Exceeding Interstage Pressure on COPIS

Nailer99 · 11th June 2008, 05:37

OK, so, I'm not doing these dives yet, but I'm working up to it. I know that at a certain depth, somewhere between 270-280 fsw, ambient pressure will overcome the IP on my COPIS, and I won't be able to add 02 any more at that point. When I first asked how to overcome this, I was given the stock answer: "just plug in offboard." Which makes sense. What I'm curious about is the specific details about how those of you that are doing these dives are doing this- do you carry a full 40 cf bottle of 100%, along with an 80 of trimix, and another 80 of eanx? (This question kind of gets into bailout strategies as well, for obvious reasons)
It occured to me today that one might only need a very small amount of offboard 02 at depth- does anyone use a smaller offboard 02 bottle for this purpose? Like a 6-14cf?

**Gill Envy** · 11th June 2008, 06:05

Hey josh, I was told a 13cf would be plenty... I have a few worthington 13's for sale, if that ends up being what you want then pm me.

g

Nailer99 · 11th June 2008, 06:24

Quote: (Originally Posted by Gill Envy)

Hey josh, I was told a 13cf would be plenty... I have a few worthington 13's for sale, if that ends up being what you want then pm me.

g

Thanks, George! I'm curious as to how people might be rigging this, if that's the case- pictures would be appreciated.

mempilot · 11th June 2008, 07:11

My 13's for sale.

http://www.rebreatherworld.com/rebre...13-cf-2-a.html

Rob Dobson · 11th June 2008, 09:53

You can just use your rich mix, be it 60%, 80% or O2 (you do already have a LP inflator hose on your BO 1st stages right?). Alternatively you can take a small suit inflator bottle like a 1L and mount that on your rig using something like Shadow Mounts and have that always connected your off-board port.

Jim · 11th June 2008, 11:48

......... Or, knowing you are going to exceed the Interstage Pressure on COPIS go for the 'ordinary' Meg ?

zoo_diver · 11th June 2008, 13:40

Quote: (Originally Posted by Jim)

......... Or, knowing you are going to exceed the Interstage Pressure on COPIS go for the 'ordinary' Meg ?

Ordinary Meg? I don't suppose by chance you are admiting that the COPIS is superior other Megs are you? If I walked into a dive shop and said "Hey, do you have an ordinary Meg?" Would they give me an Apex?

COPIS II = Extra-Ordinary Meg

In good fun....

zoo_diver · 11th June 2008, 13:49

[quote=Nailer99;191778]It occured to me today that one might only need a very small amount of offboard 02 at depth- does anyone use a smaller offboard 02 bottle for this purpose? Like a 6-14cf?quote]

In an effort to keep things simple, I would rather not carry an extra bottle. I don't like having extra stuff hanging off of me and it's just one more thing to worry about and that could fail. As you noted above, it is only a small amount. I do the math and plan for the extra gas in my stage/sling.

Jim · 11th June 2008, 14:51

Quote: (Originally Posted by zoo_diver)

Ordinary Meg? I don't suppose by chance you are admiting that the COPIS is superior other Megs are you? If I walked into a dive shop and said "Hey, do you have an ordinary Meg?" Would they give me an Apex?

COPIS II = Extra-Ordinary Meg

In good fun....

And I thought my comment was courting controversy !!

mempilot · 11th June 2008, 14:55

I dive a standard Meg, and I don't know much about the COPIS, but wouldn't flying the unit totally manually work in this case? Just press the manual gas bypass for O2 off the onboard O2 bottle? No need to carry offboard O2.

11th June 2008, 05:37	#1 (permalink)
Nailer99 RBW Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: Seattle, WA, USA Posts: 280	Exceeding Interstage Pressure on COPIS OK, so, I'm not doing these dives yet, but I'm working up to it. I know that at a certain depth, somewhere between 270-280 fsw, ambient pressure will overcome the IP on my COPIS, and I won't be able to add 02 any more at that point. When I first asked how to overcome this, I was given the stock answer: "just plug in offboard." Which makes sense. What I'm curious about is the specific details about how those of you that are doing these dives are doing this- do you carry a full 40 cf bottle of 100%, along with an 80 of trimix, and another 80 of eanx? (This question kind of gets into bailout strategies as well, for obvious reasons) It occured to me today that one might only need a very small amount of offboard 02 at depth- does anyone use a smaller offboard 02 bottle for this purpose? Like a 6-14cf?
(Offline)

11th June 2008, 06:05	#2 (permalink)
Gill Envy Shearwater Copis Divers Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,347	Re: Exceeding Interstage Pressure on COPIS Hey josh, I was told a 13cf would be plenty... I have a few worthington 13's for sale, if that ends up being what you want then pm me. g __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°>
(Offline)

11th June 2008, 06:24	#3 (permalink)
Nailer99 RBW Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Jan 2007 Location: Seattle, WA, USA Posts: 280	Re: Exceeding Interstage Pressure on COPIS Quote: (Originally Posted by Gill Envy) Hey josh, I was told a 13cf would be plenty... I have a few worthington 13's for sale, if that ends up being what you want then pm me. g Thanks, George! I'm curious as to how people might be rigging this, if that's the case- pictures would be appreciated.
(Offline)

11th June 2008, 07:11	#4 (permalink)
mempilot Eric Stadtmueller Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,708	Re: Exceeding Interstage Pressure on COPIS My 13's for sale. http://www.rebreatherworld.com/rebre...13-cf-2-a.html __________________ Eric Stadtmueller, otherwise known as, MEM "Da Pilot"
(Offline)

11th June 2008, 09:53	#5 (permalink)
Rob Dobson RBW Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Dec 2007 Location: Oxford Posts: 100	Re: Exceeding Interstage Pressure on COPIS You can just use your rich mix, be it 60%, 80% or O2 (you do already have a LP inflator hose on your BO 1st stages right?). Alternatively you can take a small suit inflator bottle like a 1L and mount that on your rig using something like Shadow Mounts and have that always connected your off-board port.
(Offline)

11th June 2008, 11:48	#6 (permalink)
Jim Lovable Cockhead ! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Join Date: Jun 2005 Location: Purley, UK Posts: 152	Re: Exceeding Interstage Pressure on COPIS ......... Or, knowing you are going to exceed the Interstage Pressure on COPIS go for the 'ordinary' Meg ? __________________ Jim Spence
(Offline)

11th June 2008, 13:40	#7 (permalink)
zoo_diver Is it snack time yet? Current Rebreather/s: Evolution Megalodon Sport Kiss Other Rebreather/s: Megalodon Join Date: Jun 2007 Location: Suffolk, VA Posts: 259	Re: Exceeding Interstage Pressure on COPIS Quote: (Originally Posted by Jim) ......... Or, knowing you are going to exceed the Interstage Pressure on COPIS go for the 'ordinary' Meg ? Ordinary Meg? I don't suppose by chance you are admiting that the COPIS is superior other Megs are you? If I walked into a dive shop and said "Hey, do you have an ordinary Meg?" Would they give me an Apex? COPIS II = Extra-Ordinary Meg In good fun....
(Offline)

11th June 2008, 13:49	#8 (permalink)
zoo_diver Is it snack time yet? Current Rebreather/s: Evolution Megalodon Sport Kiss Other Rebreather/s: Megalodon Join Date: Jun 2007 Location: Suffolk, VA Posts: 259	Re: Exceeding Interstage Pressure on COPIS [quote=Nailer99;191778]It occured to me today that one might only need a very small amount of offboard 02 at depth- does anyone use a smaller offboard 02 bottle for this purpose? Like a 6-14cf?quote] In an effort to keep things simple, I would rather not carry an extra bottle. I don't like having extra stuff hanging off of me and it's just one more thing to worry about and that could fail. As you noted above, it is only a small amount. I do the math and plan for the extra gas in my stage/sling.
(Offline)

11th June 2008, 14:51	#9 (permalink)
Jim Lovable Cockhead ! Current Rebreather/s: Megalodon Other Rebreather/s: Inspiration Classic Join Date: Jun 2005 Location: Purley, UK Posts: 152	Re: Exceeding Interstage Pressure on COPIS Quote: (Originally Posted by zoo_diver) Ordinary Meg? I don't suppose by chance you are admiting that the COPIS is superior other Megs are you? If I walked into a dive shop and said "Hey, do you have an ordinary Meg?" Would they give me an Apex? COPIS II = Extra-Ordinary Meg In good fun.... And I thought my comment was courting controversy !! __________________ Jim Spence
(Offline)

11th June 2008, 14:55	#10 (permalink)
mempilot Eric Stadtmueller Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,708	Re: Exceeding Interstage Pressure on COPIS I dive a standard Meg, and I don't know much about the COPIS, but wouldn't flying the unit totally manually work in this case? Just press the manual gas bypass for O2 off the onboard O2 bottle? No need to carry offboard O2. __________________ Eric Stadtmueller, otherwise known as, MEM "Da Pilot"
(Offline)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode