Just got my new JJ in this morning!!!

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Take care of your HUD!!!!
Here is my el cheapo HUD protector.
20200913_123506.jpg

A 10ml plastic syringe barrel is the perfect diameter for the HUD wrapped in a single layer of paper towel. A rubber band in a figure of eight grabs both the syringe and the cable so it doesn't slip out of place. Seems to protect my HUD from getting banged about, especially when it pops out of the holder on the DSV.
 
@rsingler I'm stealing that. Awesome HUD protector!

@doctormike I definitely use a pre-flight list. I use the one from the manual for set up before getting on the boat and the START plan we used in my class that I have written in my wetnotes. Though, I really want to get that typed and printed on a card that will be better than my terrible handwriting. Making progress, but still being safe in the mean time.
I'm definitely going to start working on trim weight. I think wood dowel rods and these will get me started.

https://www.amazon.com/END-GAME-Fis...64&sprefix=lead+rod,aps,182&sr=8-7&th=1&psc=1
 
Here is my el cheapo HUD protector.

Sorry, Rob... My HUD protector is much better. It keeps it EXTREMELY safe, so that if my NERD fails, it will be ready to go...

pellican.jpg
 
@rsingler

@doctormike I definitely use a pre-flight list. I use the one from the manual for set up before getting on the boat and the START plan we used in my class that I have written in my wetnotes. Though, I really want to get that typed and printed on a card that will be better than my terrible handwriting. Making progress, but still being safe in the mean time.
I'm definitely going to start working on trim weight. I think wood dowel rods and these will get me started.

Hooray! But read that article that I wrote. I feel very strongly about this stuff.

Think about the difference between having it on a card or in your note book, and having it stuck on your controller (or somewhere else) as a label.

The label will ALWAYS be there, and it doesn't occupy one of your two hands to use like a card does. All you have to do is glance at it. You don't want to be clutching something while you are dealing with your valves, MAVs, ADV, BC, etc..

You don't have to remember to bring it. You don't have to stow it away at the end of the check. Or if you don't want to deal with putting it away in the time between your pre-flight check and splashing (which should be a very short time), it doesn't have to be clipped off to your harness as an entanglement point.

Also, the build checklist and the pre-splash checklist are completely different things - for some reason, those always seem to get conflated in these discussions.
 
Hooray! But read that article that I wrote. I feel very strongly about this stuff.

Think about the difference between having it on a card or in your note book, and having it stuck on your controller (or somewhere else) as a label.

The label will ALWAYS be there, and it doesn't occupy one of your two hands to use like a card does. All you have to do is glance at it. You don't want to be clutching something while you are dealing with your valves, MAVs, ADV, BC, etc..

You don't have to remember to bring it. You don't have to stow it away at the end of the check. Or if you don't want to deal with putting it away in the time between your pre-flight check and splashing (which should be a very short time), it doesn't have to be clipped off to your harness as an entanglement point.

Also, the build checklist and the pre-splash checklist are completely different things - for some reason, those always seem to get conflated in these discussions.

THIS! (Personally I follow the GUE Checklist for building (Stuck to side of rebreather), and CHAOS (stuck to my controller)

Just this weekend the linearity check caught a beginning cell failure one day, and a pinched o-ring on the oxygen banjo the next day. New cell, new o-ring. No dives lost. (Until my P-valve broke. Really happy we had sun. And someone had to skipper the boat)

Images shamelessly stolen on the interwebs. (But, educated guess is that they are taken by Adam Hanlon from WetPixel. I know he might sell some of these stickers from time to time)
200213-ahanlon-2738.jpg

I prefer to keep a few old stickers on here as well. That way I have a history of performance, and can track changes if any.

200213-ahanlon-2740-768x1024.jpg
200213-ahanlon-2743.jpg
 
THIS! (Personally I follow the GUE Checklist for building (Stuck to side of rebreather), and CHAOS (stuck to my controller)
Yup, those checklists are really well thought out. I use all three. I've had quite a few friends mention how much they like that I have everything in simple form on my unit to avoid forgetting a step.
 
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?
Well, even though Scuba Client has gotten himself banned, I can now shed some light on this issue. Just completed Advanced Wreck with Dan Dawson at Horizon Divers in Key Largo, and between the course and fun dives after, we spent 8 dives down in the bowels of the Spiegel Grove between 120 and 137 feet in the engine rooms and pump room. Awesome instruction!!
Going headfirst down the narrow trunks two decks in a row (120+ feet), I can confirm a marked increase in JJ-CCR WOB if your counterlungs are at min volume, or even "ideal volume".
Screenshot_20210817-214815_Video Player.jpg

The over-the-shoulder component of the counterlung is where the ADV is situated, and the loop inhalation hose is past that. So if your C/L's are in a low-vol state, most of the gas is in the base of the sacs above you. With the C/L's flattened in between the gas pocket and your loop, inspiratory effort can be a little frightening, especially if you're space constrained and can't level out for ease of breathing. I almost shifted to my necklaced B/O in the trunk...
I don't yet have enough experience to say for certain, but the next time I'm there, my plan is to dump some of the wing gas I added with wetsuit compression, and shift it to carry my C/Ls fuller as I approach the trunk. Once neutral at the top of the trunk, I'll see if adding a bit of gas to the counterlung with the MAV to maintain buoyancy over the next 20 feet of descent makes it easier to go vertically head down. I do know I was adding gas via the MAV when things got uncomfortable, but don't yet have a feel for whether I can maintain neutral buoyancy that way in the descent. And with a 2 1/2' wide trunk, I'm glad I didn't have to reach up to my shoulder to trigger the ADV, and could instead just hit the MAV near my lower D-ring with my right hand while running line with my left. Some folks with the older JJ's aren't impressed with the need for a dil MAV, but inside the wreck, I kept my ADV shut off and used the MAV for fine tuning. Head down in that constrained space, it was even more useful.
Frankly, I don't know how JJ-CCR passed CE in that position, unless buoyancy wasn't a concern, and WOB was within standards solely as a result of minimal counterlung vs. lung centroid position difference, with no added resistive component due to a collapsed min volume counterlung. They may have gamed that one, I'm thinking.
 
Frankly, I don't know how JJ-CCR passed CE in that position, unless buoyancy wasn't a concern, and WOB was within standards solely as a result of minimal counterlung vs. lung centroid position difference, with no added resistive component due to a collapsed min volume counterlung. They may have gamed that one, I'm thinking.
JJ-CCR appears to have been tested for WOB at a +74' Pitch, which is a tad different to the traditional horizontal or vertical; making direct comparison harder but it appears pretty good.

However, what you are referring to is its hydrostatic performance, which is a completely different beast. And as ones dive planning would have identified, the JJ-CCR appears outside the EN14143 criteria for hydrostatics when headup, inverted through to headdown per Figure 3-13; with the ADV open. https://jj-ccr.com/wp-content/uploads/2018/06/QQ-14-01561-JJ-CCR-June-2014-V1.pdf

No mention is made of the inclusion of any wing BCD being fitted to the unit undergoing testing and QinetiQ have a habit of testing to EN14143 without one fitted. So if you were diving with one, it may have also had an impact on the CLs, that you'd have to take a guess at factoring in.
 
https://www.shearwater.com/products/teric/

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