How deep to you dive on air diluent?

mempilot · 19th January 2008, 02:37

Aside from narcosis, I agree with those that limit the depth based on achieving an acceptable PO2 on DIL flush. That being said, my LDS banks 21/35. So guess what? I use mix on all dives. A Rebreather fill card cost me $5 a bottle. An air fill wouldn't be much cheaper since the labor is the same and the minute amount of He is negligible.

The only consideration I use then is DIL flush PO2 limit based on my desired setpoint. Below 170 fsw, I would start dropping the mix to the next easily attainable gas, 18/45, then 10/50.

PeteS · 19th January 2008, 08:08

I used to dive on CCR Tmx all the time. Then I went and did Mod 3 in G Cayman. They said I needed to go deep on air dil.... So, there I was at 55m, narked out of my little tree thinking WTF am I doing this for...... Never again, He is your friend.

Mdemon · 19th January 2008, 08:36

Quote: (Originally Posted by Mark Chase)

Because there are times when Trimix is not available.

When i dived the canyon they wouldn't give me trimix because i wasn't Mod 3 despite the fact i am TDI Mix on OC. Not a good excuse but its the truth.

When we did the Brothers gig there was no trimix available on the livaboard so we did 50-60m on air.

Obviously if mix was available we would have used it on a CCR as even at red sea costing its cheep.

I thought the question was how deep would you be willing to go on air?

When I have access to mix I use it all the time. I did a 25m dive last Saturday on 18/45.

ATB

Mark

Same as that.

Started on mix, did MOD 1 on air then immediately back to mix.

Did an air dive about a year after MOD1 and was surprised to find I quite enjoyed it. When I went to the Red Sea and trimix wasn't available, I felt very comfortable on air. Then I did some deep ones and enjoyed the "challenge" of it and the physiological "buzz". I did some filming at 76m at the Canyon on air which was about as deep as the "buzz" felt safe.

There is also case for saying that a little nitrogen fix calms you down. I've been on some dark UK dives which felt a lot more enjoyable once the nitrogen kicked in at depth (on mix).

bletso · 19th January 2008, 12:59

As a rule usually no deeper than 35 msw. Heck with a mccr, why not? Helium is my friend. It helps to have a large supply and use precious little of it on a dive.

Dale

mempilot · 19th January 2008, 14:58

Quote: (Originally Posted by Mdemon)

...Then I did some deep ones and enjoyed the "challenge" of it and the physiological "buzz". I did some filming at 76m at the Canyon on air which was about as deep as the "buzz" felt safe.

There is also case for saying that a little nitrogen fix calms you down. I've been on some dark UK dives which felt a lot more enjoyable once the nitrogen kicked in at depth (on mix).

Dude,

Alchohol will calm the nerves too. So use some mix and belt back some shots before you dive. Whatever gets you through the dive, I guess??

anton610 · 19th January 2008, 15:34

Hello!

A good friend of mine dived with his EVO 70m with air duilent in freshwater

He showed me the Logfile...

i don't belived that, but now i think he's a little bit crazy!

regards anton

ps.: I think he was only one minute at 70 m.

mempilot · 19th January 2008, 21:58

Thanks everyone! Spanner on order and documents in hand.

Eric

PS. I'll try not to kill myself with the complexity!

**Gill Envy** · 19th January 2008, 22:13

Thanks everyone for all the feedback! Open to any and all additional comments but am particularly interested to hear from those who dive deep without HE. It sounds pretty unanimous that few folks venture deeper than 165 on air dilluent except for short touch downs and even that is sketchy and ill advised. Are there folks out there that go deeper for extended periods who don't use He? if so how do you deal with the need to be able to flush to lower po2...hypoxic dilluent/BO stages?

Mark C. I'm curious what your profile was like to 65m on air CCR and if you took extra precautions for being able to lower the po2.

I know there are folks out there that have inhibitions about He and am curious to hear more from them.

Also interested if the folks from the mCCR camp go deeper also on air dilluent and how they found maintaining po2 with the added narcosis.

My guess is that if I want to venture deeper i'll just have to get over my aversion to the added complexity of He. this discussion is helping me to warm up to that idea.

thanks again for all the input!

Again, i'm not planning on venturing deeper without further instruction so don't worry about such general discussions inadvertently encouraging me to do something stupid.

Gilles · 20th January 2008, 01:16

Quote: (Originally Posted by Gill Envy)

... how do you deal with the need to be able to flush to lower po2...hypoxic dilluent/BO stages?

It depends what flexibility you built into your rig. I, for e.g. have ADV (= BOV too) access and switch-ability for both on and off board tanks. I so far like use the following priority of considerations in my dive planning (not exactly like how I was trained, and has developed as a result of experience + Rebreather World discussion).

1) Always have safe gas to B/O to
2) Minimal but adequate B/O volume to get to surface
3) Low PO2 flushing

Priorities 1 & 2 tends to compromise 3. I can argue a net result and plan that is safer for many if not most circumstances.

Nailer99 · 20th January 2008, 03:21

Quote: (Originally Posted by Gill Envy)

Thanks everyone for all the feedback! Open to any and all additional comments but am particularly interested to hear from those who dive deep without HE. It sounds pretty unanimous that few folks venture deeper than 165 on air dilluent except for short touch downs and even that is sketchy and ill advised. Are there folks out there that go deeper for extended periods who don't use He? if so how do you deal with the need to be able to flush to lower po2...hypoxic dilluent/BO stages?

Mark C. I'm curious what your profile was like to 65m on air CCR and if you took extra precautions for being able to lower the po2.

I know there are folks out there that have inhibitions about He and am curious to hear more from them.

Also interested if the folks from the mCCR camp go deeper also on air dilluent and how they found maintaining po2 with the added narcosis.

My guess is that if I want to venture deeper i'll just have to get over my aversion to the added complexity of He. this discussion is helping me to warm up to that idea.

thanks again for all the input!

Again, i'm not planning on venturing deeper without further instruction so don't worry about such general discussions inadvertently encouraging me to do something stupid.

I've done 200 fsw here in Puget Sound, on air, at night, in 10 foof of vis, on OC. Not a problem.

At this point, I can't see doing that on my COPIS- I'll be taking trimix with Mel this spring- you interested in doing the class with me?

19th January 2008, 02:37	#31 (permalink)
mempilot Eric Stadtmueller Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,448	Re: How deep to you dive on air diluent? Aside from narcosis, I agree with those that limit the depth based on achieving an acceptable PO2 on DIL flush. That being said, my LDS banks 21/35. So guess what? I use mix on all dives. A Rebreather fill card cost me $5 a bottle. An air fill wouldn't be much cheaper since the labor is the same and the minute amount of He is negligible. The only consideration I use then is DIL flush PO2 limit based on my desired setpoint. Below 170 fsw, I would start dropping the mix to the next easily attainable gas, 18/45, then 10/50. __________________ Eric Stadtmueller, otherwise known as, MEM "Da Pilot"
(Online)

19th January 2008, 08:08	#32 (permalink)
PeteS Consent Issued! Current Rebreather/s: Inspiration Classic Inspiration Vision Other Rebreather/s: Join Date: Jun 2005 Location: New Zealand Posts: 532	Re: How deep to you dive on air diluent? I used to dive on CCR Tmx all the time. Then I went and did Mod 3 in G Cayman. They said I needed to go deep on air dil.... So, there I was at 55m, narked out of my little tree thinking WTF am I doing this for...... Never again, He is your friend. __________________ Pete S. http://www.steggle.co.nz Every silver lining has a cloud
(Offline)

19th January 2008, 08:36	#33 (permalink)
Mdemon SiegeEngine II Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Inspiration Classic Home Build Join Date: Feb 2007 Location: SWUK Posts: 1,931	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Mark Chase) Because there are times when Trimix is not available. When i dived the canyon they wouldn't give me trimix because i wasn't Mod 3 despite the fact i am TDI Mix on OC. Not a good excuse but its the truth. When we did the Brothers gig there was no trimix available on the livaboard so we did 50-60m on air. Obviously if mix was available we would have used it on a CCR as even at red sea costing its cheep. I thought the question was how deep would you be willing to go on air? When I have access to mix I use it all the time. I did a 25m dive last Saturday on 18/45. ATB Mark Same as that. Started on mix, did MOD 1 on air then immediately back to mix. Did an air dive about a year after MOD1 and was surprised to find I quite enjoyed it. When I went to the Red Sea and trimix wasn't available, I felt very comfortable on air. Then I did some deep ones and enjoyed the "challenge" of it and the physiological "buzz". I did some filming at 76m at the Canyon on air which was about as deep as the "buzz" felt safe. There is also case for saying that a little nitrogen fix calms you down. I've been on some dark UK dives which felt a lot more enjoyable once the nitrogen kicked in at depth (on mix). __________________ www.southwestmafia.com "small minds talk about people, Average Minds Talk About Events, GREAT MINDS TALK ABOUT IDEAS!" The WRONG Attitude will get you killed. "Once the agenda-monkeys and perfect-worlders have moved on, perhaps we can do some diving?"
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19th January 2008, 12:59	#34 (permalink)
bletso An independent diver. Current Rebreather/s: Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: May 2006 Location: Louisville, KY, USA Posts: 256	Re: How deep to you dive on air diluent? As a rule usually no deeper than 35 msw. Heck with a mccr, why not? Helium is my friend. It helps to have a large supply and use precious little of it on a dive. Dale
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19th January 2008, 14:58	#35 (permalink)
mempilot Eric Stadtmueller Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,448	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Mdemon) ...Then I did some deep ones and enjoyed the "challenge" of it and the physiological "buzz". I did some filming at 76m at the Canyon on air which was about as deep as the "buzz" felt safe. There is also case for saying that a little nitrogen fix calms you down. I've been on some dark UK dives which felt a lot more enjoyable once the nitrogen kicked in at depth (on mix). Dude, Alchohol will calm the nerves too. So use some mix and belt back some shots before you dive. Whatever gets you through the dive, I guess?? __________________ Eric Stadtmueller, otherwise known as, MEM "Da Pilot"
(Online)

19th January 2008, 15:34	#36 (permalink)
anton610 toni the strange Current Rebreather/s: Evolution Other CCR Other Rebreather/s: Other CCR Join Date: May 2006 Location: austria Posts: 179	Re: How deep to you dive on air diluent? Hello! A good friend of mine dived with his EVO 70m with air duilent in freshwater He showed me the Logfile... i don't belived that, but now i think he's a little bit crazy! regards anton ps.: I think he was only one minute at 70 m. __________________ "Das Übel kommt nicht von der Technik, sondern von denen, die sie mißbrauchen." Jacques-Yves Cousteau (1910-1997)
(Online)

19th January 2008, 21:58	#37 (permalink)
mempilot Eric Stadtmueller Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,448	Re: How deep to you dive on air diluent? Thanks everyone! Spanner on order and documents in hand. Eric PS. I'll try not to kill myself with the complexity! __________________ Eric Stadtmueller, otherwise known as, MEM "Da Pilot"
(Online)

19th January 2008, 22:13	#38 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,326	Re: How deep to you dive on air diluent? Thanks everyone for all the feedback! Open to any and all additional comments but am particularly interested to hear from those who dive deep without HE. It sounds pretty unanimous that few folks venture deeper than 165 on air dilluent except for short touch downs and even that is sketchy and ill advised. Are there folks out there that go deeper for extended periods who don't use He? if so how do you deal with the need to be able to flush to lower po2...hypoxic dilluent/BO stages? Mark C. I'm curious what your profile was like to 65m on air CCR and if you took extra precautions for being able to lower the po2. I know there are folks out there that have inhibitions about He and am curious to hear more from them. Also interested if the folks from the mCCR camp go deeper also on air dilluent and how they found maintaining po2 with the added narcosis. My guess is that if I want to venture deeper i'll just have to get over my aversion to the added complexity of He. this discussion is helping me to warm up to that idea. thanks again for all the input! Again, i'm not planning on venturing deeper without further instruction so don't worry about such general discussions inadvertently encouraging me to do something stupid. __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 19th January 2008 at 22:50.
(Online)

20th January 2008, 01:16	#39 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 762	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Gill Envy) ... how do you deal with the need to be able to flush to lower po2...hypoxic dilluent/BO stages? It depends what flexibility you built into your rig. I, for e.g. have ADV (= BOV too) access and switch-ability for both on and off board tanks. I so far like use the following priority of considerations in my dive planning (not exactly like how I was trained, and has developed as a result of experience + Rebreather World discussion). 1) Always have safe gas to B/O to 2) Minimal but adequate B/O volume to get to surface 3) Low PO2 flushing Priorities 1 & 2 tends to compromise 3. I can argue a net result and plan that is safer for many if not most circumstances. __________________ Gilles http://www.dirrebreather.com Last edited by Gilles : 20th January 2008 at 01:20.
(Offline)

20th January 2008, 03:21	#40 (permalink)
Nailer99 Joshua Smith Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: Seattle, WA, USA Posts: 222	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Gill Envy) Thanks everyone for all the feedback! Open to any and all additional comments but am particularly interested to hear from those who dive deep without HE. It sounds pretty unanimous that few folks venture deeper than 165 on air dilluent except for short touch downs and even that is sketchy and ill advised. Are there folks out there that go deeper for extended periods who don't use He? if so how do you deal with the need to be able to flush to lower po2...hypoxic dilluent/BO stages? Mark C. I'm curious what your profile was like to 65m on air CCR and if you took extra precautions for being able to lower the po2. I know there are folks out there that have inhibitions about He and am curious to hear more from them. Also interested if the folks from the mCCR camp go deeper also on air dilluent and how they found maintaining po2 with the added narcosis. My guess is that if I want to venture deeper i'll just have to get over my aversion to the added complexity of He. this discussion is helping me to warm up to that idea. thanks again for all the input! Again, i'm not planning on venturing deeper without further instruction so don't worry about such general discussions inadvertently encouraging me to do something stupid. I've done 200 fsw here in Puget Sound, on air, at night, in 10 foof of vis, on OC. Not a problem. At this point, I can't see doing that on my COPIS- I'll be taking trimix with Mel this spring- you interested in doing the class with me?
(Online)

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