DIR- GUE Thoughts on Halcyon Symbios as an entry point into CCR diving vs a specialized tool?

[PEDiver]

The RB80 with al40s or lp50s in "non-cave mode" is much more aligned with their past perspectives on O2 cells and electronics in general. You can't put lp85s on the JJ and run it as a "cave CCR" which is a big flaw -although you can SM your BO on the JJ that's not what's happening. People continue to use lp50s even though that's a pitiful amount of on-board BO.

This is one thing that has always confused me as it relates to the GUE JJ configuration. GUE's philosophy originated out of cave diving and the WKPP and the RB80 makes a ton of sense. But to then turn around and bless the JJ with LP50s and encourage that as an option for cave diving makes no sense to me. If you're doing a big cave dive, are you just taught to bring a s***-ton of safety bottles to drop? The KUR configuration (BM unit with SM bailout) makes a lot more sense for cave diving. Need more bailout? Easy, just SM a bigger tank. It's effortless to switch from 80s to 85s to 120s in a pinch depending on the dive. I don't see that modularity in the GUE JJ configuration.

 

[ginti]

This is one thing that has always confused me as it relates to the GUE JJ configuration. GUE's philosophy originated out of cave diving and the WKPP and the RB80 makes a ton of sense. But to then turn around and bless the JJ with LP50s and encourage that as an option for cave diving makes no sense to me. If you're doing a big cave dive, are you just taught to bring a s***-ton of safety bottles to drop? The KUR configuration (BM unit with SM bailout) makes a lot more sense for cave diving. Need more bailout? Easy, just SM a bigger tank. It's effortless to switch from 80s to 85s to 120s in a pinch depending on the dive. I don't see that modularity in the GUE JJ configuration.

GUE evolved over time and had so many projects in OW. I believe the JJ was born out of these projects. Indeed, all the deep sea GUE divers I know really love the GUE JJ, they consider it the perfect machine for deep OW diving, but I know nobody who would consider it the perfect machine for cave diving.

In that regard, I know nobody who has in mind the perfect rebreather for cave diving...

 

[flymolo]

Back when Diepolder was open (FDW), there were instances of lp50s being used for bailout with the JJ in a 300ft+ deep cave because the damn thing is too wide to put larger diameter tanks on it. Not smart.

@PfcAJ, I know the onboard gas is not a lot with just LP50s, but what are your thoughts on carrying additional bottom stages to make up the difference? I always thought that was a reasonable compromise.

 

[rjack321]

In that regard, I know nobody who has in mind the perfect rebreather for cave diving...

Assuming you want an actual CCR not an RB80 and you're in big caves you can look here.

Photo Gallery – KARST UNDERWATER RESEARCH

karstunderwater.org

This is a polished backmount CCR/ sidemount BO equipment system where all the drawbacks and positives have been thoughtfully weighed. For SM sized caves/circumstances, the jury is still out, partly because things like suit gas volumes (and where to put it) start to seriously cramp your configuration.

 

[ginti]

Assuming you want an actual CCR not an RB80 and you're in big caves you can look here.

Photo Gallery – KARST UNDERWATER RESEARCH

karstunderwater.org

This is a polished backmount CCR/ sidemount BO equipment system where all the drawbacks and positives have been thoughtfully weighed. For SM sized caves/circumstances, the jury is still out, partly because things like suit gas volumes (and where to put it) start to seriously cramp your configuration.


View attachment 885194

I was tagging you and @PfcAJ to hear your thoughts but then I said nah... Thanks a lot, much appreciated

At this point, @PfcAJ if you want to add your perspective

 

[rjack321]

@PfcAJ, I know the onboard gas is not a lot with just LP50s, but what are your thoughts on carrying additional bottom stages to make up the difference? I always thought that was a reasonable compromise.

Unfortunately when folks have a nail they reach for a hammer. It would be better to remove the 50s convert the JJ back to the L/R 3Ls with O2 in one and suit gas in the other. Then SM much larger deep BO tanks. While not manifolded together you can put as much as 2x lp50s worth of gas in a single lp108. Basically double your onboard BO and only then add stages. But folks trained in the backmounted lp50s way are generally not doing that.

 

[RedSix]

but I know nobody who would consider it the perfect machine for cave diving.

What is the "perfect machine" for cave diving? Does it exist?
What to bring strongly depends on the cave! There are caves, where the GUE JJ is okay. Eg Ressel in France. Very wide and deepish.
The other thing is: nobody forces GUE divers to put LP50s (or in Europe 7L or even 8.5L steels) on their JJ. The bottles should be manifolded, but this also works fine for eg. 4L (od 100mm) or even 3L bottles. And if needed, even a GUE diver can re-build the stock configuration and dive it. He will need to adjust, but it is not that hard. Thinking diver...

 

[ginti]

What is the "perfect machine" for cave diving? Does it exist?
What to bring strongly depends on the cave! There are caves, where the GUE JJ is okay. Eg Ressel in France. Very wide and deepish.
The other thing is: nobody forces GUE divers to put LP50s (or in Europe 7L or even 8.5L steels) on their JJ. The bottles should be manifolded, but this also works fine for eg. 4L (od 100mm) or even 3L bottles. And if needed, even a GUE diver can re-build the stock configuration and dive it. He will need to adjust, but it is not that hard. Thinking diver...

This is exactly what I plan to do and what most people (in my circle) using the GUE configuration in caves are doing (except for the 3l with the GUE config - not a lot of bailout, to me the standard configuration makes more sense at this point). Spot on.

And, indeed, great machine for caves with space: not only in France, even in Sardinia (although shallow here, lots of time in OC as well), even in Mexico some caves are absolutely wide enough to accommodate it.

But, as you mentioned, caves are all different and finding a machine that is good enough for lost caves is hard if not impossible.

Some people I know diving mostly caves go for Sidewinder or Gemini given they allow for some restrictions, but even these machines have their own limits.

Fully agree with you

 

[rjack321]

The other thing is: nobody forces GUE divers to put LP50s (or in Europe 7L or even 8.5L steels) on their JJ. The bottles should be manifolded, but this also works fine for eg. 4L (od 100mm) or even 3L bottles. And if needed, even a GUE diver can re-build the stock configuration and dive it. He will need to adjust, but it is not that hard. Thinking diver...

Sure people can reconfigure, but the GUE folks aren't actually trained or familiar with how to dive with 2x 3L. So they aren't reconfiguring into a more traditional JJ rig nevermind going the full KUR route with 3L of suit gas and large sidemounted steel BOs. The "just add stages" mentality is a weakness in how GUE CCR divers approach cave dives on that unit. They are taught that way so they dive it that way, despite the major inconsistency with how BO is approached on the RB80. Nobody with put 50s on an RB80, add a whole slew of stages and go deep or long cave diving - that would be laughable.

For the record I have 100+ dives rigged in the KUR approach, just with a Meg not a JJ. For a backmounted cave CCR, the KUR approach is as close to ideal as can be achieved.

I am guessing the new symbios unit will have similar levels of GUE mental gymnastics why it's suitable for cave diving.

 

[ginti]

Sure people can reconfigure, but the GUE folks aren't actually trained or familiar with how to dive with 2x 3L.

Would you suggest starting from scratch with a mod1 class for that configuration? Why/Why not?

So they aren't reconfiguring into a more traditional JJ rig nevermind going the full KUR route with 3L of suit gas and large sidemounted steel BOs. The "just add stages" mentality is a weakness in how GUE CCR divers approach cave dives on that unit. They are taught that way so they dive it that way, despite the major inconsistency with how BO is approached on the RB80. Nobody with put 50s on an RB80, add a whole slew of stages and go deep or long cave diving - that would be laughable.

This is not my level, so I am asking out of curiosity. How would you actually do it?