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.


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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.