Anyone up for the Coaster on the 24th??

[loanwolf]

It is a neap tide that weekend so currents should not be too bad. Several of us were thinking of doing the coaster on Saturday the 24th and thier is room on the boat. Thier are some other options in the area also in the 180-220 range.

[rjw]

You might as well hit the Sampson while you're in the area.

[loanwolf]

You might as well hit the Sampson while you're in the area.

If it were just Eric, Cam, and myself I would it has been a while. But I chose the coaster or one of the other unknowns under 200 for a few who just got HP-TM certed and are not comfortable to go much below 200 yet. Have to keep nudging them to get them past the 300 mark .

[defied]

Do they have issue with air dives?

D(B)

[loanwolf]

Do they have issue with air dives?

D(B)

They are just not comfortable enough yet with TM and wreck task loading.

[defied]

Air dive it then. That's always fun.

D(B)

[loanwolf]

Air dive it then. That's always fun.

D(B)

CCR air is only good to 130' then you have to go to NM-TM untill 170' then you have to go to HP-TM down to whatever you feel like doing.

[defied]

Why is CCR air only good to 130? Is it not 21%?

D(B)

[defied]

I guess I should say, is 130 your comfort level, or are you stating it as a fact that I can't go past that depth on CCR?

D(B)

[loanwolf]

I guess I should say, is 130 your comfort level, or are you stating it as a fact that I can't go past that depth on CCR?
D(B)

Everything on a CCR is about maximizing your PO2. You use 100% O2 and a diluent to mix on the fly with to keep say a 1.3 PO2 for the whole dive. Your Dill should not have a max PO2 higher than 1.0 so 130' is the max for 21% and still be an effective Diluent. The advantage with CCR and PO2 maximization is say at 130' w/21% on OC you can stay for 10 min max and you start to rack up deco. On CCR at 130' w/21% we start racking up deco at close to 30 min. Significant difference.

[ljjames]

Greg, would eCCR vs mCCR make a difference in your dil max PO2? (assuming you dove an eCCR, which i know you don't)

[loanwolf]

Greg, would eCCR vs mCCR make a difference in your dil max PO2? (assuming you dove an eCCR, which i know you don't)

No it doesn't you need an effective diluent for either mCCR or eCCR so just in case you need to do a diluent flush for some reason. We all have gone past the 130' range with air on CCR and you can, you just loose the ability to effectively Dill flush and knock the PO2 down if you have too. That and you chew though a lot more Dill by going past a 1.0 MOD on your Dill. On a eCCR the computer is going to just not add any O2 and flash at you in your case telling you your PO2 is too high especially when you go below 170' and you cannot knock your PO2 below a 1.3. Or if you are on some of the eCCR's the dame alarm starts to go off and annoy everyone in the water . On most mCCR it will just flash if you have a HUD. Didn't Leon go over this with you yet?

[defied]

So you can go deeper than 130?

And I figure if someone wants to dive on a CCR on air, why not? They could sit on 21% at 1.6, and that'll put them somewhere in the 200ft range.

D(B)

[Romer Treece]

Air dive it then. That's always fun.

D(B)

CCR air is only good to 130' then you have to go to NM-TM untill 170' then you have to go to HP-TM down to whatever you feel like doing.

Hey Greg,
What do you use for your normoxic tm down to 170?

[loanwolf]

So you can go deeper than 130?

And I figure if someone wants to dive on a CCR on air, why not? They could sit on 21% at 1.6, and that'll put them somewhere in the 200ft range.

D(B)

On CCR we are using 100% O2 that is going into the loop all the time though a constant flow orifice (mCCR) or a solenoid (eCCR) and we are only using a 13cf or 19cf tank of gas. So if something happens and you get too much O2 into your loop or if you are dropping fast and your PO2 gets too high you have to use the Diluent to knock it back down to a 1.3. If your PO2 on your Dill gets to much above a 1.0 you may not be able to get your PO2 back down to a 1.3 without having to really flush the whole loop and you can only do that a few times at depth and on really deep dives only once, then you are on bailout. With the lower PO2 on the Dill it takes just a little bit of dill to make a large change on the PO2 in the loop. So you are not wasting a whole lot of gas that has to be purged from the loop. It is not a good practice gas management practice. Since a CCR diver can do 4-90 min dives to 300' on a single 19cf tank of O2 and 19cf tank of TM Dill it costs a CCR diver about $30 for all the consumables to do that. Cheap as hell . And throughout the dive our equivalent air depth is 90' or less if planned right.

[loanwolf]

Air dive it then. That's always fun.

D(B)

CCR air is only good to 130' then you have to go to NM-TM untill 170' then you have to go to HP-TM down to whatever you feel like doing.

Hey Greg,
What do you use for your normoxic tm down to 170?

anything above 16% O2 is normoxic.

I myself am usally always running 10/50 Hypoxic TM, allthough for almost a year and a half I have been trying to use up 2 set's of twins with 20/40 on dives of less than 130' that I made up for a OC friend that was suposed to fly in and go diving and had to cancel the night before he was to get here .

[ljjames]

Of course leon went over it with me. I was asking you specifically. Thank you for your answer.

One reason I went with a CCR is that I love helium. I hate narcosis. I rarely dive air for dil.

Greg, would eCCR vs mCCR make a difference in your dil max PO2? (assuming you dove an eCCR, which i know you don't)

No it doesn't you need an effective diluent for either mCCR or eCCR so just in case you need to do a diluent flush for some reason. We all have gone past the 130' range with air on CCR and you can, you just loose the ability to effectively Dill flush and knock the PO2 down if you have too. That and you chew though a lot more Dill by going past a 1.0 MOD on your Dill. On a eCCR the computer is going to just not add any O2 and flash at you in your case telling you your PO2 is too high especially when you go below 170' and you cannot knock your PO2 below a 1.3. Or if you are on some of the eCCR's the dame alarm starts to go off and annoy everyone in the water . On most mCCR it will just flash if you have a HUD. Didn't Leon go over this with you yet?

[loanwolf]

Of course leon went over it with me. I was asking you specifically. Thank you for your answer.

One reason I went with a CCR is that I love helium. I hate narcosis. I rarely dive air for dil.

Greg, would eCCR vs mCCR make a difference in your dil max PO2? (assuming you dove an eCCR, which i know you don't)

No it doesn't you need an effective diluent for either mCCR or eCCR so just in case you need to do a diluent flush for some reason. We all have gone past the 130' range with air on CCR and you can, you just loose the ability to effectively Dill flush and knock the PO2 down if you have too. That and you chew though a lot more Dill by going past a 1.0 MOD on your Dill. On a eCCR the computer is going to just not add any O2 and flash at you in your case telling you your PO2 is too high especially when you go below 170' and you cannot knock your PO2 below a 1.3. Or if you are on some of the eCCR's the dame alarm starts to go off and annoy everyone in the water . On most mCCR it will just flash if you have a HUD. Didn't Leon go over this with you yet?

Yea I love He too. But I must say I miss narcosis from time to time . I did not think that he would not have gone over that with you, your question supprised me that is all.

But you would be suprised at the number of students I that have come to NM-TM and were never tought any of that by thier CCR instructors. They were just told that you are not certifed to go past 130' so don't do it. With no explination of why not to do it .

[ljjames]

I think there are lots of answers to that question... no one is right or wrong, and you have to be a thinking diver, who doesn't mind asking (or answering) questions to dive CCR's, it just goes with the territory.

for example here is another answer:

http://www.rebreatherpro.com/2009/09/di ... world.html

[defied]

So you can go deeper than 130?

And I figure if someone wants to dive on a CCR on air, why not? They could sit on 21% at 1.6, and that'll put them somewhere in the 200ft range.

D(B)

On CCR we are using 100% O2 that is going into the loop all the time though a constant flow orifice (mCCR) or a solenoid (eCCR) and we are only using a 13cf or 19cf tank of gas. So if something happens and you get too much O2 into your loop or if you are dropping fast and your PO2 gets too high you have to use the Diluent to knock it back down to a 1.3. If your PO2 on your Dill gets to much above a 1.0 you may not be able to get your PO2 back down to a 1.3 without having to really flush the whole loop and you can only do that a few times at depth and on really deep dives only once, then you are on bailout. With the lower PO2 on the Dill it takes just a little bit of dill to make a large change on the PO2 in the loop. So you are not wasting a whole lot of gas that has to be purged from the loop. It is not a good practice gas management practice. Since a CCR diver can do 4-90 min dives to 300' on a single 19cf tank of O2 and 19cf tank of TM Dill it costs a CCR diver about $30 for all the consumables to do that. Cheap as hell . And throughout the dive our equivalent air depth is 90' or less if planned right.

Thanks for the in depth. What I understand is that you can go deeper on air on a CCR, it's just not recommended, nor is it really beneficial as far as cost and cubic feet go.

D(B)

[loanwolf]

I think there are lots of answers to that question... no one is right or wrong, and you have to be a thinking diver, who doesn't mind asking (or answering) questions to dive CCR's, it just goes with the territory.

for example here is another answer:

http://www.rebreatherpro.com/2009/09/di ... world.html

That you are right their are lots of different ways to think about it. On recreational dives 130 or less you for the most part do not have to worry about much it takes so long to rack up any significant ceiling time. The surface is not that far away and bailout obligations are not as tasked. But if you are pushing past 130 and racking up deco then one needs to think a little wiser is my thought (the thinking diver). I run 10/50 most always as I bank it. It is easy to make 50% He and 50% air wola 10/50. Also I don't have to do anything but top tanks all the time and can dive anything down to 300', just no dill flush above 20' or its lights out. I also bank 6/77 for ranges down to 500'. Trying to mix into a 19cf tank is a pain for each MOD like OC. But mixing up 280cf and topping from that is a breeze, I guess that is the none thinking beer drinking diver in me (or the lazy bastard ), top tanks and call it good and have another beer or good glass of wine and chill.

[loanwolf]

So you can go deeper than 130?

And I figure if someone wants to dive on a CCR on air, why not? They could sit on 21% at 1.6, and that'll put them somewhere in the 200ft range.

D(B)

On CCR we are using 100% O2 that is going into the loop all the time though a constant flow orifice (mCCR) or a solenoid (eCCR) and we are only using a 13cf or 19cf tank of gas. So if something happens and you get too much O2 into your loop or if you are dropping fast and your PO2 gets too high you have to use the Diluent to knock it back down to a 1.3. If your PO2 on your Dill gets to much above a 1.0 you may not be able to get your PO2 back down to a 1.3 without having to really flush the whole loop and you can only do that a few times at depth and on really deep dives only once, then you are on bailout. With the lower PO2 on the Dill it takes just a little bit of dill to make a large change on the PO2 in the loop. So you are not wasting a whole lot of gas that has to be purged from the loop. It is not a good practice gas management practice. Since a CCR diver can do 4-90 min dives to 300' on a single 19cf tank of O2 and 19cf tank of TM Dill it costs a CCR diver about $30 for all the consumables to do that. Cheap as hell . And throughout the dive our equivalent air depth is 90' or less if planned right.

Thanks for the in depth. What I understand is that you can go deeper on air on a CCR, it's just not recommended, nor is it really beneficial as far as cost and cubic feet go.

D(B)

you got it. We use so little gas, why risk going past 130 feet with air. Other than for the narcosis . That is why I put the twins on and do a deep air dive every once in a while just to remember how it feels .

[Romer Treece]

Air dive it then. That's always fun.

D(B)

CCR air is only good to 130' then you have to go to NM-TM untill 170' then you have to go to HP-TM down to whatever you feel like doing.

Hey Greg,
What do you use for your normoxic tm down to 170?

anything above 16% O2 is normoxic.

The reason I ask, is with the ongoing debate on what is "normoxic" I wanted your definition to clarify for others out there who are told "the human response to PO2 in the .21-.18 range is considered normal with no noticeable effects. At .17 down to .12, your breathing accelerates." which is NOT normoxic (normal).

Again it's an ongoing debate, just wanted your definition.

[defied]

Normoxic would be .16-.21, correct? The range that humans can breathe at without succumbing to hypoxia, or 02 tox?

D(B)

[Romer Treece]

Normoxic would be .16-.21, correct? The range that humans can breathe at without succumbing to hypoxia, or 02 tox?

D(B)

It would be your own definition of "normal". If your breathing is accelerated using .16 and your fine with that, then it's normoxic. If you are looking for the medical definition of normoxic, it is .20-.21, some of my past instructors taught normoxic to be, .20-21, and some, .18-.21.
Everyones definition could/would be different.