It finally happened - my CCR tried to kill me

[stuartv]

How many hours are you up to on the loop?

95 hours on the loop now. I have been keenly aware that the statistics say that the time from 50 - 100 hours is the most dangerous time for a CCR diver. I have been actively working with my rEvo instructor for a year now to get my MOD2 training scheduled. Basically, COVID has screwed me so far on that plan, but I'm still working on it. I told her that one of my goals in getting the next training is to learn new stuff but also to review and reinforce all the stuff I was supposed to have learned in MOD1. It has been 2 years now, since my 1 week MOD1 class. I frequently wonder about what I'm doing and if I'm still doing everything correctly, or if I am experiencing any memory fade and "creep" in what I'm doing.

This incident that I reported to you all have definitely served to reinforce my desire to get the next level of training - so that I can also get that review and check on the basics.

thanks Stuart - another indicator of the lid not closing properly is the threaded rod not coming through far enough for the wing nut thingy to fasten down - my regular check is the battery box stopping it from seating properly

My instructor instilled in me to feel under the cover (no jokes please) to make sure its sitting flat. I also dont add cylinders until after installing the cover. I make sure the battery box is free to wiggle. Its really the battery box that screws up the cover going on. Might be a cool mod to mount the box permanently

To be clear, the lid was on properly. I THINK the problem was that the O2 cylinder was pressing on the side of it, after it was seated properly.

 

[wedivebc]

A planned deco dive on ccr definitely requires open circuit bailout deco gas

I can't believe any CCR diver these days does not know this instinctively.

 

[stuartv]

To all of you that have taken the time to post in this thread, I thank you. Both for your contribution and for keeping things so civil.

I felt like I learned a lot from what happened. I feel like I have learned even more from this discussion. I will definitely be doing some things differently in the future.

 

[wedivebc]

To all of you that have taken the time to post in this thread, I thank you. Both for your contribution and for keeping things so civil.

I felt like I learned a lot from what happened. I feel like I have learned even more from this discussion. I will definitely be doing some things differently in the future.

Also thanks for the life lesson. Glad you're OK.

 

[Wibble]

It has been 2 years now, since my 1 week MOD1 class. I frequently wonder about what I'm doing and if I'm still doing everything correctly, or if I am experiencing any memory fade and "creep" in what I'm doing.

Just a thought; have a coaching day with your instructor well in advance of your MOD2. It's amazing how much they can pick up and help you with on just a while in the water. Well worth the money.

 

[stuartv]

Just a thought; have a coaching day with your instructor well in advance of your MOD2. It's amazing how much they can pick up and help you with on just a while in the water. Well worth the money.

That would be great. Unfortunately, we live about 1100 miles apart. And, the reason we haven't done the class yet is because of not being able to fit it into her schedule at all. I don't know that getting together for 1 or 2 days will work out any better. If I could get together with her for 2 days, I'd probably try to make that be the first 2 days of the class and then meet again for the rest as soon after as possible.

 

[kensuf]

Are you currently still in Pompano? Maybe you should hook up with Alec Hutchinson for a day or two, he lives and teaches in Boca and is a Revo instructor and is a guy I would send my children to (if I had children) for revo training.

 

[Jwoobs]

My instructor instilled in me to feel under the cover (no jokes please) to make sure its sitting flat. I also dont add cylinders until after installing the cover. I make sure the battery box is free to wiggle. Its really the battery box that screws up the cover going on. Might be a cool mod to mount the box permanently

Not that I am a Human Factors convert (the book about put me to sleep, I started just reading anecdotes for the last half), but sounds like the rEvo might just have a bad design. If it can be assembled incorrectly, it eventually will. Even worse is that this particular failure seems to not be checked with a positive test or undetectable even with a positive test.

 

[rddvet]

So your rebreather gave you an indication that things weren't right so you bailed out. Good job. But then you went back on the loop? I don't think it was your rebreather trying to kill you at all.

I don't necessarily agree with this. I've got no issue recognizing a problem bailing out, mentally going through the list of causes, and if I feel it safe attempting to go back on the loop.

I can't believe any CCR diver these days does not know this instinctively.

This I fully agree with. If you're doing a deco dive either OC or CCR, you need a deco gas. My wife and I will sometimes cheat and only bring 1 bottle of oxygen for the two of us when on ccr (which includes a qc6 so it can be plumbed in) and half the time I feel guilty being that lazy so we have since stopped that practice.

 

[KDAD]

incorrect. When you pull a negative you are creating a partial vacuum which reduces the ppO2 in the loop. When you blow a positive you are creating a slightly high pressure environment in the loop. If you both after an O2 flush, you'll see the ppO2 go from 1.0 down to .9x during the negative and if it holds a good negative it won't rise back to 1.0. When you perform the positive it will go up to 1.0x and if it holds a positive it will stay there, if not it will fall back to 1.0
They can function as ambient pressure sensors when in a fixed fO2. The Liberty has actual ambient pressure sensors in the head and it uses those for its positive and negative checks, but the good CCR instructors teach you to use the O2 sensors to check whether your unit is behaving for those two.

Agree. I should have said that once the unit is put under either a positive or negative pressure the sensors can then be monitored for changes which could indicate a leak as the pressure changes.