Just got my new JJ in this morning!!!

[Grantt]

Hey guys, just like the title says. Wooo!!!

So I did my mod 1 course in Feb 2020 and just got settled into being land based again here in Florida.
I am going through the manual and my class material. Going to get in the pool to test everything out before hitting the OW.
Anyone have any suggestions for stuff I may have forgotten in the past year?
I'd appreciate any tips or anything to be mindful of. Just want to cover my bases.
Thanks for the feedback. Cheers!

 

[Heat Miser]

Hey guys, just like the title says. Wooo!!!

Anyone have any suggestions for stuff I may have forgotten in the past year?
Thanks for the feedback. Cheers!

1. Allways dive a CCR with a buddy. If your going to test it in the pool make certain someone is watching you.

 

[rsingler]

Congratulations!
Welcome to the JJ club! Great machine!
Never skip your valve check before you build your loop. Had two valve malfunctions with those thin mushrooms, including one that arrived that way from the factory. They're great, but delicate. If you disconnect your DSV from the hose for any reason, the two orings that seal it to the hose are just lying in a shallow land and can shift position (ask me how I know). They're not trapped like the ones on the hose ends that attach to the head and t-pieces.

Consider building your own checklist. The JJ one is complete but may not match how your instructor had you build your machine. Do you have an IP gauge to keep an eye on your O2 reg?

Have a ball!
As you tweak your trim, keep in mind that you'll have differing trim (but the same buoyancy) with full lungs/empty counterlungs vs. empty lungs and full counterlungs. My feet drop slowly on full exhalation as the shoulder portion of the CL puffs up. I can keep them up with the counterlungs emptier because my own lung centroid is more south.

In a drysuit I'm fine, but in 3mm Florida neoprene I have to add two 2#'s to the tops of the tanks to trim out. Bought small cam bands to do that.

Enjoy!

 

[Grantt]

@rsingler
I remember the DSV is disassemble only if necessary. I appreciate the note on that.
We had a check list in the equipment room in my class, I will reach out to my instructor to see if any changes were made or if he recommends any.
Yes, sir. I do have an IP gauge.
I didn't use any weight in the class with one steel/one AL both 3L tanks. I only have steel 2Ls now, so I will have to check that out and play with the trim.

I am generally only diving on the weekends, can I store the partially used scrubber can in a dry bag from one weekend to the next?

 

[rsingler]

I am generally only diving on the weekends, can I store the partially used scrubber can in a dry bag from one weekend to the next?

That is argued. I don't have a definitive answer. Since I try to get in 2hrs of diving in a day, I might use it again the next day. But I got burned doing that when I missed an unexpected second deep dive because I'd used up the second two hours on the second morning and couldn't get it repacked before the boat left Sunday afternoon.
And then there are divers who will use it past the listed 4hr life.
But a week apart? Are you definitely only going to use it for two hours the next week? Do you have sorb to repack if you need to dive again? Was it tightly sealed in between?
Lots of questions. Me, I don't go past one weekend to the next. That is $10 more expensive. Others do.

 

[Scuba Client]

Hey guys, just like the title says. Wooo!!!

So I did my mod 1 course in Feb 2020 and just got settled into being land based again here in Florida.
I am going through the manual and my class material. Going to get in the pool to test everything out before hitting the OW.
Anyone have any suggestions for stuff I may have forgotten in the past year?
I'd appreciate any tips or anything to be mindful of. Just want to cover my bases.
Thanks for the feedback. Cheers!

Dive with someone who has a JJ and knows it like the back of his/her hand.

 

[Scuba Client]

Congratulations!
Welcome to the JJ club! Great machine!
Never skip your valve check before you build your loop. Had two valve malfunctions with those thin mushrooms, including one that arrived that way from the factory. They're great, but delicate. If you disconnect your DSV from the hose for any reason, the two orings that seal it to the hose are just lying in a shallow land and can shift position (ask me how I know). They're not trapped like the ones on the hose ends that attach to the head and t-pieces.

Consider building your own checklist. The JJ one is complete but may not match how your instructor had you build your machine. Do you have an IP gauge to keep an eye on your O2 reg?

Have a ball!
As you tweak your trim, keep in mind that you'll have differing trim (but the same buoyancy) with full lungs/empty counterlungs vs. empty lungs and full counterlungs. My feet drop slowly on full exhalation as the shoulder portion of the CL puffs up. I can keep them up with the counterlungs emptier because my own lung centroid is more south.

In a drysuit I'm fine, but in 3mm Florida neoprene I have to add two 2#'s to the tops of the tanks to trim out. Bought small cam bands to do that.

Enjoy!

Thanks for providing the flaws on the JJ.

 

[Scuba Client]

@rsingler
I remember the DSV is disassemble only if necessary. I appreciate the note on that.
We had a check list in the equipment room in my class, I will reach out to my instructor to see if any changes were made or if he recommends any.
Yes, sir. I do have an IP gauge.
I didn't use any weight in the class with one steel/one AL both 3L tanks. I only have steel 2Ls now, so I will have to check that out and play with the trim.

I am generally only diving on the weekends, can I store the partially used scrubber can in a dry bag from one weekend to the next?

The questions you are asking tells me you went in too early for CCR training. I see a lot of divers with no real technical dive experience going straight into CCR training. Their trim and fin technique is poor.

 

[rsingler]

Thanks for providing the flaws on the JJ.

Well, since one failed valve check was operator error (me), and the other was just too much goop when the halves of the DSV were first assembled, holding one leaflet off the valve face, I haven't lost confidence in my toy. It's built like a tank and I've figured out most of the trim tricks. The electronics are flawless; the HUD is standard, and the WOB is impressive. Diving the Spiegel in current has been a bit sporty at times, and if a 70 y/o anesthesiologist can manage without complaining about the circuit/breathing resistance, it's probably as good as its specs.
When I reach a hundred hours I'll report back with any real complaints. Right now, I'd still call myself a newbie.

 

[Scuba Client]

Well, since one failed valve check was operator error (me), and the other was just too much goop when the halves of the DSV were first assembled, holding one leaflet off the valve face, I haven't lost confidence in my toy. It's built like a tank and I've figured out most of the trim tricks. The electronics are flawless; the HUD is standard, and the WOB is impressive. Diving the Spiegel in current has been a bit sporty at times, and if a 70 y/o anesthesiologist can manage without complaining about the circuit/breathing resistance, it's probably as good as its specs.
When I reach a hundred hours I'll report back with any real complaints. Right now, I'd still call myself a newbie.

Thanks for your reply and reporting my comments so they're deleted. I welcome your opinions without prejudice, something most contributors fail to do. My top CCRs are Megaladon, JJ and AP. I've heard from JJ users that when diving head down in a mine shaft that the WOB is noticeable. Perhaps you can add credence?