Suggested CCR Reading

[KenGordon]

One thing I've gleaned from all the threads here is that my first unit should probably be a used one

I bought my first/only unit new. At the time I would have had less than no idea what to look for in a used unit. In my opinion you should buy through an instructor able to train you on the unit and stand behind any issues it has. I get the impression that people who give up often sell via their instructor.

I did consider buying a cheap ADP classic at first but like old cars you risk spending more time messing about keeping the thing alive than enjoying it. I want to go diving, the JJ is a bit of a toy as 90% of my dives could be done with a twinset etc, but I don’t want to be losing dives to the toy factor.

I have had three issues with my JJ. The ADV isolator failed, fixed by buying an identical one from ADP with three days to spare. I lost a day of diving when a hamfisted skipper crushed by HUD on a liveaboard, replaced via Narked by the time I got home, and lastly I lost a day when the Shearwater bits in the head died leaving me without a HUD.

There are a couple of things that could be better, you have to take care how you handle the head once it is removed (to dry the cells) to avoid getting muck on the orings, silt and rust can also get in awkward places where the head slots into the body. However there are no fatal o rings to leave out when just refilling the scrubber, or random wires that need pushing out of the way or the co2 can get past or really anything nasty.

I had two main reasons vs the ADP, one ones the Petrel vs the nasty old mono display, the other was it being in a big metal tube vs a big fragile plastic box.

If you bought a new JJ in Europe and hated it you could probably sell it at only a small loss. They are about 7k Euro plus tax new and I am sure there would be a queue for a 30 hour 6 month old one at 7k (tax inclusive). A good rule of thumb for dive gear, especially buying new, is to buy the kit the DIR wannabes regard as cool. This means that there will be an endless stream of people willing to buy it should it be surplus to your requirement. I did not buy the JJ on that basis but now it turns out I was lucky with the GUE adoption.

People say “buy what people around you dive”. While I often see them on boats I don’t have any regular buddies with a rebreather. The support from Narked, the factory etc is such that that doesn’t matter. Maybe they are some brands that require community support. As I said earlier the CE testing keeps many of the US local brands away, I have never seen most of those units.

 

[rjack321]

Given that I see almost no used JJ's for sale, should I infer that JJ owners are happy with their units? Clearly KenGordon does, per his post above. I do see the occasional used Meg for sale, but maybe there are just more of them out there? Mel teaches on both the Meg and JJ, so I'm covered either way on that count. One thing I've gleaned from all the threads here is that my first unit should probably be a used one

Mel would not be my go to instructor
If you want a Meg take a class from Leon himself.
If you want a JJ I would look at some of the FL instructors
As far as I can tell, Mel doesn't actually dive either of those units (despite being an instructor). I guess if you wanted a Revo you might go with her.

 

[rsingler]

JJ in FL?
Call or email Dan Dawson
Horizon Divers, Key Largo, FL
dan@horizondivers.com
Superb class. Small class. Long days. Very thorough.
We booked over 10 hours of ocean time in addition to classroom unit building and theory.
Preparatory work thru TDI was pretty mickey mouse if you've read up beforehand. Whatever.
I couldn't be happier, and am building hours to get back for CCR deco with him this winter.

 

[MrBlenny]

JJ in FL?
Call or email Dan Dawson
Horizon Divers, Key Largo, FL
dan@horizondivers.com
Superb class. Small class. Long days. Very thorough.
We booked over 10 hours of ocean time in addition to classroom unit building and theory.
Preparatory work thru TDI was pretty mickey mouse if you've read up beforehand. Whatever.
I couldn't be happier, and am building hours to get back for CCR deco with him this winter.

Thanks for the info, a skilled, organized instructor goes a long ways.

Also, since it sounds like you are actively diving a JJ, how is the WOB when inverted? I get into rather odd positions sometimes when taking photos.

 

[rsingler]

A simple head down inversion is not that much different on the JJ than standard diving position. The portion of the CL's that drapes over the shoulder will empty and the main portions of the CL compartments will be now slightly above your lung centroid. Just as it is when diving normally. Of course, your loop mouthpiece will now be lowest which will increase inspiratory effort.
But "odd positions" can be quite different. Inverted but looking slightly up (like under a ledge) puts your counterlungs below you, and you may get some chipmunk cheeks depending upon how full you keep them. More important this now puts your cells lowest, and susceptible to water condensate draining onto the cell face.
CCR cell location should be one of the things you look at as you think about your photo diving in odd positions.

 

[MrBlenny]

Mel would not be my go to instructor
If you want a Meg take a class from Leon himself.
If you want a JJ I would look at some of the FL instructors
As far as I can tell, Mel doesn't actually dive either of those units (despite being an instructor). I guess if you wanted a Revo you might go with her.

Fair point, I'm not actively looking at the Revo at this point in time (I did see a Meg sitting in Mel's garage, but she opted to a different unit during my AN/DP class with her.) Have you had personal interaction/training with Leon, or just by reputation? ISC is only 90 minutes north of me, which is one reason I am considering the Meg. I've also read that they breath well in head-down orientations, which is important to me for photography.

 

[MrBlenny]

A simple head down inversion is not that much different on the JJ than standard diving position. The portion of the CL's that drapes over the shoulder will empty and the main portions of the CL compartments will be now slightly above your lung centroid. Just as it is when diving normally. Of course, your loop mouthpiece will now be lowest which will increase inspiratory effort.
But "odd positions" can be quite different. Inverted but looking slightly up (like under a ledge) puts your counterlungs below you, and you may get some chipmunk cheeks depending upon how full you keep them. More important this now puts your cells lowest, and susceptible to water condensate draining onto the cell face.
CCR cell location should be one of the things you look at as you think about your photo diving in odd positions.

Great info. My most common, non-trimmed position is a slight head-down, and on rare occasions completely inverted with feet up, but virtually never on my back (not for photography, anyway.)

 

[rsingler]

Well, then the JJ will be great, because that brings more of the shoulder portion lower. If you keep your counterlungs slightly fuller, breathing is almost effortless. And cells will stay at the top of the tube (but they're well engineered anyway re: position).
On your back, for example, you can see that sensor #2 will then face uppermost, and you can see on your handset which cell suddenly changes its reading if it's face is flooded. The other two cells remain sideways to condensate, even on your back.

In contrast, the Meg head has the cells facing down, which means up when you're inverted. The Meg guys can say whether that's a risk for trapping water when inverted. On your back shouldn't affect things.

 

[evandroairton]

The JJ looks like an inspiration at first sight.
That's an impression i've had, the head configuration is even like my classic AV1 HEAD (image from AV site)
Am i right, or Just an impression?

 

[rjack321]

Fair point, I'm not actively looking at the Revo at this point in time (I did see a Meg sitting in Mel's garage, but she opted to a different unit during my AN/DP class with her.) Have you had personal interaction/training with Leon, or just by reputation? ISC is only 90 minutes north of me, which is one reason I am considering the Meg. I've also read that they breath well in head-down orientations, which is important to me for photography.

I've been diving with Leon a couple times but not in an instructor-student relationship. I've also been down to ISC a few times. His MOD1 exams (which should be used in any approved Meg course I think) were really good.

The Meg is a solid unit and I personally like the design qualities and modularity a little better than the JJ.