GUE-JJ hose routing versus Fathom Tech Rig hose routing

[211ratsbud]

I currently have my rig routed similar to a fathom however it does add some slight complexity. I can see how the GUE JJ routing is a little cleaner. Aside from being able to plug in offboard dill to the Mav I'm not certain why the onboard dill out is routed the same way in offboard would plug in on the fathom. Is the Fathom configuration just a legacy of the cave configuration plumbing ?

 

[divingx]

That way you can always have a breathable gas supplying BOV when diving with hypoxic mix.

 

[tbone1004]

I currently have my rig routed similar to a fathom however it does add some slight complexity. I can see how the GUE JJ routing is a little cleaner. Aside from being able to plug in offboard dill to the Mav I'm not certain why the onboard dill out is routed the same way in offboard would plug in on the fathom. Is the Fathom configuration just a legacy of the cave configuration plumbing ?

How would you suggest it get plumbed in? The JJ has a cleaner routing because it doesn't allow offboard dil to be plumbed in. The Fathom has you plug everything in so you know what you're breathing at any given time. Different priorities based on the types of diving that do it.

Don't know this for sure, but since Lundgren was really the one getting the JJ sorted it makes sense that not plugging offboard in was a priority of his since his real expertise is in deep wrecks where that isn't a priority. In contrast, Charlie does extreme long range cave diving where it's extremely important to be able to plug in stage bottles or deco bottles. For the vast majority of divers this doesn't matter at all, but if I NEED stage bottles to get out from where I'm going in a cave then I want to be able to plug them into the breather if the exit goes really sideways.

@divingx I wouldn't say breathable gas when diving hypoxic was the priority, it's much more the ability to plug in stage/deco bottles if an exit goes sideways. The fact that hypoxic mix is breathable is a perk, but since even 10% is breathable at your oxygen stop, it's definitely not the primary justification.

 

[kierentec]

How would you suggest it get plumbed in? The JJ has a cleaner routing because it doesn't allow offboard dil to be plumbed in. The Fathom has you plug everything in so you know what you're breathing at any given time. Different priorities based on the types of diving that do it.

Don't know this for sure, but since Lundgren was really the one getting the JJ sorted it makes sense that not plugging offboard in was a priority of his since his real expertise is in deep wrecks where that isn't a priority. In contrast, Charlie does extreme long range cave diving where it's extremely important to be able to plug in stage bottles or deco bottles. For the vast majority of divers this doesn't matter at all, but if I NEED stage bottles to get out from where I'm going in a cave then I want to be able to plug them into the breather if the exit goes really sideways.

@divingx I wouldn't say breathable gas when diving hypoxic was the priority, it's much more the ability to plug in stage/deco bottles if an exit goes sideways. The fact that hypoxic mix is breathable is a perk, but since even 10% is breathable at your oxygen stop, it's definitely not the primary justification.

The Fathom config also allows you to use a different drive gas than your OC bailout. A ginnie springs dive is a great example. Ideal dil would be 21/35, but that's not a great OC bailout or SCR gas. So with the fathom config, you can drive the unit with a 21/35 stage and still have 32% on your back for bailout or to run SCR if you need to.

 

[tbone1004]

The Fathom config also allows you to use a different drive gas than your OC bailout. A ginnie springs dive is a great example. Ideal dil would be 21/35, but that's not a great OC bailout or SCR gas. So with the fathom config, you can drive the unit with a 21/35 stage and still have 32% on your back for bailout or to run SCR if you need to.

true, it's also absolutely wild what happens to deco times when you get the helium out of the loop. Offboard dil is a 100% requirement for me when cave diving. In the ocean it's a "nice to have" but not what I would consider "mandatory"

 

[divingx]

@divingx I wouldn't say breathable gas when diving hypoxic was the priority, it's much more the ability to plug in stage/deco bottles if an exit goes sideways. The fact that hypoxic mix is breathable is a perk, but since even 10% is breathable at your oxygen stop, it's definitely not the primary justification.

I agree. But OP did say aside from being able to plug in offboard dil

 

[211ratsbud]

Thanks guys, I don't have cave experience so that kinda clears things up. while aware of it as a possibility I didn't consider the richer gas onboard as a suitable idea.

I'm diving into the deeper end of the freshwater pool, so I thought I should understand the difference better.

 

[tbone1004]

Thanks guys, I don't have cave experience so that kinda clears things up. while aware of it as a possibility I didn't consider the richer gas onboard as a suitable idea.

I'm diving into the deeper end of the freshwater pool, so I thought I should understand the difference better.

Unfortunately if you don't have a manufacturered unit it's impossible to find coaching with regard to some aspects.

for open water diving your deco profiles probably won't be long enough to warrant plugging in offboard gas though I do personally like the habit reinforcement of doing full gas switches and just plugging in vs. getting on the second stage.

 

[211ratsbud]

Thanks Tom, currently I only have a push button adv on a splitter with the bov hose, and a qc6 on the bottom feeding it like a fathom. ( The adv is isolatable in my config)

I will keep doing this as it's been no issue and not particularly cumbersome. I'll adjust the supply hose length so it can be tidied up (Has bov now as well)

 

[RedSix]

it doesn't allow offboard dil to be plumbed in

Actually this is not completly true. Offboard Dil can be plugged using the (O2) MAV.

The Fathom config also allows you to use a different drive gas than your OC bailout. A ginnie springs dive is a great example. Ideal dil would be 21/35, but that's not a great OC bailout or SCR gas. So with the fathom config, you can drive the unit with a 21/35 stage and still have 32% on your back for bailout or to run SCR if you need to.

This can be done with the GUE JJ as well, using the (O2) MAV.

A quite common "modification" (at least in europe) of the GUE hose routing includes a switch block. But this makes the routing way more complex than the standard routing.