Bonaire accident issues Close Call

[gfaith]

Such catastrophic case integrity failures often will show up as a problem when the user does a vacuum test well before it lets the entire ocean in.

Nice reminder. I can not say that I have been doing that in my pre-dive routine before opening the valve..

 

[beaverdivers]

I believe a positive point to be derived from this thread is that a negative pressure test or as awap described a "vacuum test" should be an important step in a pre-dive check.

It may or may not have averted your buddies problem.

 

[gcarter]

Nice reminder. I can not say that I have been doing that in my pre-dive routine before opening the valve..

I do that regularly. My son had the exhaust valve on a second stage fold over in current. The case design was too tight to allow it to flip back on its own, and the exhaust port was too small to allow use of a finger to flip it back.

Breathing it resulted in a mouthful of water. Both my primary and secondary get dry tested before pressurizing to check that all is as it should be.

 

[jseyfert3]

So, you are saying an older diamond is less reliable than a newer diamond?

Actually, yes. Diamond is what's called a metastable allotrope of carbon (I had to look up that name), where allotrope means form (diamond, graphite, carbon nanotube, etc), and metastable means it's pretty stable but doesn't prefer that form (steel is metastable and prefers to separate into iron and carbon). The most stable form of carbon is graphite, and diamond will slowly turn into graphite, although that will take millions or billions of years at standard conditions.

 

[RyanT]

Hey thook, so when you said you hooked it up at the dive shop and it made a horrible sound, was this after the incident? Either way, your dive shop should have been able to disassemble it on the spot to see what was happening. It sounds like you may have a bad shop/technician. Giffenk provided a list of the the most likely culprits, and if it was making a sound upon hooking it up, I might guess a hole in the diaphragm.

Regardless, again here's the value of you sharing your story. My current dive buddy is a new diver and we frequently discuss emergency scenarios and how to handle them. Over lunch I was telling her about what happened to you guys (this is not a scenario we had discussed before). She said just hearing the story almost made her want to panic. We discussed what she should do first in that situation and then further discussed our buddy protocols and U/W teamwork. Not to say that our planning would guarantee a successful outcome in that situation, but always, the more you know, the better off you are.

 

[Lorenzoid]

I believe a positive point to be derived from this thread is that a negative pressure test or as awap described a "vacuum test" should be an important step in a pre-dive check.

So let me make sure I understand: This pre-dive test would involve inhaling through the mouthpiece before turning the tank valve on, and making sure no air is leaking through a damaged exhaust valve, diaphragm, or the case? (Then, turn the tank valve on and proceed with the more typical pre-dive check of taking 2-3 breaths through each second stage.) Is that what we're talking about here?

I have had an exhaust valve flap fold under once in a current, but it didn't result in a lungful of water; just a manageable amount of water leakage into the reg.

 

[redacted]

I have had an exhaust valve flap fold under once in a current, but it didn't result in a lungful of water; just a manageable amount of water leakage into the reg.

One very important result of this test is it allows you to detect small problems before they become big problems. All regs let a little water in as the exhaust valve operates. It is pretty hard to avoid. But they also Expell those small amounts of water each time you exhale. So, a pinhole in a diaphragm, damaged sealing surface on an exhaust valve, defective case o-ring, or even a crack in a plastic case may not be apparent during a dive until the defect becomes quite severe.

Regulators can really be quite reliable if the effort is made to detect and correct small faults before they become a big problem. There really are very few failure modes that go from everything is fine to I can't breath in an instant, other than service errors.

 

[cephalopod2]

Thook I just wanted to thank you and your wife again for sharing your experience and allowing us to reflect and learn. I am so glad she is OK.

 

[Tom Black]

Such catastrophic case integrity failures often will show up as a problem when the user does a vacuum test well before it lets the entire ocean in.

This, remember this, write it down on a note and put it somewhere you see it often, so you don't forget it. You really have to check everything carefully to avoid nasty situations. Anyway, I am really happy that nothing serious happened and she is okay.

 

[Thook]

Hey thook, so when you said you hooked it up at the dive shop and it made a horrible sound, was this after the incident? Either way, your dive shop should have been able to disassemble it on the spot to see what was happening. It sounds like you may have a bad shop/technician. Giffenk provided a list of the the most likely culprits, and if it was making a sound upon hooking it up, I might guess a hole in the diaphragm.

Regardless, again here's the value of you sharing your story. My current dive buddy is a new diver and we frequently discuss emergency scenarios and how to handle them. Over lunch I was telling her about what happened to you guys (this is not a scenario we had discussed before). She said just hearing the story almost made her want to panic. We discussed what she should do first in that situation and then further discussed our buddy protocols and U/W teamwork. Not to say that our planning would guarantee a successful outcome in that situation, but always, the more you know, the better off you are.

Yes Ryan it was post event..I did not have them disect the regulator at that point as they are not my dive shop and I will have that done later, but very good point with your new dive buddy.. anytime we can learn from others misfortunes is a good opportunity.