GUE JJ configuration

[Tassi Devil Diver]

The thing smacks of a rebreather configuration designed by committee and work shopped to hell and back to solve problems that don't exist. No doubt involving the greatest GUE minds, and they come up with a rig that weighs the best part of 60kg FFS.

I have no problem with GUE I like what they do, and how they go about it, but they screwed the pooch when it comes to CCR.

 

[PfcAJ]

The thing smacks of a rebreather configuration designed by committee and work shopped to hell and back to solve problems that don't exist. No doubt involving the greatest GUE minds, and they come up with a rig that weighs the best part of 60kg FFS.

I have no problem with GUE I like what they do, and how they go about it, but they screwed the pooch when it comes to CCR.

It came from the same bailout config used to explore caves the WKP, Roubidoux, Mexico, France, etc.

How much it weighs out of the water isn’t really a concern. We’ve been putting LP120s on the sides of rebreathers for over 20 years.

 

[Wibble]

It came from the same bailout config used to explore caves the WKP, Roubidoux, Mexico, France, etc.

How much it weighs out of the water isn’t really a concern. We’ve been putting LP120s on the sides of rebreathers for over 20 years.

There's little doubt that in that highly specialised environment of long caves without tight restrictions the "GUE config" JJ with a pair of large manifolded diluent cylinders is the right tool for the job.

However, this minor use case configuration is overkill in generic environments where bailouts are off of one or more stage cylinders which are chosen for the depth and length of the dive. Using small diluent cylinders results in a smaller, more flexible, cheaper and lighter rig.

There's many alternative rebreather configurations which would also be better for specific use cases: sidemount for a lower profile; chestmount where the unit can be pushed forwards; backmount with a bailout 'breather; double backmount; backmount using sidemounted dilout, etc., etc.


Appreciate that I am utterly unqualified to even speak of this as I've not been exposed to the GUE training, standards and whole team-based approach to diving, let alone using a GUE JJ.

 

[Tassi Devil Diver]

Yes I realise that units like the RB80 used by GUE in those projects utilise the large onboard tanks, and the gas in those tanks is needed to drive the unit being a gas extender, and I can see the clear rational if you have a need to use one of those units and the team to support those dives. Like the Wet Mules guys using the massive twin meg for their insane cave dives it has a purpose.

However, the GUE configured JJ won't get you any deeper, longer, further than the standard JJ or any other back mounted rebreather. It's claimed it allows a greater quantity of deep bailout to be carried in the twin 7L tanks, similar OC procedures etc. My rEvo (or any other back mounted rebreather) with a 11L deep bailout and 3L on board dil provides a similar amount deep bailout as the twin 7's (where I can access 3100L of on board dil and off board deep bailout through my BOV). As for OC procedures I have never found myself reaching high for valve shutdowns during boom drills or attempting to deploy a nonexistent long hose from around my neck during gas sharing exercises (I have long hose stashed on my deep bailout for gas sharing if in the unlikely event it's ever needed). Those OC skills were quickly put aside following the completion of MOD 1 and obviously further reinforced during subsequent training.

The GUE JJ configuration is trying address issues that don't exist.

 

[PfcAJ]

Yes I realise that units like the RB80 used by GUE in those projects utilise the large onboard tanks, and the gas in those tanks is needed to drive the unit being a gas extender, and I can see the clear rational if you have a need to use one of those units and the team to support those dives. Like the Wet Mules guys using the massive twin meg for their insane cave dives it has a purpose.

However, the GUE configured JJ won't get you any deeper, longer, further than the standard JJ or any other back mounted rebreather. It's claimed it allows a greater quantity of deep bailout to be carried in the twin 7L tanks, similar OC procedures etc. My rEvo (or any other back mounted rebreather) with a 11L deep bailout and 3L on board dil provides a similar amount deep bailout as the twin 7's (where I can access 3100L of on board dil and off board deep bailout through my BOV). As for OC procedures I have never found myself reaching high for valve shutdowns during boom drills or attempting to deploy a nonexistent long hose from around my neck during gas sharing exercises (I have long hose stashed on my deep bailout for gas sharing if in the unlikely event it's ever needed). Those OC skills were quickly put aside following the completion of MOD 1 and obviously further reinforced during subsequent training.

The GUE JJ configuration is trying address issues that don't exist.

That’s not the purpose of the tanks on the rb80. In almost all instances, we use stages to drive the rebreather. The backmounted tanks are solely for bailout (like the GUE JJ).

The same issues exist for the JJ as do the RB80. And you see it in practice all the time with dudes taking SLIM amounts of bailout, suspect gas choices, team bailout, etc, because they lack the space to carry it in a reasonable manner. BM bailout largely solves that.

 

[Pavao]

.However, the GUE configured JJ won't get you any deeper, longer, further than the standard JJ or any other back mounted rebreather. It's claimed it allows a greater quantity of deep bailout to be carried in the twin 7L tanks, similar OC procedures etc. My rEvo (or any other back mounted rebreather) with a 11L deep bailout and 3L on board dil provides a similar amount deep bailout as the twin 7's (where I can access 3100L of on board dil and off board deep bailout through my BOV).

The GUE JJ configuration is trying address issues that don't exist.

Twin 7L which is filled to 3500-3600PSI will have about 70% more gas than an 11L, that’s not even close to being similar amounts of deep bailout.
Not to mention, if I need more bailout, I’ll add an 11L, that’d be my first 11L, you’d be on your second with more bottles clipped to you and still less bailout than me.

If you still don’t get it, consider that whichever way you carry the maximum amount of bailout bottles you can carry, I can do the same, plus an extra ~18 liters of deep bailout. Or, when you’ve reached the limit of bottles you can carry, I’d still have space for more even though I’d already be carrying more than you.

 

[inquis]

Using the real estate back there is increasingly desirable as the number of BO gases/bottles grows. With my OC diving, I much preferred to carry two bottles instead of three, and that hasn't changed one bit after moving to CC. The dry-weight tradeoff is one I'm still able to accept at present.

 

[211ratsbud]

Using the real estate back there is increasingly desirable as the number of BO gases/bottles grows. With my OC diving, I much preferred to carry two bottles instead of three, and that hasn't changed one bit after moving to CC. The dry-weight tradeoff is one I'm still able to accept at present.

I'm 6'6" 300#. Carrying 3l on my back just don't look right

 

[patrick.danko]

Lots of good dialog in this thread. I'd throw out one other scenario ...while you may be diving in a team of similarly configured and trained divers, it isn't always the case that those are the people you may need to donate to.

While diving a wreck popular with both tec and recreational divers a couple of years ago, I had a nearly OOA, solo, panicked diver approach looking for help. My buddy and I were on the line doing deco. Having unimpeded access to donatable OC gas was front of mind for me in that situation.

 

[AJ]

While diving a wreck popular with both tec and recreational divers a couple of years ago, I've had a nearly OOA, solo, panicked diver approach looking for help. My buddy and I were on the line doing deco. Having unimpeded access to donatable OC gas was front of mind for me in that situation.

In my case it's right beside me. One grab is all I need to provide air. Personally I don't think there's much benefit having it tucked away under the loop.