Deep Air - Here we go again....

[hg frogman]

Some "deep air training" is already part of the CMAS *** Diver course : skills, including rescue, have to be done at 40 meters, and part of the training consists in making sure that the students will experience and recognise narcosis (induced by adequate means, like fast descent without visual reference).

I fully agree that every diver has to know his (or her) limits very well. This is often done by going (little) step by (little) step. IT TAKES TIME.

I don't know if one more badge (like Deep Air Specialty) would help.

Good luck, and goodbye.

 

[Rhone Man]

The most vocal detractors of deep air also happen to be alums of the DIR philosophy as taught by GUE and UTD. Often times the verbiage of their detractions has a language tone that sounds very close to industry wide impositions. Something like, "this is the way I do it, this is the best way, this is the way everybody should do it. If you're not doing it this way you're doing it the wrong way and you are running serious risks against your life."

I thought that the unwritten rule of SB was that everyone knew this but no one was allowed to say it.

So in order to provide a concrete definition of deep air, I proposed that we define it by the max END stated in the training standards of these agencies, ie. 100 ft. Therefore Deep Air = anything below 100ft/33m.

Personally I'd prefer Deep Air = anything below 130ft/40m. I think the DIR philosophy is that below 100 ft a helium mix should be used, but virtually everybody else thinks that 130 ft is a more realistic limit. If you use 100 ft as the limit, it looks as though you are pushing for a "DIR vs everyone else" argument. And those always end badly.

 

[Sloth]

Personally I'd prefer Deep Air = anything below 130ft/40m. I think the DIR philosophy is that below 100 ft a helium mix should be used, but virtually everybody else thinks that 130 ft is a more realistic limit. If you use 100 ft as the limit, it looks as though you are pushing for a "DIR vs everyone else" argument. And those always end badly.

Talking out of my butt but I think you would find that a lot of GUE/UTD divers are ok with ENDs greater then 100 for easy, warm recreational dives. I think you start to see an adherence to the 100' END rule when you get to the more aggressive dives including ones that are in recreational limits. Since GUE/UTD trained divers are exposed to trimix so early on I think they (we) better appreciate the advantages for an END of 100' on more aggressive dives.

Everyone keeps bringing up recreational diving limits but this is the technical diving sub forum so most GUE/UTD divers will say; "yes, use END 100' for technical diving."

 

[Blackwood]

So in order to provide a concrete definition of deep air, I proposed that we define it by the max END stated in the training standards of these agencies, ie. 100 ft. Therefore Deep Air = anything below 100ft/33m.

Since most agencies don't specify END limits, I think it makes more sense to take gas out of the question and instead consider what the industry considers 'deep.'

If you are 'deep,' and you are breathing air, it's 'deep air.'

 

[Blackwood]

delete

 

[MXGratefulDiver]

Talking out of my butt but I think you would find that a lot of GUE/UTD divers are ok with ENDs greater then 100 for easy, warm recreational dives. I think you start to see an adherence to the 100' END rule when you get to the more aggressive dives including ones that are in recreational limits. Since GUE/UTD trained divers are exposed to trimix so early on I think they (we) better appreciate the advantages for an END of 100' on more aggressive dives.

Everyone keeps bringing up recreational diving limits but this is the technical diving sub forum so most GUE/UTD divers will say; "yes, use END 100' for technical diving."

I tend to agree with that ... tech diving introduces a whole different mindset, due to task loading and overhead considerations. There's quite a bit less margin for error than there is in recreational diving, and the consequences of error can be dramatically more serious ... and so a clear head becomes more important.

... Bob (Grateful Diver)

 

[Kevrumbo]

To Kevrumbo:
The first event leading to the bends you experienced is the MAJOR change you did in your dive plan while underwater (extending your bottom time from 30 to 50 minutes). How do you link this with Air diving ? Do you think that with Trimix you can do such changes underwater without any issue ? I mean, is that a practice that you would recommend to others ? Or were you so narced at depth that neither you nor you buddy realized that such a change was a BIG change ?
(No offense intended, I am just curious about some aspects of this mishap).<snip>

Because of the increased Nitrogen loading breathing Air mix instead of Trimix, you better be sure to complete the optimal amount of stop time on your deco profile. Thirty percent less deco time than the optimally prescribed amount turned out to be my limit, with no more margin left for error (i.e. left shoulder joint musculoskeletal strain during dive; rapid ascent; heavy excercise on surface post-dive etc). Just as important as the narcosis factor, IMHO, is making sure in getting rid of that extra N2 load on your tissues during deco & ascent --a clear head helps should you elect to make a change to your profile on-the-fly. . .

 

[holeup]

Hi guys, im kinda new to this forum, but im not new to commercial ot tech diving.
Im a welder/diver by trade and techi when time permits. Anyway saw the above thread about helium costs and as i guess you likely know helium is not a readily renewable gas, infact supplies are actually getting to low levels. Having said that now to my main question, haave any of you heard of or are aware of any progress in the use of hydrox? i know it sounds totally crazy but the theory behind it is the weight, the abundance and the the physical bennefits of using it in a breathing mix. IF it turns out to be as good as ive heard we might be closing in on the perfect mix. Just wondering if anyone here has heard much about it and where if anywhere its being tried out

 

[Sloth]

I think hydrox is highly unstable with oxygen levels above 4% (or there about) in high pressures like a scuba tank. I hear its great if you want to say do a dive to 1500 feet and dont wont to worry about HPNS. I dont think you will see many Hydrox labels on scuba tanks anytime soon

 

[Tortuga68]

Or is it also about bottom time?

It seems every time we have a deep air thread, many people just look at the depth (and gas obviously). Bottom time, conditions (water temp, viz, current etc) and 'work' should also come into it, but a lot of people just look at the depth & PPO2 and start freaking out YOU'RE GONNA DIE style

I posted a thread about doing a 74m air dive as part of the PSAI Narcosis Management course (16 dives in total, gradually deeper from 30m), and copped the expected bashing from the usual suspects

If you can do a 45 minute working dive at 66m on air (according to some tables), doing a supervised 74m training dive in warm water with good viz, no current, 10 minute BT (~4 in descent) and on a line (non-working dive) doesn't seem too crazy to me

/shrug

Sure, some people wouldn't do either dive, that's fine - each to their own