IPO and back mounted counter lungs

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I can't believe people still listen to that guy

I can't believe he's still allowed here. Between the shilling and attempts to sell his crap in every thread, to the outright lies he pushes to try and do so, I can't for the life of me figure out why he's allowed to stick around.
 
I can't believe he's still allowed here. Between the shilling and attempts to sell his crap in every thread, to the outright lies he pushes to try and do so, I can't for the life of me figure out why he's allowed to stick around.
I am all for free speech. As long as there are experienced rebreather divers who can expose the snake oil salesmen.
 
Sorry SR, I've only just seen your post. With proper engineering, BMCL will breathe better across the full spectrum of unmanned test requirements than OTS. It's not a guess. Given suitably indepth unmanned testing eventually being been done on OTS units and the results (with calibration) published, anyone can readily do this comparison against that offered on the Apoc. Deep Life Design Team: Selected Design Validation Reports for DL & Open Safety Equipment Ltd's Rebreathers
OSEL even sell a breathing simulator to make this R&D easier for rebreather manufacturers, so they can offer improved products with better breathing performance. http://www.opensafety.co.uk/files/Datasheet_iBreatheMkIV_1906.pdf

In response to your specific question, note the shape and material used in the Apoc IV & II counterlungs. Some of this is disclosed in the FMECA http://www.deeplife.co.uk/or_files/FMECA_OR_V4_140831.pdf
You won't get the high breathing performance offered if you replaced the CLs with MSR waterbags or added a SS backplate and wing into the equation. This is why the design (noting the Apoc is a spin-off from the 350m rated commercial saturation diving primary life support system that DL was originally commissioned to design) started from a clean sheet of paper, with money not being a factor, and anything that didn't improve performance (or hindered user safety) was critically examined.


I'm in full agreement with you on the importance of WOB. But can't see OSEL offering OTS unless a military client has sufficient mission justification for the need and accepts the decrease in breathing performance. In which case, like with the various Incursion models OSEL is shipping, this wouldn't be offered to recreational divers.

You'll obviously improve the PRISMs WOB with fitment of the ALVBOV, which should even subjectively, be noticeable; however, I don't recall that the USN published WOB for the PRISM (don't think SM/PR tested it?) and without that we can't discuss just how much of a WOB improvement you'd see swapping to an Apoc. Still like to see one fitted with analogue secondary and modern primary HUD though.

Under the current 14143 standard there is an elastance limit, a breathing resistance limit and a work of breathing limit. There are also hydrostatic limits. The elastance, and hydrostatic limits are related but independent of WOB.

Hi Brad, yes the NEDU did test the Prism WOB, I don’t remember what it was, maybe 1.6? It was one of the lower figures, there’s a chart somewhere in an old RBW thread.

And yes, an analog secondary, high output sensors with a modern HUD would be my most preferred design. And if you also could switch from solenoid to needle valve CMF addition for sawtooth/cave type profiles, that would be ideal...

Thanks for all the links and graphs, but it’s a bit hard to sift through all that information to find an explanation for how BMCLs can overcome the hydrostatic head experienced with near horizontal or worse, head down/descending trim. Can you explain in laymen’s terms how this is achieved? Even with BMCLs as close to the back as possible, the diver’s lungs are still closer to the front of the chest than the back. I just don’t see how with all other design elements being equal, OTS would not breathe better given the hydrostatic head encountered in most common swim positions...
 
At least some BMCLs "wrap around" the lower back onto the sides so part of the lung volume is at the same depth as the diver's lungs when in flat trim at least.
 
At least some BMCLs "wrap around" the lower back onto the sides so part of the lung volume is at the same depth as the diver's lungs when in flat trim at least.

Which CCR(s) are you referring to?

While that may be an improvement, aren’t the lungs higher up in the chest cavity as well as being closer to the front of the chest? Wouldn’t wrapping the lungs around higher up than the lower back, under the arms, bring them even closer to the lungs?
 
Which CCR(s) are you referring to?

While that may be an improvement, aren’t the lungs higher up in the chest cavity as well as being closer to the front of the chest? Wouldn’t wrapping the lungs around higher up than the lower back, under the arms, bring them even closer to the lungs?

The Mk1 Pelagian lungs are essentially “side-mounted” counterlungs that most closely match the lung centroid of the diver in virtually all positions except sideways.

However, they are, for most people, unacceptably intrusive as the clutter up both the front, and sides of the diver in places where we need to be trim and unobtrusive. They literally obstruct every d-ring except the butt and scooter rings. Hence why most Pelagian divers have switched to BMCL’s.
 
The Mk1 Pelagian lungs are essentially “side-mounted” counterlungs that most closely match the lung centroid of the diver in virtually all positions except sideways.

However, they are, for most people, unacceptably intrusive as the clutter up both the front, and sides of the diver in places where we need to be trim and unobtrusive. They literally obstruct every d-ring except the butt and scooter rings. Hence why most Pelagian divers have switched to BMCL’s.

Thanks JohhnyC, I’m familiar with the Pelagian CLs, very sensible design aside from the D ring issues you mentioned. But it sounded like rjack was speaking of another CCR with the lungs placed mostly on the back?
 
Thanks JohhnyC, I’m familiar with the Pelagian CLs, very sensible design aside from the D ring issues you mentioned. But it sounded like rjack was speaking of another CCR with the lungs placed mostly on the back?
The kiss sidewinder lung (single) wraps across the small of my back and extends down each side by my kidney about 4-6"
The kiss orca and spirit lte CLs both do the same (those units have 2 CLs)

At least in the sidewinder's case you couldn't have the lungs higher as the neck bungies from sidemounted bailout would compress them. The WOB from the wrap around CL is fabulous in trim, it does get kind of crappy if you go head up or head down because your lungs and entire diaphragm end up above or below the CL. Its not impossible to breathe and the unit is still divable in a vertical position - but it does take a lot of work. I had to go vertical in a cave I was diving a couple weeks ago and my lungs vented (via my nose & mouth) and all my suit gas dumped and I was not a happy camper as the water was 41F (5C). Worst part was the cave ended and it was all for naught.
 
The kiss sidewinder lung (single) wraps across the small of my back and extends down each side by my kidney about 4-6"
The kiss orca and spirit lte CLs both do the same (those units have 2 CLs)

At least in the sidewinder's case you couldn't have the lungs higher as the neck bungies from sidemounted bailout would compress them. The WOB from the wrap around CL is fabulous in trim, it does get kind of crappy if you go head up or head down because your lungs and entire diaphragm end up above or below the CL. Its not impossible to breathe and the unit is still divable in a vertical position - but it does take a lot of work. I had to go vertical in a cave I was diving a couple weeks ago and my lungs vented (via my nose & mouth) and all my suit gas dumped and I was not a happy camper as the water was 41F (5C). Worst part was the cave ended and it was all for naught.

Thanks for the detailed info. Are you using the Sidewinder as a BO CCR?
 
Thanks for the detailed info. Are you using the Sidewinder as a BO CCR?
I know a few people are. I use a Meg with "top of shoulder" CLs for wreck dives. The sidewinder is for cave dives. 95% of my dives are 10-220ft, maybe 5% are deeper than 220ft and my max is around 305ft. I use al80s in open water and lp85s or hp130s in cave for OC bailout. I don't see a need for a BO CCR in my diving in the foreseeable future. Right now on both units combined I think I have 225-240hrs, mostly in cold to very cold water.
 

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