How deep to you dive on air diluent?

**Gill Envy** · 18th January 2008, 19:39

As I'm getting more confident in my style of diving and the set up of my rig, I am beginning to get that itch to go deeper on occasion. Since most of my diving is in slack dependent areas it's only an occasional jaunt i'm after in no or low current areas. The catch is that I have no desire to use Helium and it's not my intent to debate here about why that is. My training certification is to 140 FSW, 5 minutes of deco, but i'm now taking short dips to 150FSW/46MSW and getting more comfortable with the idea of racking up some more deco. I'm noticing some of the narcosis and post dive fatigue I used to get on OC after deeper dives, yet the call of HE is still not there and frankly I missed that relaxing mellow feeling I used to get. Going through Mod II to get certified to go deeper would be a natural move except I have no desire to use Helium. If there was an advanced MOD 1, for non-helium divers that want to go deeper, i'd take it. Since there is not, i'm wondering how deep folks go on air dilluent and if there are guidelines for deeper CCR diving on air diluent. Obviously, going much deeper would require staged hypoxic bail out, probably a good enough reason to get more training right there. I'm guessing i'm not the only one in this boat.

Anway, how deep are folks diving on air diluent and how deep do you think it's safe to go?
Do you have any training recommendations that would help me venture forth in a safe manner?

your input is much appreciated!

Mark Chase · 18th January 2008, 19:47

Quote: (Originally Posted by Gill Envy)

As I'm getting more confident in my style of diving and the set up of my rig, I am beginning to get that itch to go deeper on occasion. Since most of my diving is in slack dependent areas it's only an occasional jaunt i'm after in no or low current areas. The catch is that I have no desire to use Helium and it's not my intent to debate here about why that is. My training certification is to 140 FSW, 5 minutes of deco, but i'm now taking short dips to 150FSW/50MSW and getting more comfortable with the idea of racking up some more deco. I'm noticing some of the narcosis and post dive fatigue I used to get on OC after deeper dives, yet the call of HE is still not there and frankly I missed that relaxing mellow feeling I used to get. Going through Mod II to get certified to go deeper would be a natural move except I have no desire to use Helium. If there was an advanced MOD 1, for non-helium divers that want to go deeper, i'd take it. Since there is not, i'm wondering how deep folks go on air dilluent and if there are guidelines for deeper CCR diving on air diluent. Obviously, going much deeper would require staged hypoxic bail out, probably a good enough reason to get more training right there. I'm guessing i'm not the only one in this boat.

Anway, how deep are folks diving on air diluent and how deep do you think it's safe to go?
Do you have any training recommendations that would help me venture forth in a safe manner?

your input is much appreciated!

30 in the UK 60 in blue clear warm reefs.

Deepest CCR air dive 65m in Dahab The canyon near the Hutts. Easy dive.

ATB

Mark

Stephane · 18th January 2008, 19:52

Gilles,

It depends on the PpO2 you are planning to use. At 55m, with a PpO2 of 1.3, you will breathe air. If you go deeper with maintaining this PpO2, the gas willbe more and more narcotic due to PpN2 raising.
You will have the to use a higher PpO2.

akscubainst · 18th January 2008, 19:59

Quote: (Originally Posted by Gill Envy)

Anway, how deep are folks diving on air diluent and how deep do you think it's safe to go?
Do you have any training recommendations that would help me venture forth in a safe manner?

your input is much appreciated!

About 140' I've noticed myself being pretty narc'd on the Kiss at that depth more than I remember on OC.

Why wouldn't you want to go with HE?

Dave

jkaterenchuk · 18th January 2008, 20:07

You might want to look over the ANDI CCR program. Specifically, course TRD Level 3 - Technical Rebreather Diver Level 3. Link attached to the course standards.

Untitled Page

I just finished the course with Bruce Konefe in Thailand and its rated to 50MSW/164FSW and 30 Minutes of Deco only Air Diluent. I will be doing a detailed write up on the blow by blow for each dive on this course as well as a few others I took once I get a few spare hours. ANDI's program is indepth and ensures you are task loaded with valuable exercises in controlled conditions. It really starts to get you comfortable with many critical skills like SCR for extended periods.

Not sure if this fits the bill for what your are looking for but I thought I would mention it.

John

Abbo · 18th January 2008, 20:12

On OC, I was perfectly happy going to 57m on air, where the PO2 hits 1.4. I did that regularly and presumed I would be able to do the same on CC. The trouble, of course, is that even the best CCRs have WOB like the worst regulators. If I recall correctly, a really good reg is around 0.8J/litre, whereas my Meg does a slovernly 1.7 or so at 40m. No drama, I thought: I'm fit - what do I care about a few joules either way. Then I had an experience where I had a very strong current and needed to fin very hard against it - at depth. I was screaming for air but I felt like I couldn't breathe. My takeaway from that is that I should start using mix far shallower than I would on OC: everything I breathe has to pass through a tub of kitty litter, so it makes sense to breathe something thin and light - trimix.

Theoretically, in addition to WOB, there are problems related to narcosis as well. My understanding is that CO2 levels are higher on CC than OC even when the scrubber is working well. That's going to work in concert with the high PN2 to make you more narked. You have a lot more to think about on CC than the 'breathe in; breathe out' of OC. It makes a lot of sense to breathe the mix that gives you a clear head: you're rebreathing it, so it's much less of a cost issue.

The upshot: I would hesitate to dive much deeper than 40m on CC, and would do even that only in unchallenging conditions. A pussy? Perhaps, but a live pussy.

***Beanie*** · 18th January 2008, 20:33

I do all my diving on mix unless I borrow the GF dil tank.
Have been to 40m in UK on air didn't like it
Have been to 50m in the red sea on air was happy.

I tend to think that Tx is cheap so I use it.

**nigelh** · 18th January 2008, 20:43

Quote: (Originally Posted by Beanie)

Have been to 50m in the red sea on air was happy.

When I did that I was far too happy.

I won't make that mistake again.

Numpty diver · 18th January 2008, 20:52

which book/books did you use for your ccr trimix courses?
Any recomandations for trimix ccr books ?
Dean

***diverklondike*** · 18th January 2008, 20:54

I almost ALWAYS have some "He" in my dil... The only exception is shallow oyster or quarry diving... Less than 75ft ffw.

It's amazing how much more you remember etc with a bit of "He" in the mix even on 100ft dives.

Dive Safe...

Mark

18th January 2008, 19:39	#1 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,255	How deep to you dive on air diluent? As I'm getting more confident in my style of diving and the set up of my rig, I am beginning to get that itch to go deeper on occasion. Since most of my diving is in slack dependent areas it's only an occasional jaunt i'm after in no or low current areas. The catch is that I have no desire to use Helium and it's not my intent to debate here about why that is. My training certification is to 140 FSW, 5 minutes of deco, but i'm now taking short dips to 150FSW/46MSW and getting more comfortable with the idea of racking up some more deco. I'm noticing some of the narcosis and post dive fatigue I used to get on OC after deeper dives, yet the call of HE is still not there and frankly I missed that relaxing mellow feeling I used to get. Going through Mod II to get certified to go deeper would be a natural move except I have no desire to use Helium. If there was an advanced MOD 1, for non-helium divers that want to go deeper, i'd take it. Since there is not, i'm wondering how deep folks go on air dilluent and if there are guidelines for deeper CCR diving on air diluent. Obviously, going much deeper would require staged hypoxic bail out, probably a good enough reason to get more training right there. I'm guessing i'm not the only one in this boat. Anway, how deep are folks diving on air diluent and how deep do you think it's safe to go? Do you have any training recommendations that would help me venture forth in a safe manner? your input is much appreciated! __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 18th January 2008 at 21:10.
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18th January 2008, 19:47	#2 (permalink)
Mark Chase I go down for ages Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Jan 2005 Location: Kent Posts: 2,470	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Gill Envy) As I'm getting more confident in my style of diving and the set up of my rig, I am beginning to get that itch to go deeper on occasion. Since most of my diving is in slack dependent areas it's only an occasional jaunt i'm after in no or low current areas. The catch is that I have no desire to use Helium and it's not my intent to debate here about why that is. My training certification is to 140 FSW, 5 minutes of deco, but i'm now taking short dips to 150FSW/50MSW and getting more comfortable with the idea of racking up some more deco. I'm noticing some of the narcosis and post dive fatigue I used to get on OC after deeper dives, yet the call of HE is still not there and frankly I missed that relaxing mellow feeling I used to get. Going through Mod II to get certified to go deeper would be a natural move except I have no desire to use Helium. If there was an advanced MOD 1, for non-helium divers that want to go deeper, i'd take it. Since there is not, i'm wondering how deep folks go on air dilluent and if there are guidelines for deeper CCR diving on air diluent. Obviously, going much deeper would require staged hypoxic bail out, probably a good enough reason to get more training right there. I'm guessing i'm not the only one in this boat. Anway, how deep are folks diving on air diluent and how deep do you think it's safe to go? Do you have any training recommendations that would help me venture forth in a safe manner? your input is much appreciated! 30 in the UK 60 in blue clear warm reefs. Deepest CCR air dive 65m in Dahab The canyon near the Hutts. Easy dive. ATB Mark __________________ Is it supposed to make that noise ? I took my unit to the dive shop and demanded they bolt on every thing that would fit. Join my elite diving teem and get a Tshirt "Doing It Chasey"Hammerhead Eccr Advanced Diving System
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18th January 2008, 19:52	#3 (permalink)
Stephane Hey! Ho! Let's go! Current Rebreather/s: rEvo Other Rebreather/s: rEvo Join Date: Nov 2005 Location: Nantes - France Posts: 725	Re: How deep to you dive on air diluent? Gilles, It depends on the PpO2 you are planning to use. At 55m, with a PpO2 of 1.3, you will breathe air. If you go deeper with maintaining this PpO2, the gas willbe more and more narcotic due to PpN2 raising. You will have the to use a higher PpO2. __________________ Stéphane Hammer-rEvo powered!
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18th January 2008, 19:59	#4 (permalink)
akscubainst It's cold here! Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: May 2005 Location: Juneau, Alaska Posts: 62	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Gill Envy) Anway, how deep are folks diving on air diluent and how deep do you think it's safe to go? Do you have any training recommendations that would help me venture forth in a safe manner? your input is much appreciated! About 140' I've noticed myself being pretty narc'd on the Kiss at that depth more than I remember on OC. Why wouldn't you want to go with HE? Dave __________________ --------------------------------------- Dave Mitchell Classic KISS #200 Juneau, Alaska
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18th January 2008, 20:07	#5 (permalink)
jkaterenchuk . Current Rebreather/s: Inspiration Classic Megalodon Classic Kiss Other Rebreather/s: Join Date: May 2006 Location: Lititz, PA Posts: 652	Re: How deep to you dive on air diluent? You might want to look over the ANDI CCR program. Specifically, course TRD Level 3 - Technical Rebreather Diver Level 3. Link attached to the course standards. Untitled Page I just finished the course with Bruce Konefe in Thailand and its rated to 50MSW/164FSW and 30 Minutes of Deco only Air Diluent. I will be doing a detailed write up on the blow by blow for each dive on this course as well as a few others I took once I get a few spare hours. ANDI's program is indepth and ensures you are task loaded with valuable exercises in controlled conditions. It really starts to get you comfortable with many critical skills like SCR for extended periods. Not sure if this fits the bill for what your are looking for but I thought I would mention it. John
(Online)

18th January 2008, 20:12	#6 (permalink)
Abbo Going down on Meg Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Aug 2006 Location: Tokyo Posts: 389	Re: How deep to you dive on air diluent? On OC, I was perfectly happy going to 57m on air, where the PO2 hits 1.4. I did that regularly and presumed I would be able to do the same on CC. The trouble, of course, is that even the best CCRs have WOB like the worst regulators. If I recall correctly, a really good reg is around 0.8J/litre, whereas my Meg does a slovernly 1.7 or so at 40m. No drama, I thought: I'm fit - what do I care about a few joules either way. Then I had an experience where I had a very strong current and needed to fin very hard against it - at depth. I was screaming for air but I felt like I couldn't breathe. My takeaway from that is that I should start using mix far shallower than I would on OC: everything I breathe has to pass through a tub of kitty litter, so it makes sense to breathe something thin and light - trimix. Theoretically, in addition to WOB, there are problems related to narcosis as well. My understanding is that CO2 levels are higher on CC than OC even when the scrubber is working well. That's going to work in concert with the high PN2 to make you more narked. You have a lot more to think about on CC than the 'breathe in; breathe out' of OC. It makes a lot of sense to breathe the mix that gives you a clear head: you're rebreathing it, so it's much less of a cost issue. The upshot: I would hesitate to dive much deeper than 40m on CC, and would do even that only in unchallenging conditions. A pussy? Perhaps, but a live pussy. Last edited by Abbo : 18th January 2008 at 20:16.
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18th January 2008, 20:33	#7 (permalink)
*Beanie* Politeness officer Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,163	Re: How deep to you dive on air diluent? I do all my diving on mix unless I borrow the GF dil tank. Have been to 40m in UK on air didn't like it Have been to 50m in the red sea on air was happy. I tend to think that Tx is cheap so I use it. __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk www.divelife.co.uk
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18th January 2008, 20:43	#8 (permalink)
nigelh New Member Current Rebreather/s: Inspiration Vision Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Mar 2005 Location: Brighton, Sussex, UK Posts: 792	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Beanie) Have been to 50m in the red sea on air was happy. When I did that I was far too happy. I won't make that mistake again. __________________ nigelh
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18th January 2008, 20:52	#9 (permalink)
Numpty diver Custom Title Allowed! Current Rebreather/s: Other CCR Dolphin Ray Home Build Other Rebreather/s: Other CCR Dolphin Ray Home Build Join Date: Jul 2006 Location: Norway, Bergen Posts: 198	Re: How deep to you dive on air diluent? which book/books did you use for your ccr trimix courses? Any recomandations for trimix ccr books ? Dean
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18th January 2008, 20:54	#10 (permalink)
*diverklondike* Moderator Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Inspiration Classic Other CCR Join Date: Oct 2005 Location: Delaware, USA Posts: 1,462	Re: How deep to you dive on air diluent? I almost ALWAYS have some "He" in my dil... The only exception is shallow oyster or quarry diving... Less than 75ft ffw. It's amazing how much more you remember etc with a bit of "He" in the mix even on 100ft dives. Dive Safe... Mark
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