JJ CCR Scrubber Radial? vs Axial

[Wibble]

how do you define multi hour?

deep? how deep is deep? 80m? more? goal is to get to 110m for a wreck im after.

There’s so much more to this than a simple answer can give.

Water temperature for a start; scrubbers last longer in warmer water. What’s the bottom time — which will be constrained by your bailout plan? Who’s in the team? Can you stage bailouts? What support is there? Dive profiles?

You’ve an awful lot of diving to do on your JJ in order to dive that wreck. Not least the MOD1, MOD2 and MOD3 courses. As you gain experience you will be able to answer that question. Radial vs axial is a tiny part of the planning.

Whilst a 110m/400ft wreck is a good goal, it’s a challenging goal which will take years of preparation and practice to plan and execute safely. Something like three years and 300 appropriate quality hours on the unit.

 

[LanceRiley]

to

There’s so much more to this than a simple answer can give.

Water temperature for a start. What’s the bottom time — which will be constrained by your bailout plan? Who’s in the team? Can you stage bailouts?

You’ve an awful lot of diving to do on your JJ in order to dive that wreck. Not least MOD1, MOD2 and MOD3. As you gain experience you will be able to answer that question. Radial vs axial is a tiny part of the planning.

Whilst a 110m/400ft wreck is a good goal, it’s a goal which will take years of preparation and practice to plan and execute safely.

to be honest... i haven't gotten the unit yet. planning to do CCR next year budget permitting
yes im aware... Mod1 mod2 mod3. this isn't a 1 year proj.

planning to be at that wreck in 2 years time.

Just wanted to make sure i got the right scrubber and not have to buy another scrubber midway.

thanks for the insight

 

[Wibble]

to

to be honest... i haven't gotten the unit yet. planning to do CCR next year budget permitting
yes im aware... Mod1 mod2 mod3. this isn't a 1 year proj.

planning to be at that wreck in 2 years time.

Just wanted to make sure i got the right scrubber and not have to buy another scrubber midway.

thanks for the insight

The scrubber can be bought at any time, pretty cheap but comes with its own issues, such as using 50% more 'sorb than axial.

The main "tip" is to get the hours in and gradually work down to the target. There’s a lot of skills to develop for the three "MOD" courses.

Oh, and deep diving is boring! Hours hanging around doing sod all on deco.

 

[boriss]

to

to be honest... i haven't gotten the unit yet. planning to do CCR next year budget permitting
yes im aware... Mod1 mod2 mod3. this isn't a 1 year proj.

planning to be at that wreck in 2 years time.

Just wanted to make sure i got the right scrubber and not have to buy another scrubber midway.

thanks for the insight

The amount you're going to spend on the unit, training, consumables, maintenance, support and dives themselves will be pretty staggering. The choice of scrubber at this point will be a wash. In fact, if you go with a smaller axial scrubber up front, you'll probably save enough $$ on sorb cost alone to pay for the radial scrubber in the future. Maybe not, but type of scrubber doesn't matter at this point. A stock JJ scrubber will handle a dive to 100m no problems. There are many other things to overthink in the meantime

 

[LanceRiley]

ok noted on this scrubber is easy to buy...
work on the hours.

 

[LanceRiley]

The amount you're going to spend on the unit, training, consumables, maintenance, support and dives themselves will be pretty staggering. The choice of scrubber at this point will be a wash. In fact, if you go with a smaller axial scrubber up front, you'll probably save enough $$ on sorb cost alone to pay for the radial scrubber in the future. Maybe not, but type of scrubber doesn't matter at this point. A stock JJ scrubber will handle a dive to 100m no problems. There are many other things to overthink in the meantime

yes it is mighty staggering cost. but now that you mention that a small axial scrubber will get me to 100m . is assuring... it's just a target dive. doesn't mean i'll be diving 100m every time.. probably 50-60m where most of the dives are in my area.

 

[Wibble]

@LanceRiley - When do you think you'll be doing your MOD1? A huge number of your questions and thoughts will be answered during that.

Afterwards it's a slow progression working on your skills and adding new things.

The biggest tip someone gave me was "it's the ascents that count". It's so different from OC as so much is going on with the unit. Add to that some lightweight deco, then more deco, it gets fun. Eventually your buoyancy control will return.

Then you'll have your big moment when the unit tries to kill you because of complacency. That's fun and a massive learning opportunity!

 

[Geo7]

I also seem to remember "rumors" of a difference between radial and axial scrubbers in how rapid the CO2 increase is in a scrubber near the end of its capacity. The theory was that in an axial scrubber a more narrow active zone travels through it linearly as it is used (that's what the AP tempstick measures via temperature).

In contrast, a typical radial scrubber has a narrow overall bed depth, and the entire scrubber is supposed to be used as the active zone throughout the duration. Not sure how to best explain that concept. CO2 at the end of the duration of the radial scrubber is supposed to increase more gradually as a result. An exception are the Biomarine Mk15.5 scrubbers that are axial but have dimensions that achieve the same effect as described above.

And I wrote "rumors" and "theory" above, as I have not seen actual data to confirm this. Maybe in John Clarks new book thatI'll read over the holidays. Not sure the difference matters, but it's interesting and I'd appreciate if anyone has more info/thoughts...

 

[rjack321]

I also seem to remember "rumors" of a difference between radial and axial scrubbers in how rapid the CO2 increase is in a scrubber near the end of its capacity. The theory was that in an axial scrubber a more narrow active zone travels through it linearly as it is used (that's what the AP tempstick measures via temperature).

In contrast, a typical radial scrubber has a narrow overall bed depth, and the entire scrubber is supposed to be used as the active zone throughout the duration. Not sure how to best explain that concept. CO2 at the end of the duration of the radial scrubber is supposed to increase more gradually as a result. An exception are the Biomarine Mk15.5 scrubbers that are axial but have dimensions that achieve the same effect as described above.

And I wrote "rumors" and "theory" above, as I have not seen actual data to confirm this. Maybe in John Clarks new book thatI'll read over the holidays. Not sure the difference matters, but it's interesting and I'd appreciate if anyone has more info/thoughts...

The other way around.
If you "unwrap" a radial scrubber you end up with a sorb bed which has a large surface area and a comparatively shallow depth. An axial scrubber has a smaller surface area and a much greater sorb bed depth.

The axial scrubber is consumed in a cone like shape due to the shape, temperature and flow dynamics of the walls. The radial scrubber is consumed more evenly - although I am not sure "linearly" is really the correct adjective there. That's why gram for gram radials are generally considered 'more efficient'. Both have a rapid rise in CO2 from zero to >0.5% as breakthrough occurs, I would definitely not choose one or the other based on it's hypothetical end of life characteristics

If I were the OP I would just get the standard JJ axial scrubber. It's easier to pack, less likely to channel, and more than adequate to learn and grow on for years. Someday, years from now if you want a new toy (or just a spare scrubber) the OP can get the radial.

 

[rsingler]

AFAIK, JJ will not even sell you a radial XRC can when you first buy. You need at least Mod1 before. I asked when I was first starting. Glad I didn't. Lots to learn between here and there. And don't discount the saved sorb cost. We all wasted a lot of sorb in training, discarding half used scrubbers before a bigger pair of dives the next day.