Future of OC trimix

[Alaskan Scuba Dude]

RAID Deco 40 would have allowed you the option of using Trimix; although, by your own definition you have reached your target depth of 150 feet using air after you were recently certified with TDI. So what is your problem? A dive to 160 feet would only require a small amount of Trimix since your Equivalent Narcotic Depth can be calculated from 150 feet.

 

[Wibble]

No additional dives needed for Helitrox when combined with AN/DP.

I will say it again. Asking a student who gets severely narked at 130ft to go to 150ft for training dives on air **because helium is not at available at all** is stupid and dangerous. Doing AN/DP open circuit on air would not be a good idea for me. Can’t help it that I’m unlucky with helium unavailable.

I'm actually saying that it's not necessary to dive as deep as 40m/130ft for ANDP.

The point of ANDP is to exceed the NDLs using accelerated decompression techniques. All of that is way more useful shallower than the limit of ~45m/150ft

In this time of helium shortages, someone's got to adjust the courses to what's actually available. If helium's too expensive or simply not available, then dive using nitrox but shallower.


Am really not sure why nobody else is saying this. All of the techniques for ANDP are perfectly applicable far shallower -- my dive tomorrow will be 30m/100ft and I'll be doing around 75mins on the bottom and 30ish mins of deco (whatever my computer says); runtime about 2 hours (unless it's completely crap).

 

[sea_ledford]

It’s a former open pit mine with roads and walls at various depths. A dive to 150 means the bottom at that point is about 150-160.

My point was that this insistence for AN/DP before going CCR is dangerous when helium isn’t available and students are narked bad even within recreational depths. I sure as hell won’t be doing ANY dives to 150 on air. If I can’t get helium, I won’t do them.

Awesome. I would consider that calling the dive beforehand. Excellent decision! You would get brownie points in my class and we would modify the plan as necessary to meet both requirements and expectations of the students. There isn't a requirement to dive to the maximum allowable depth for certification, although there might be that expectation from students. You could do most of AN/DP shallower than 100'. If your personal tolerances were to less than 130, it can be accomodated. But you are a bit of an outlier there. 10's of thousands of dives on air to 130 feet are conducted every year, very few people have debilitating results from that.

And I'm not a CCR instructor, but I'm pretty sure that Advanced Nitrox is a required part or pre req of any CCR class. It certainly was for my initial IANTD CCR course. Actually, I just checked the TDI standards, you only need TDI nitrox (ie not computer only nitrox) for the Air Dil CCR, but you would need both AN/DP for Air Dil deco CCR.

I think most of the people saying AN/DP should be taken first are considering the skills, not the depth, as being important. It's also nice to find out if you absolutely despise hovering in midwater for 20 or 30 minutes BEFORE you drop $15k on a CCR and associated training.

 

[Wibble]

RAID Deco 40 would have allowed you the option of using Trimix; although, by your own definition you have reached your target depth of 150 feet using air after you were recently certified with TDI. So what is your problem? A dive to 160 feet would only require a small amount of Trimix since your Equivalent Narcotic Depth can be calculated from 150 feet.

Few people would choose to dive to 45m/150ft on air unless you enjoy being off your face with narcosis. Fine for Jaques Cousteau, but beyond most people's narcosis limits.

I would, and have, done that and deeper on nitrox but don't enjoy it that much as you have to be extremely cautious and concentrate. It feels like 6 pints of Old Scrote pissed. Last time I had a conversation with a crab, didn't pull it though so obviously the old charm failed.

 

[sea_ledford]

Is ASD accurate on the RAID 40 course? Is a BOT cross referencing standards from a different website?? And are we just letting it run free on scuba board to see what happens? And has it been confirmed that its a BOT and not just a troll?

I mean it's very impressive technology and will be the downfall of the internet, so I'm in favor of the experiment, but shouldn't it be labeled or something, so people stop arguing with it?

 

[Wibble]

Ooops!

See, talking to crabs and now talking to bots... And this is at sea level.

 

[Marie13]

And I'm not a CCR instructor, but I'm pretty sure that Advanced Nitrox is a required part or pre req of any CCR class. It certainly was for my initial IANTD CCR course. Actually, I just checked the TDI standards, you only need TDI nitrox (ie not computer only nitrox) for the Air Dil CCR, but you would need both AN/DP for Air Dil deco CCR.

I'm looking at the TDI Air Dil Deco CCR standards. Read that *OR*. AN/DP is NOT required.

TDI Air Diluent CCR Decompression Procedures Diver -

www.tdisdi.com

• • Minimum age 18
  • Provide proof of 50 logged dives
  • Provide proof of TDI Advanced Nitrox Diver and Deco Procedures Diver or equivalent from agencies recognized by TDI
  • If the rebreather is a TDI approved sidemount rebreather, the student must hold the TDI Sidemount Diver certification or equivalent and provide proof of 10 logged sidemount dives

OR​

• • 
    
  • • Minimum age 18
    • TDI Air Diluent CCR Diver certified or equivalent
    • 30 hours on the CCR unit
    • Six months CCR diving experience

I know a number of people who had no OC tech experience. All done CCR. @Whitrzac himself has posted before that he's done ALL his tech stuff CCR.

 

[Marie13]

Awesome. I would consider that calling the dive beforehand. Excellent decision! You would get brownie points in my class and we would modify the plan as necessary to meet both requirements and expectations of the students. There isn't a requirement to dive to the maximum allowable depth for certification, although there might be that expectation from students. You could do most of AN/DP shallower than 100'. If your personal tolerances were to less than 130, it can be accomodated. But you are a bit of an outlier there. 10's of thousands of dives on air to 130 feet are conducted every year, very few people have debilitating results from that.

And I'm not a CCR instructor, but I'm pretty sure that Advanced Nitrox is a required part or pre req of any CCR class. It certainly was for my initial IANTD CCR course. Actually, I just checked the TDI standards, you only need TDI nitrox (ie not computer only nitrox) for the Air Dil CCR, but you would need both AN/DP for Air Dil deco CCR.

I think most of the people saying AN/DP should be taken first are considering the skills, not the depth, as being important. It's also nice to find out if you absolutely despise hovering in midwater for 20 or 30 minutes BEFORE you drop $15k on a CCR and associated training.

I'm not the only one here with significant narcosis issues. @formernuke is another. The only difference is he has helium available. I agree that the skills are important, but I can't actually believe an instructor would do dives shallower because a student gets narced. And isn't that sort of significant information a student should share BEFORE the class? My instructor, when told of my mush brain at 130, didn't suggest doing class shallower. Adding helium was recommended. But now there is no helium.

 

[Mr. Dooley]

RAID Deco 40 would have allowed you the option of using Trimix; although, by your own definition you have reached your target depth of 150 feet using air after you were recently certified with TDI. So what is your problem? A dive to 160 feet would only require a small amount of Trimix since your Equivalent Narcotic Depth can be calculated from 150 feet.

Correct, I'm now certified via TDI to conduct deco dives of up to 150' on air - my dives during my instruction never actually went that deep (129' max). That being said from a narcosis standpoint I'm unsure if diving to 150' on air is something I'll be doing or not. Deepest I've been is 134' so another sixteen feet is unlikely to make a world of difference - I felt fine but it's hard to say if was narced or not, and to what degree as the dive itself was easy and nothing unexpected came up. Part of the value of of trimix to me was being able to conduct deeper dives and be able to mitigate narcosis. I also have interest in exploring beyond 160' at some point.

Or maybe I'll find that personally, I seem to be OK on air at 150 - I'll someone put math problems on a slate and then give 'em a go on deeper dives to maybe get a better gauge.

 

[Alaskan Scuba Dude]

(1 - .15 He) x (48 meters+10) - 10 = 39.3 END
(1 - .15 He) x (158 feet + 33) - 33 = 129.6 END