Deep Air Poll. Well, Someone Has To Put Their Head Over The Parapet...

[GrimSleeper]

I blame Ste Wart, since he suggested it in the current, never-ending deep-air thread.

Let's try (some hope) not to have this turn into the usual slanging match. It would be interesting to know how many people there are on the board who, IN OPEN WATER:
(a) have dived deep air and still do, either habitually or when Helium is difficult/impossible to obtain, believing that the risks inherent are acceptable to them
(b) have dived deep air and no longer will, believing that the risks inherent in narcosis are unacceptable to them, or
(c) have been trained that an END greater than 30m/100' is an unacceptable risk, and rigorously follow that training.

As far as I'm concerned, all three positions are equally valid, but it would be interesting - and might reduce some of the mud-slinging - if everyone knew where everyone else was coming from.

My own position is that - with 20-30m/70-100' viz in 30C/86F water - the degree of narcosis I experience is acceptable (to me) down to 220' or so in open water. This is partly because (I believe, I have no objective evidence, feel free to flame) I have the experience and the skills to mitigate the risk, and partly because OC Trimix just isn't practicable here given that by the time I actually got Helium to the shop we'd be looking at a landed price in the region of US$0.24/litre (around US$6.80/cubic foot).

You'll notice there isn't an option for 'I have no experience whatsoever but think it would be cool to bounce 200 feet on an Al80'. There are so many wrongs in that even before you get to gas choices...

I wouldn't dream of doing deep air dives without doubles and two deco gasses, EAN50 and O2. I'm also going over into CCR so that we can start using Trimix here without going instantly bankrupt, mostly for overhead and so I can start exploring some of the deeper cleaning stations the sharks use, but there'll be little point not using He in the 150-200' range if it's costing me a few bucks rather than hundreds.

So, where's everyone else coming from?

 

[Centrals]

1. a or b: Depend on location.
2. c: wreck(below 40m and with penetration).

 

[GrimSleeper]

I was struggling to get the poll questions into 100 characters, and ended up failing to acknowledge that deep air + overhead = much more stupid. Thanks for pointing that out quite delicately, Centrals.

And if you're a or b, dependent on location, then I'd have you down as an a...

 

[Wookie]

I'm an easy narc, so 150" is quite deep enough for me.

 

[Dr. Lecter]

A: to ~240' assuming there's a good reason (i.e., wreck worth exploring) to be there, and I can have sufficient gas volume/redundancy, deco mixes, and tables/other plan redundancy available.

I look at viz, temp, and currents as complicating factors for a narcosis-affected dive, but don't see cold, dark, silty, current-swept wrecks as per se inappropriate candidates for deep air dives. These factors are environmental issues to be planned and executed around, like any other (fishing line/nets while narced, anyone?). In some cases my experience has been that a harsher dive environment can help with the distractions posed by narcosis in that it forces a kind of tunnel vision effect on me, whereas there's a better chance of the eye and mind wandering at 200' in peaceful, warm, sunny waters. I also think there's a similar benefit to the otherwise dangerous confines of a wreck ('There are the walls, there's my light, there's the line' all help remind me why I'm down there, exactly how dangerous the dive is, and that I need to pay attention to what I'm doing). As always, YMMV.

 

[DevonDiver]

I used to, but no longer will. Had been a regular thing to dive 230-265' on air, sometimes even night, solo and/or overhead (wreck). Nowadays, no more than ~180', depending on why.

 

[TMHeimer]

My deepest dive was 131' (but that was nitrox 28) but I've done a few to 100-120' on Air. I voted have not due to training as I assumed by deep you mean below 130'. I have not had noticible narcosis (though I know it always occurs to some degree). Aside from training reasons, what's the point with like 6 minutes bottom time, etc.? Hardly enough time to even pick up one shell...

 

[kaerius]

My deepest has been 134'(40.2m), and I'll defer going deeper until I get the training(or there's an emergency and I have to make a split second decision wether to break limits to aid someone), but probably not on air when I do so intentionally.

I'm not an easy narc, and the only narcosis symptom I've exhibited so far at those depths is rigid thinking(I can follow my training just fine, even do nitrox calculations in my head, my responses aren't really slowed down noticably, but I can't think outside the box).

 

[MaxBottomtime]

I used to go below 200' quite often. These days, I make one or two deep air divers per year to photograph wrecks for a project. The deepest I've been on air in the past dozen years is 182'. I didn't mind the dives before, but I'm using a smaller set of doubles and only one deco gas, so I limit my depth and bottom time now. I have used trimix, but the small number of deep dives I now make don't warrant the cost.

 

[Abdullah]

I dive air to 65 meters in warm water with low task loading. My overhead limit on air is 50 meters in warm water.