Paul C’s Inspo with back-mounted lungs.

AD_ward9 · 9th May 2007, 14:05

Quote: (Originally Posted by colinicky)

Basically Phi has covered it ,Alex all I can say is that with the bmcl as I have them set up I do not have extra metal work & I can draw 1 full breath at the surface with the wing & drysuit fully inflated ,with everything deflated I get about 1 1/2 full breaths .

"The extra metalwork": I assume you are talking about Paul Channing's Inspo BMCL kit?

Your post and Phi's are confusing in that they appear to refer to some other BMCL setup, under the Paul C's heading on this thread.

In the Paul C's BMCL kit is the backplate shown in the pictures (with folded stainless steel "tubes" for just over half the counterlungs to fit into). Have you managed to assemble it without the backplate? Or are you refering to a completely different BMCL arrangement? If so as well as separating this into two threads, could you be so kind as to post a pic or two showing the set up?

On Phi's point, this is not about the hydrostatic pressure. The tables I post show this is not the issue: that is why I posted them. The issue is water constraining the movement of the counterlungs in the original Paul Channing BMCL kit, and the mod needed to overcome that problem.

Cheers

Alex

decoweenie · 9th May 2007, 14:14

Quote: (Originally Posted by AD_ward9)

...Or are you refering to a completely different BMCL arrangement?...

Sorry for the confusion.

Colin and I were referring to the Dave Thompson BMCL system (with the SS hardware), but the principle what we were talking should apply to both systems.

Anyway, I will stop hi-jacking it now...

colinicky · 9th May 2007, 14:16

Alex
Yes I am reffering to the SS box in Pauls kit

Yes we are reffering to the DT BMCL not Pauls

Alex
its not my idea etc so I am not able to post any pictures as I promised the designer that I would not post any .sorry

Mikel-Deko · 9th May 2007, 14:55

Quote: (Originally Posted by AD_ward9)

It certainly got lighter!

It affects the WOB because the breathing bags have to expand and contract. If the counterlungs are in a tube, it has to push the water out of the tube. That means as well as pumping gas around the loop, your lungs have to pump water up and down. Bottom line is the effect of pumping water up and down is the same as having a very big hydrostatic imbalance.
In the original version, a large part of the CL is equivalent to being in the tube.

There is also an effect that the counterlungs are not completely smooth in the folded SS tube, but that is another story.

Alex

Another silly question.
What about if you have the necesity of inflate the wing full. Does the couterlung have enaught room?
Thanks
Mikel

colinicky · 9th May 2007, 15:59

Mikel
If I remember correctly Paul designed the SS box on the size of a backplate & the backplate "normally" sits inside the bladder of the wing ? If so it shouldn't be a problem

Mikel-Deko · 9th May 2007, 16:21

Quote: (Originally Posted by colinicky)

Mikel
If I remember correctly Paul designed the SS box on the size of a backplate & the backplate "normally" sits inside the bladder of the wing ? If so it shouldn't be a problem

Thanks for the answer but the original medium size wing from the inspi looks a little beet small.
Anyway... my kit is in the way

and i will see once i'got in my hands.

Thanks

Mikel

pchanning · 18th May 2007, 14:10

Firstly, thank you to Alex for his insightful work on the BMCL kit. We have been discussing the issue behind the scenes and it is thanks to him that we are all the wiser.

In relation to the points aforementioned, it is highly recommended to use medium CL's with this kit. Doing so results in only the bottom 50mm (2") of the lung being in the tube so the 'pump' effect is not an issue.

I wear my rig very high on my back. If you have a large frame or wear the unit lower on your back the net effect will be even less CL in the case (assuming one keeps the t-pieces in a fixed position - ie: above ones shoulders where they can be comfortably reached).

I have always advocated the medium lungs as the large ones wouldn't fit very well!

Cheers

Mikel-Deko · 18th May 2007, 14:36

So It is not supossed to put the loops as inside as you can?

Or you just put the "T" pieces where they should be and then you put the all Rebreather as hight as you can???

Thanks
Mikel

PD: Still waiting for my kit

Johnny Christensen · 27th May 2007, 08:38

I just made a minor modification to my setup, that had a huge effect.
Originally I put a couple of fastex clips on the end of the counterlungs, to keep them closer to the harness and shoulder profile. By doing so, I modified a bit on Paul Channing’s original design.
That gave a nice breathing when in shallow water; down to about 30m it was just fine.

But I discovered that going deeper made the WOB rise to an uncomfortable level. At 45m it was definitely higher than I had experienced on the original OTS configuration.
After much thought and despair, where I considered buying another unit that was designed as BMCL to begin with, I finally came to analyse some pictures that I shot of myself in the gear.

In that the counterlungs appeared to be stretched a bit, so I loosened up on the elastic cords in the bottom, that keeps the counterlungs from riding up. I just added a 5cm loop of string between the elastic cords so it was in a relaxed state.
That made the counterlungs ride up higher and be without the stretching.

Yesterday I had a chance to test it on a couple of 46m dives and the unit is now breathing fine again.
So the moral of the story must be, that if you are going to modify on Paul’s original design like I did, you either need to put on some longer elastic cords or add a piece of string between them.

In two weeks time I have a few photo sessions on some pristine wrecks in 70m, now I’m really looking forward to that.

Mikel-Deko · 28th May 2007, 09:45

Hi Johnny,
Thanks for sharing all that information for some of us that are waiting for our kits.

All the pictures that you can share with us will be grateful.

Enjoy you time in 70msw.

Best
Mikel

PD: I think that may be 20-25 kits in the world. Some coments from them will be very helpfull also. Com'on guys.....

9th May 2007, 14:05	#191 (permalink)
AD_ward9 - Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 2,004	Re: Paul C’s Inspo with back-mounted lungs. Quote: (Originally Posted by colinicky) Basically Phi has covered it ,Alex all I can say is that with the bmcl as I have them set up I do not have extra metal work & I can draw 1 full breath at the surface with the wing & drysuit fully inflated ,with everything deflated I get about 1 1/2 full breaths . "The extra metalwork": I assume you are talking about Paul Channing's Inspo BMCL kit? Your post and Phi's are confusing in that they appear to refer to some other BMCL setup, under the Paul C's heading on this thread. In the Paul C's BMCL kit is the backplate shown in the pictures (with folded stainless steel "tubes" for just over half the counterlungs to fit into). Have you managed to assemble it without the backplate? Or are you refering to a completely different BMCL arrangement? If so as well as separating this into two threads, could you be so kind as to post a pic or two showing the set up? On Phi's point, this is not about the hydrostatic pressure. The tables I post show this is not the issue: that is why I posted them. The issue is water constraining the movement of the counterlungs in the original Paul Channing BMCL kit, and the mod needed to overcome that problem. Cheers Alex Last edited by AD_ward9 : 9th May 2007 at 14:09.
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9th May 2007, 14:14	#192 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,487	Re: Paul C’s Inspo with back-mounted lungs. Quote: (Originally Posted by AD_ward9) ...Or are you refering to a completely different BMCL arrangement?... Sorry for the confusion. Colin and I were referring to the Dave Thompson BMCL system (with the SS hardware), but the principle what we were talking should apply to both systems. Anyway, I will stop hi-jacking it now... __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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9th May 2007, 14:16	#193 (permalink)
colinicky RBW Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Mar 2005 Location: uk Posts: 678	Re: Paul C’s Inspo with back-mounted lungs. Alex Yes I am reffering to the SS box in Pauls kit Yes we are reffering to the DT BMCL not Pauls Alex its not my idea etc so I am not able to post any pictures as I promised the designer that I would not post any .sorry __________________ Colin I trust my rebreather completely , I just don't trust the user onwards & downwards
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9th May 2007, 14:55	#194 (permalink)
Mikel-Deko RBW Member Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 470	Re: Paul C’s Inspo with back-mounted lungs. Quote: (Originally Posted by AD_ward9) It certainly got lighter! It affects the WOB because the breathing bags have to expand and contract. If the counterlungs are in a tube, it has to push the water out of the tube. That means as well as pumping gas around the loop, your lungs have to pump water up and down. Bottom line is the effect of pumping water up and down is the same as having a very big hydrostatic imbalance. In the original version, a large part of the CL is equivalent to being in the tube. There is also an effect that the counterlungs are not completely smooth in the folded SS tube, but that is another story. Alex Another silly question. What about if you have the necesity of inflate the wing full. Does the couterlung have enaught room? Thanks Mikel __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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9th May 2007, 15:59	#195 (permalink)
colinicky RBW Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Mar 2005 Location: uk Posts: 678	Re: Paul C’s Inspo with back-mounted lungs. Mikel If I remember correctly Paul designed the SS box on the size of a backplate & the backplate "normally" sits inside the bladder of the wing ? If so it shouldn't be a problem __________________ Colin I trust my rebreather completely , I just don't trust the user onwards & downwards
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9th May 2007, 16:21	#196 (permalink)
Mikel-Deko RBW Member Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 470	Re: Paul C’s Inspo with back-mounted lungs. Quote: (Originally Posted by colinicky) Mikel If I remember correctly Paul designed the SS box on the size of a backplate & the backplate "normally" sits inside the bladder of the wing ? If so it shouldn't be a problem Thanks for the answer but the original medium size wing from the inspi looks a little beet small. Anyway... my kit is in the way and i will see once i'got in my hands. Thanks Mikel __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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18th May 2007, 14:10	#197 (permalink)
pchanning PFO free :) Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: fixed! Posts: 454	Re: Paul C’s Inspo with back-mounted lungs. Firstly, thank you to Alex for his insightful work on the BMCL kit. We have been discussing the issue behind the scenes and it is thanks to him that we are all the wiser. In relation to the points aforementioned, it is highly recommended to use medium CL's with this kit. Doing so results in only the bottom 50mm (2") of the lung being in the tube so the 'pump' effect is not an issue. I wear my rig very high on my back. If you have a large frame or wear the unit lower on your back the net effect will be even less CL in the case (assuming one keeps the t-pieces in a fixed position - ie: above ones shoulders where they can be comfortably reached). I have always advocated the medium lungs as the large ones wouldn't fit very well! Cheers __________________ Cheers Paul The key to enlightenment... is survival.
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18th May 2007, 14:36	#198 (permalink)
Mikel-Deko RBW Member Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 470	Re: Paul C’s Inspo with back-mounted lungs. So It is not supossed to put the loops as inside as you can? Or you just put the "T" pieces where they should be and then you put the all Rebreather as hight as you can??? Thanks Mikel PD: Still waiting for my kit __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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27th May 2007, 08:38	#199 (permalink)
Johnny Christensen RBW Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Apr 2006 Location: Denmark Posts: 306	Re: Paul C’s Inspo with back-mounted lungs. I just made a minor modification to my setup, that had a huge effect. Originally I put a couple of fastex clips on the end of the counterlungs, to keep them closer to the harness and shoulder profile. By doing so, I modified a bit on Paul Channing’s original design. That gave a nice breathing when in shallow water; down to about 30m it was just fine. But I discovered that going deeper made the WOB rise to an uncomfortable level. At 45m it was definitely higher than I had experienced on the original OTS configuration. After much thought and despair, where I considered buying another unit that was designed as BMCL to begin with, I finally came to analyse some pictures that I shot of myself in the gear. In that the counterlungs appeared to be stretched a bit, so I loosened up on the elastic cords in the bottom, that keeps the counterlungs from riding up. I just added a 5cm loop of string between the elastic cords so it was in a relaxed state. That made the counterlungs ride up higher and be without the stretching. Yesterday I had a chance to test it on a couple of 46m dives and the unit is now breathing fine again. So the moral of the story must be, that if you are going to modify on Paul’s original design like I did, you either need to put on some longer elastic cords or add a piece of string between them. In two weeks time I have a few photo sessions on some pristine wrecks in 70m, now I’m really looking forward to that. __________________ www.johnnychristensen.com Wreckphotography from the cold north
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28th May 2007, 09:45	#200 (permalink)
Mikel-Deko RBW Member Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 470	Re: Paul C’s Inspo with back-mounted lungs. Hi Johnny, Thanks for sharing all that information for some of us that are waiting for our kits. All the pictures that you can share with us will be grateful. Enjoy you time in 70msw. Best Mikel PD: I think that may be 20-25 kits in the world. Some coments from them will be very helpfull also. Com'on guys..... __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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