How deep to you dive on air diluent?

Drmike · 20th January 2008, 05:31

Quote: (Originally Posted by lizardland)

Air dil is a bit like getting a Jaguar converted to run off chip fat.

lol

**Gill Envy** · 20th January 2008, 07:09

Quote: (Originally Posted by Nailer99)

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?

Nailer,
Now you've done it...you just had to go and invite me in on a class...the siren call is beginning to take hold

.

well we'll have to see how this unfolds. I'd definitely be up for a dive soon in any case. if you are interested, drop me a line.
g

Mark Chase · 20th January 2008, 11:08

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.

.

It wasn't really much of an issue, You breath down the PP02 as you descend past the 1.3 mark and the unit then kept me at 1.3 no problem. Obviously sucking in diluent would spike the PP02 a little but again i didn't find it an issue. PP02 would have been about 1.6 at max depth so the odd 0.3 was an additional PP of Nitrogen. End result I had an EAD of 69m

We functioned OK. I shot video of the whole thing and drew a map afterward to try and help Louise find the cave entrance we found. She was doing a study on the canyons in the area.

We didn't try anything too adventurous we just mosied along at the bottom of the canyon. We did go through a chimney on the ascent at around 50m but apart from that its was easy peasy in clear blue warm stuff. We just followed our VR3s for deco total dive time was 110mins

ATB

Mark

PSquared · 21st January 2008, 04:43

On OC I was a deep air freak regularly doing sub 55m on air, deepest being 102 (admittedly I was 12 years younger, 10kg lighter, a lot fitter and pretty stupid). Since switching to CCR there is absolutely NO reason to dive deep on air as a dil. I switched to machines to make my deep diving safer, not more dangerous.

At the risk of sounding like a reformed alcoholic (which I supose I could be likened to) - it's not worth it. Helium is cheap to use on the machine and the machine's drills when you hit the brown smelly stuff require a lot more task loading than on OC - IMHO a tox will hit you sooner because of this.

After a dive to 48 using air as dil recently, I've decided 40m tops using air as dil. If He or accurate analysing isn't available, I'll do the deeper stuff on air using OC - less complicated, less to go wrong and IN MY OPINION easier to manage when stoned.

***jradomski*** · 21st January 2008, 10:09

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/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!

As long as He is available I ALWAYS have it in my dil..

That being said I have multiple 70m+ dives on air dil in places like truk where He was unavailable..

When I first started diving deep (before trimix) and when I was ALOT younger I did multiple 100m dive on air ( Oc ) but usually the limit was 70-75m

Ant Slegg · 21st January 2008, 14:52

42m in British waters.
However I am trying to log enough hours so that I feel confident enough for trimix.
Why?
With a fixed ppO2 I really do notice the narcosis (i.e. set to ppO2 to 1.3bar) but go to depths were OC would raise the ppO2 and ppN2 together.
I'd like to switch entirely to a trimix based system for all diving. That would be very wasteful on shallower OC dives but so much less so with CCR that (other than availability) I am struggling with why anyone would use air on any dive.

Ben Field · 21st January 2008, 15:30

Quote: (Originally Posted by Ant Slegg)

I am struggling with why anyone would use air on any dive.

Because people are naturally pikeys

You buy a Rebreather that costs more than your car and are too tight to buy a Dil fill that costs less than a round?

Oh and the real reason (in the UK) is that unless you find a source of helium or premix its getting very difficult to buy

**PhilSiswick** · 21st January 2008, 16:24

Quote: (Originally Posted by Ben Field)

Because people are naturally pikeys

You buy a Rebreather that costs more than your car and are too tight to buy a Dil fill that costs less than a round?

Oh and the real reason (in the UK) is that unless you find a source of helium or premix its getting very difficult to buy

Just get a largish cylinder and bank it. It's working for me so far and it feels as if I live further from a source of He (or decent pressure O2) than most in the UK.

If I'm going somewhere where the skipper or a local shop can do mix, then I take my 'bank' cylinder with me and get it filled to the brim again. That means I always have some for diving in between such trips.

It's worked so far - no air diving for me since I did Mod 1 and costs have been much lower than I expected, even though I haven't been getting my mix and O2 from the cheapest locations.

Cheers,

**Gill Envy** · 21st January 2008, 17:38

for some folks cost may be an issue with He but it seems pretty negligible from what I can tell. I've got more 80's waiting to bank something. I transfill my own o2 and dilluent and buy sorb in bulk...the cost of consumables is probably less than a regular air fill per hour, negligable enough that it's hardly a factor in my choice of diving style, which is how I want it... makes pushing the envelope on gas and sorb calculations hardly a temptation. From what i'm hearing banking He or mix wouldn't add that much in the grand scheme of things, if I go in that direction I'm guessing i'll shift to using it nearly all the time.

Hesitations around adding more complexity/dangers and going overboard for the diving I do are all reasons for making a solid assessment of my needs. For me the main reason is probably a lack of familiarity, a kind of superstitious fear that I once had about rebreathers but eventually got over. I'm guessing that once/if I make the transition that there will be no looking back accept to laugh at my hesitation. I guess you could call it a mental block. Difficulty in finding it in remote areas is one more reason, there will be times when it's not available and I will need to know what limits I'm comfortable with on air.

this thread is an attempt to see where others draw the bottom line for diving on air diluent, one of the ways i'm assessing how I need to limit my diving or where I need to make the transition to trimix. Luckily I have no qualms about taking my time to figure this out.

again, thanks for the feedback folks, keep it coming!

g

Quote: (Originally Posted by Ben Field)

Because people are naturally pikeys

You buy a Rebreather that costs more than your car and are too tight to buy a Dil fill that costs less than a round?

Oh and the real reason (in the UK) is that unless you find a source of helium or premix its getting very difficult to buy

Nailer99 · 21st January 2008, 18:39

Most of the CCR divers I dive with simply fill their dil with something like 15/50 as a matter of course- that way they're good to go for any profile they're likely to do around here. I'll let you know when the trimix class dates are after I talk with Mel, but, yeah- soon, in the next couple months...

20th January 2008, 05:31	#41 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,165	Re: How deep to you dive on air diluent? Quote: (Originally Posted by lizardland) Air dil is a bit like getting a Jaguar converted to run off chip fat. lol __________________ Cave diving is a sport Wreck diving is a sport Diving in general is a sport 'Rebreather diving' is not a sport its the delusional obsession with a highly dangerous and often inappropriate piece of equipment
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20th January 2008, 07:09	#42 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,302	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Nailer99) 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? Nailer, Now you've done it...you just had to go and invite me in on a class...the siren call is beginning to take hold . well we'll have to see how this unfolds. I'd definitely be up for a dive soon in any case. if you are interested, drop me a line. g __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
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20th January 2008, 11:08	#43 (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: 2,564	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. . It wasn't really much of an issue, You breath down the PP02 as you descend past the 1.3 mark and the unit then kept me at 1.3 no problem. Obviously sucking in diluent would spike the PP02 a little but again i didn't find it an issue. PP02 would have been about 1.6 at max depth so the odd 0.3 was an additional PP of Nitrogen. End result I had an EAD of 69m We functioned OK. I shot video of the whole thing and drew a map afterward to try and help Louise find the cave entrance we found. She was doing a study on the canyons in the area. We didn't try anything too adventurous we just mosied along at the bottom of the canyon. We did go through a chimney on the ascent at around 50m but apart from that its was easy peasy in clear blue warm stuff. We just followed our VR3s for deco total dive time was 110mins 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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21st January 2008, 04:43	#44 (permalink)
PSquared New Member Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Join Date: Apr 2007 Location: South Africa Posts: 32	Re: How deep to you dive on air diluent? On OC I was a deep air freak regularly doing sub 55m on air, deepest being 102 (admittedly I was 12 years younger, 10kg lighter, a lot fitter and pretty stupid). Since switching to CCR there is absolutely NO reason to dive deep on air as a dil. I switched to machines to make my deep diving safer, not more dangerous. At the risk of sounding like a reformed alcoholic (which I supose I could be likened to) - it's not worth it. Helium is cheap to use on the machine and the machine's drills when you hit the brown smelly stuff require a lot more task loading than on OC - IMHO a tox will hit you sooner because of this. After a dive to 48 using air as dil recently, I've decided 40m tops using air as dil. If He or accurate analysing isn't available, I'll do the deeper stuff on air using OC - less complicated, less to go wrong and IN MY OPINION easier to manage when stoned. __________________ P2 The voices say I wasn't really diving solo
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21st January 2008, 10:09	#45 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,900	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/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! As long as He is available I ALWAYS have it in my dil.. That being said I have multiple 70m+ dives on air dil in places like truk where He was unavailable.. When I first started diving deep (before trimix) and when I was ALOT younger I did multiple 100m dive on air ( Oc ) but usually the limit was 70-75m __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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21st January 2008, 14:52	#46 (permalink)
Ant Slegg Still Learning.... Current Rebreather/s: Ouroboros Other Rebreather/s: Ouroboros Join Date: Nov 2005 Location: Grevenmacher, Luxembourg Posts: 167	Re: How deep to you dive on air diluent? 42m in British waters. However I am trying to log enough hours so that I feel confident enough for trimix. Why? With a fixed ppO2 I really do notice the narcosis (i.e. set to ppO2 to 1.3bar) but go to depths were OC would raise the ppO2 and ppN2 together. I'd like to switch entirely to a trimix based system for all diving. That would be very wasteful on shallower OC dives but so much less so with CCR that (other than availability) I am struggling with why anyone would use air on any dive. __________________ Ant' S Learning to dive since 1990...
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21st January 2008, 15:30	#47 (permalink)
Ben Field CK+Shearwater Current Rebreather/s: Classic Kiss Other Rebreather/s: Sport Kiss Join Date: Aug 2005 Location: London, England Posts: 1,571	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Ant Slegg) I am struggling with why anyone would use air on any dive. Because people are naturally pikeys You buy a Rebreather that costs more than your car and are too tight to buy a Dil fill that costs less than a round? Oh and the real reason (in the UK) is that unless you find a source of helium or premix its getting very difficult to buy __________________ www.hugsac.org.uk Beware Fridge Suck
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21st January 2008, 16:24	#48 (permalink)
PhilSiswick WSKD 0001 Current Rebreather/s: Evolution Other Rebreather/s: Inspiration Vision Join Date: Apr 2006 Location: Oxford, UK Posts: 923	Re: How deep to you dive on air diluent? Quote: (Originally Posted by Ben Field) Because people are naturally pikeys You buy a Rebreather that costs more than your car and are too tight to buy a Dil fill that costs less than a round? Oh and the real reason (in the UK) is that unless you find a source of helium or premix its getting very difficult to buy Just get a largish cylinder and bank it. It's working for me so far and it feels as if I live further from a source of He (or decent pressure O2) than most in the UK. If I'm going somewhere where the skipper or a local shop can do mix, then I take my 'bank' cylinder with me and get it filled to the brim again. That means I always have some for diving in between such trips. It's worked so far - no air diving for me since I did Mod 1 and costs have been much lower than I expected, even though I haven't been getting my mix and O2 from the cheapest locations. Cheers, __________________ Phil No comment on open circuit... it's an evolutionary dead end not really worth discussing here. Dave Sutton, 2007 I have always felt that the dive I am on is not nearly important as the dives I plan to be on the rest of my life. Tom Rose, 2007 www.hugsac.org.uk
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21st January 2008, 17:38	#49 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,302	Re: How deep to you dive on air diluent? for some folks cost may be an issue with He but it seems pretty negligible from what I can tell. I've got more 80's waiting to bank something. I transfill my own o2 and dilluent and buy sorb in bulk...the cost of consumables is probably less than a regular air fill per hour, negligable enough that it's hardly a factor in my choice of diving style, which is how I want it... makes pushing the envelope on gas and sorb calculations hardly a temptation. From what i'm hearing banking He or mix wouldn't add that much in the grand scheme of things, if I go in that direction I'm guessing i'll shift to using it nearly all the time. Hesitations around adding more complexity/dangers and going overboard for the diving I do are all reasons for making a solid assessment of my needs. For me the main reason is probably a lack of familiarity, a kind of superstitious fear that I once had about rebreathers but eventually got over. I'm guessing that once/if I make the transition that there will be no looking back accept to laugh at my hesitation. I guess you could call it a mental block. Difficulty in finding it in remote areas is one more reason, there will be times when it's not available and I will need to know what limits I'm comfortable with on air. this thread is an attempt to see where others draw the bottom line for diving on air diluent, one of the ways i'm assessing how I need to limit my diving or where I need to make the transition to trimix. Luckily I have no qualms about taking my time to figure this out. again, thanks for the feedback folks, keep it coming! g Quote: (Originally Posted by Ben Field) Because people are naturally pikeys You buy a Rebreather that costs more than your car and are too tight to buy a Dil fill that costs less than a round? Oh and the real reason (in the UK) is that unless you find a source of helium or premix its getting very difficult to buy __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 21st January 2008 at 18:47.
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21st January 2008, 18:39	#50 (permalink)
Nailer99 Vita Brevis Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: Seattle, WA, USA Posts: 203	Re: How deep to you dive on air diluent? Most of the CCR divers I dive with simply fill their dil with something like 15/50 as a matter of course- that way they're good to go for any profile they're likely to do around here. I'll let you know when the trimix class dates are after I talk with Mel, but, yeah- soon, in the next couple months...
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