Use a gag strap?

[stuartv]

Thank you for the detailed reply. Unfortunately plenty of very experienced CCR Divers and Instructors have been victims of human error. It affects divers, surgeons, pilots etc. Thats why they used the word 'should' when they told you above there was no need for BOV. The rEvo dual scrubber can be overcome. I have a rEvo and I once managed to overbreathe the scrubber because of a panic attack at 50M. No one can say for cvertain that they wont succome to human error. Just my 2C.

Correct me if I'm wrong. I am interpreting "I once managed to overbreathe the scrubber" as falling into the category of "worked too hard".

It is not a case of breakthrough or channeling, correct?

Obviously nobody can say they will never make a mistake. The question is, do the potential pitfalls of a BOV outweigh their potential benefit? I have decided that, for me, they do.

 

[cathal]

Correct me if I'm wrong. I am interpreting "I once managed to overbreathe the scrubber" as falling into the category of "worked too hard".

It is not a case of breakthrough or channeling, correct?

Obviously nobody can say they will never make a mistake. The question is, do the potential pitfalls of a BOV outweigh their potential benefit? I have decided that, for me, they do.

No breakthrough or channeling, was just a panic attack that caused my breathing to accelerate, which over came the scrubber. Like others, in my mind, there was no physical way I was able to remove the loop and replace it with a second stage even though it was right in front of my face. I thought I would drown. About approximately 2-3 minutes inot it, somehow I managed to get my breathing under control. The RMS actual;ly was a help as it was showing me that the scrubber was perfectly fine throughout this episode. Re: pitfalls and benifits of a BOV, someone online once said that "if I am wrong about BOV's I have wasted €1,000 of my money. If you are wrong it might just cost you your life". On that basis, why gamble, err on the side of caution.

 

[LFMarm]

In my rEvo MOD1 training, my instructor had me take the DSV out and stick it just under my chin (gag strap still in place) and insert my BO reg. Once breathing on BO, then there is time to "clean up". I never had any trouble or felt slowed down by that process. The rEvo head strap is plenty stretchy to accomplish that, even on my (very) XL head.

I changed to the rEvo BOV later (and also a bungee necklace for my bottom mix BO) and used that for 2 or 3 years. Earlier this year, I went back to just a DSV (but still with BO bungee necklace). I had a few different problems with the BOV. I decided it was too much trouble and, particularly on a rEvo, just not needed.

Shouldn’t it be easy if you first put on the gag strap and then the necklace for the BO regulator? In case of BO, drop the BOV and get on the regulator that sits on top of it. I still need to try it out but this is how I would do it.

 

[stuartv]

No breakthrough or channeling, was just a panic attack that caused my breathing to accelerate, which over came the scrubber. Like others, in my mind, there was no physical way I was able to remove the loop and replace it with a second stage even though it was right in front of my face. I thought I would drown. About approximately 2-3 minutes inot it, somehow I managed to get my breathing under control. The RMS actual;ly was a help as it was showing me that the scrubber was perfectly fine throughout this episode. Re: pitfalls and benifits of a BOV, someone online once said that "if I am wrong about BOV's I have wasted €1,000 of my money. If you are wrong it might just cost you your life". On that basis, why gamble, err on the side of caution.

Of course it is super easy to armchair quarterback other people's stories, and I wasn't there when you had your issue. The way you describe it sounds like a textbook case of hypercapnia. The part about not being able to remove the loop to switch to a BO reg, I mean.

With no breakthrough or channeling, I don't see how you would go from fine to hypercapnic in an instant.

Let me repeat myself. I wasn't there. So, please don't take this as some kind of accusation. I'm trying to share what I know and ask questions so that I can learn from what happened to you.

The way you describe it makes me have to wonder if you were actually hypercapnic, or if you were simply panicked and breathing really fast from that. Because, if you were not hypercapnic, then the next question is, did you even need to bail off the loop? Getting your breathing under control after 2 - 3 minutes also suggests that it was not a hypercapnic hit.

All of which circles back to, is the benefit of a BOV worth the downsides. You're giving this example to rationalize using a BOV - but in your example you describe having THE symptom that is a reason for a BOV (i.e. that you could not remove the DSV to insert a BO reg), and yet you survived just fine despite not having a BOV. So, would there have been an actual benefit to you in that situation if you had had a BOV?

Shouldn’t it be easy if you first put on the gag strap and then the necklace for the BO regulator? In case of BO, drop the BOV and get on the regulator that sits on top of it. I still need to try it out but this is how I would do it.

My training was bungee necklace BO first, then loop on top of that.

I don't think it would work so good to have the OC reg and hose on top of the loop.

But, if you try it, let us know how you feel like it works.

 

[211ratsbud]

I'm shocked to see the results of the poll showing near a ⅓ of divers using a gag strap. I run a charter and to my recollection Stuart is the only one I have ever seen wear one on my boat.

Late to the conversation, so I'll keep skimming the thread.

 

[Capt Jim Wyatt]

Descriptive epidemiology of 153 diving injuries with rebreathers among French military divers from 1979 to 2009 - PubMed

Gas toxicities are frequently encountered by French military divers using rebreathers, but the very low incidence of fatalities over 30 years can be explained by the strict application of safety diving procedures.

pubmed.ncbi.nlm.nih.gov

Apparently this article supports the use of a gag strap - I have NOT read it.

 

[stuartv]

Descriptive epidemiology of 153 diving injuries with rebreathers among French military divers from 1979 to 2009 - PubMed

Gas toxicities are frequently encountered by French military divers using rebreathers, but the very low incidence of fatalities over 30 years can be explained by the strict application of safety diving procedures.

pubmed.ncbi.nlm.nih.gov

Apparently this article supports the use of a gag strap - I have NOT read it.

If you follow the trail of links, you can eventually get to a link to a PDF of the actual report, instead of just an abstract. That link is this (in case anybody else wants to read the actual report):

https://academic.oup.com/milmed/article-pdf/176/4/446/20893178/milmed-d-10-00420.pdf

 

[mr_v]

I have to revert my vote again. Went back to gagstrap + stock rEvo DSV.

Diving without the gagstrap was not bad or better. It was a bit more convenient for drills - I do several drills before the start of every dive - but that's where the obvious gagless benefits ended. If you use a stock rEvo DSV, good luck finding an aftermarket mouthpiece that fits easily. I tried Seacure and JJ pieces - they were ok but required streching. Using a stock rEvo mouthpiece w/o a gagstrap did not work for me. The mouthpiece is too small to bite comfortably, as it is not long and you can't use your back teeth for extra grip. Of course, I could have gotten a new DSV, but that means more $ spent on things I don't really need.

Also, with the gag strap I felt a bit more security from other divers and people in water. Ginnie folk walked all over me the other day and I was happy to have the strap.

 

[mr_v]

No breakthrough or channeling, was just a panic attack that caused my breathing to accelerate, which over came the scrubber. Like others, in my mind, there was no physical way I was able to remove the loop and replace it with a second stage even though it was right in front of my face. I thought I would drown. About approximately 2-3 minutes inot it, somehow I managed to get my breathing under control. The RMS actual;ly was a help as it was showing me that the scrubber was perfectly fine throughout this episode. Re: pitfalls and benifits of a BOV, someone online once said that "if I am wrong about BOV's I have wasted €1,000 of my money. If you are wrong it might just cost you your life". On that basis, why gamble, err on the side of caution.

I was not there, but it is likely you've outbreathed your lungs.

 

[Andrius Be]

I find it that using gag strap on my rEvo actually benefets me , not for the safety reasons , but planely because of the jaw fatigue. I dive with BOV no need for BO neclace , but after an hour or so into dive I find it nice to be able to relax the jaw muscles and stop biting in to the mouthpeace. Gag strap holds everything nicely in place. Sort of like going on autopilot