is reduced. IMO rebreathers are the way to go with trimix. Sorry my thought process caused me not to be as clear as I would have liked.

 

[Rhone Man]

The first part of that came off to me as one of those überdiver stories that people only tell at parties after they've had too much to drink and the second part has more to do with the mid life crisis of *every* man who is fatter than they were when they were 21 than it has to do with diving.

I have my own über diver story, although I don't feel über for telling it. It's a true story. I was an inexperienced diver (looking back) and descending along a wall with my buddy when we dropped down on a group diving in a big single-file line along the wall. they were at about 40 metres.

Actually these stories are adding considerably more interest to these threads than earlier deep air threads. I always teach my students (non-diving context here) that you learn more from mistakes than from successes, so I hope a few others are brave enough to post their stories. Stories where people end up in a particular creek but managed to get out again have a lot to teach us; we shouldn't need to wait till someone ends up on a slab and in a DAN fatality report to look at these sort of incidents.

 

[Walter]

I'm interested in answers based on your personal assessment of narcosis and the point where you feel it adversely affects your ability to safely manage it.

We are all narced every time we descend. It's merely a matter of degree. The deeper we go the worse we get. Most of us don't feel the effects until we get fairly deep. We are all adversely affected long before we feel it. I've noticed some folks start doing some pretty stupid things at relatively shallow depths while others seem to do pretty well when much deeper. Plan your dive, dive your plan is never as important as on deep dives. Except for emergencies, divers should not alter plans at depth on deep dives.

I rarely feel any effects of narcosis. I know that at 168 feet, I feel normal, but my judgement of size is not accurate. I shot a very large snapper at that depth, it shrank as I ascended. I know my face has felt numb at 175. At 175, I've heard things that weren't there. At 200, I don't care about my buddy. I still have the ability to recognize that the self centered attitude comes from narcosis and I watch out for my buddy anyway. I don't like how I feel when I'm deeper than 175.

 

[ianr33]

"Deep Air" for me is deeper than I feel comfortable diving,and that varies hugely with dive conditions.

In an overhead,around 100 feet.
Cold,dark,OW 130 feet
Perfect Caribbean conditions, maybe 200 on a good day

 

[LiteHedded]

Actually these stories are adding considerably more interest to these threads than earlier deep air threads. I always teach my students (non-diving context here) that you learn more from mistakes than from successes, so I hope a few others are brave enough to post their stories. Stories where people end up in a particular creek but managed to get out again have a lot to teach us; we shouldn't need to wait till someone ends up on a slab and in a DAN fatality report to look at these sort of incidents.

unfortunately we don't have to wait long for deep air fatalities. they happen quite frequently

 

[hg frogman]

false.

You are right (no irony intended). Trimix doesn't always require a stage for deco. It depends on the mix. I edited my previous post accordingly. Thanks for having made me think out of my usual (and limited) box.

 

[wedivebc]

I find it hard to put a fixed set of rules on any dive profile. There are always variables that affect how deep, how long, what equipment etc and anyone who make hard rules for every aspect of their diving are not getting the most benefit out of the options that are available. If I say I will never dive below 100ft without helium means I will probably never dive Bikini Atoll. If I say I will never dive sidemount means I will miss a lot of cave passages. I think we should all be prepared to make some contingencies based on the environment but for the sake of this poll I put 131-150 as a definition of deep air. I may still be inclined to dive deep air under some circumstances using that definition.