Mouthpiece Retaining Head-strap

[GKAM]

Reading the current thread, I still have not found a single argument why the use of a retainer strap is needed while RB diving with a BOV installed.

All BOVs are connected to ample supplies of OC gas breathable at any depth range. Right? One would think a strap + BOV introduce unnecessarily complicated configuration to mitigate a non existing problem.

/GKAM

 

[Bythesea]

Reading the current thread, I still have not found a single argument why the use of a retainer strap is needed while RB diving with a BOV installed.

Did you miss the bit about being unconscious and drowning {apparently the most common cause of RB death} due to the mouthpiece falling out. Having a BOV wont prevent that.... or am I missing something?

 

[GKAM]

Did you miss the bit about being unconscious and drowning {apparently the most common cause of RB death} due to the mouthpiece falling out. Having a BOV wont prevent that.... or am I missing something?

Please help me understand your concern here. Are you afraid that the moutpiece may fall out and you will drown during some random RB dive or is it the case of passing out and then dropping the mouthpiece.

If it is the latter, shouldn't your concern be how to prevent passing out in the first place rather than relying on a gag strap to marginally improve chances of survival in such situation?

/GKAM

 

[Bythesea]

Please help me understand your concern here. Are you afraid that the moutpiece may fall out and you will drown during some random RB dive or is it the case of passing out and then dropping the mouthpiece.

If it is the latter, shouldn't your concern be how to prevent passing out in the first place rather than relying on a gag strap to marginally improve chances of survival in such situation?

/GKAM

Either way, I can't breath water, the likelihood of making a comeback is slim, breathing bad gas may not have such dire effect and may survive.

Anyway, £15 insurance against the slim chance of banging my head. I will happily spend that £15, give it a go and then make a decision.

The majority of RB deaths have been shown as drownings.... the chances of drowning if you are breathing anything other than liquid are slim...

Reliance? Why jump to the assumption that because of a £15 bit of dive tat I will disregard all forms of prevention?

A bit of real world thinking on all the above seems to conclude in ..... might aswell give it a go, it is no biggy....

 

[Peter L]

Please help me understand your concern here. Are you afraid that the moutpiece may fall out and you will drown during some random RB dive or is it the case of passing out and then dropping the mouthpiece.

If it is the latter, shouldn't your concern be how to prevent passing out in the first place rather than relying on a gag strap to marginally improve chances of survival in such situation?

/GKAM

1. See Post 1 ..... $%^ happens....

2. Unconsciousness or incapacitation for any reason including heart attack for those unfit over 40 divers out there needs that the mouth piece stays in place for a successful rescue.

3. More than a few people have had the mouthpiece come away from the DSV/BOV, not fun for doing deco and at minimum a flooded loop.

I wear an AP Valves gag strap for point 2 & 3 more than the risk of point 1, the reality is that it also takes the strain off my jaw and the bite piece which helps me enjoy deco rather than hating it.

On another forum the topic of recovering a CCR diver resulted in the general conclusion that no OC diver would even bother IF they found you loop out and more so they would not know what to do. Breathing water is fatal in seconds, breathing low PPO2 in minutes, I would rather go with the minutes option..

P

 

[GKAM]

Either way, I can't breath water, the likelihood of making a comeback is slim, breathing bad gas may not have such dire effect and may survive.

Anyway, £15 insurance against the slim chance of banging my head. I will happily spend that £15, give it a go and then make a decision.

The majority of RB deaths have been shown as drownings.... the chances of drowning if you are breathing anything other than liquid are slim...

Reliance? Why jump to the assumption that because of a £15 bit of dive tat I will disregard all forms of prevention?

A bit of real world thinking on all the above seems to conclude in ..... might aswell give it a go, it is no biggy....

Not a question of cost here - I don't believe this is what we are discussing. Pls note the original use of the strap is to prevent spitting out the mouthpiece in case of convulsions from oxygen exposure. A BOV connected to ample supply of suitable breathing gas actually deals with this problem in a much more effective way. Most military units do not offer the luxury of going to OC.

A hypercapnic situation is also best dealt with by switching the BOV to OC. The case of hypoxia is more tricky as one gradually lapses into such state and may be too impared to react. Does staying on a hypoxic loop improve your chances of survival? I seriously doubt that, esp once you start to ascent. If there is one good thing you can do, is to go on richer gas.

In my book the best approach is to *prevent* any of the above situations form ever actually hitting you. A gag strap introduces more problems than it solves...

Anyway - this is just an internet debate and its worth is as much as you paid for it

/GKAM

 

[GKAM]

1. See Post 1 ..... $%^ happens....

Yup, it happens. Not sure if OC or CCR is any better or if a strap would help. What could have probably made a difference is the presence of a buddy. If you bang your head so hard you pass out, chances of recovery on a solo dive are pretty thin no matter what.

2. Unconsciousness or incapacitation for any reason including heart attack for those unfit over 40 divers out there needs that the mouth piece stays in place for a successful rescue.

Hey, should people unfit for diving be underwater in the first place? Just sayin'...

3. More than a few people have had the mouthpiece come away from the DSV/BOV, not fun for doing deco and at minimum a flooded loop.

Well, if the mouthpiece gets knocked off you should be able to put the loop back in your mouth without much trouble... If it comes off because it was not secured properly or was torn, then it was your fault for not inspecting your gear prior to entering the water. If too worried about this, just carry a spare + zip tie. You can always fix this underwater.

Again, I am just presenting the case for a different approach. It seems like everyone on this thread has already made up their minds to purchase though... :big:

/GKAM

 

[Bythesea]

Again, I have more chance of surviving tox than breathing water.

You don't like them, fine, not an issue.. I will give it a go and make a decision...

If I don't like it then that is what Ebay is for....

 

[w ripley]

You obviously don't want to use one? Fine, then don't. I don't think anyone really cares one way or the other about your personal choice(s).

Diving is all about setting up your rig so you are comfortable in the water.

I personally chose to use one because I know that if I go unconscious, for any reason, my mouthpiece (OC or CC) is most likely going to drop out of my mouth. Seen a friend die this way with an oxtox hit. But, if I am lucky enough to regain consciousness, at least the odds will be in my favor of not drowning (i.e., surviving) if my mouthpiece is already where it should be when I take that critical 1st breath. Can I absolutely guarantee that it will be there when I need it? Of course not, even with the testing I constantly do.

Using one is just a personal decision. I don't find that many divers employ a method of retaining their mouthpieces, and they know everything that's been posted in this thread. So it's obviously not a big issue to most. You can say the same thing for lots of aspects of diving.

I dive a large canister with 2 steel 45s/7L dil tanks mounted to it, each with their own manual adds, 2nd stages and an isolater manifold between them. I also carry SM BOs + plant stages & O2 bottles when caving. I could care less whether or not anyone agrees with my setup: It's what makes me feel comfortable on a 4-7 hour solo cave dive.

If we all felt there was only one way to dive and only one rig and setup we wouldn't have these forums.

 

[steve6690]

Please help me understand your concern here. Are you afraid that the moutpiece may fall out and you will drown during some random RB dive or is it the case of passing out and then dropping the mouthpiece.

If it is the latter, shouldn't your concern be how to prevent passing out in the first place rather than relying on a gag strap to marginally improve chances of survival in such situation?

/GKAM

You should be doing both IMHO. A simple example : I drive carefully, in an attempt to minimise the risk of a collision. I keep my car maintained in a safe condition so that it won't go out of control and try to kill me. I still wear a seat belt though..

 

[PeterN]

Don't discard comfort as a safety factor. Also less fatigue is a no small thing.

After all the ifs about putting up with the donning and doffing issues and if the thing happens to fit your gob, if you get past that, it makes diving easier. On longer dives particularly.

It is worth trying....

Peter

 

[GKAM]

You obviously don't want to use one? Fine, then don't. I don't think anyone really cares one way or the other about your personal choice(s).

Now that's not very nice Mr Ripley. One could say the same for you

So far this thread has been about bringing arguments for and against the use of a head strap. The aim is for different sides to present their views and allow the participants to draw their own conclusions and decisions. Else, what's the point of a (good) forum in the first place?

/GKAM

 

[Bythesea]

You should be doing both IMHO. A simple example : I drive carefully, in an attempt to minimise the risk of a collision. I keep my car maintained in a safe condition so that it won't go out of control and try to kill me. I still wear a seat belt though..

This is my thinking....

 

[philsiswick]

I use a gag strap on my JJ and my Inspo with no problems.

Which one do you use on the JJ? I made one for the Inspo, but wasn't very pleased with it.

I'm most convinced by the rEvo one. Am going to fit something this year.

 

[nickb]

Pls note the original use of the strap is to prevent spitting out the mouthpiece in case of convulsions from oxygen exposure. A BOV connected to ample supply of suitable breathing gas actually deals with this problem in a much more effective way.

What way would that be?

I had a tox in 2010. I was fortunate enough to be shallow and realise what was happening so I got the hell out of there and got the attention of the surface cover. Trust me, my BOV would not have made the slightest difference to the outcome. If I had convulsed in the water, even on the surface, I may have drowned before anybody got to me.

 

[gianaameri]

A BOV with a Crown Strap suitably designed to retain the mouthpiece in the mouth, and reduce water ingress, is a means to ensure the risk of the man-machine system has been reduced to as low as reasonably practicable.

Far more important is to design the man-machine system to prevent entirely the 3H, but until this is possible, BOV and Crown Strap are essential, or the rebreather is not ALARP compliant.

Any cheap device won't necessarily cut it... so far the only one I have found to actually do the job described above, rather than merely support the DSV/BOV, is the Draeger model.

There has been one incident where the buddy said that if he only had an extra moment he could have prevented the drowning due to unconsciousness of a CCR diver.

When the accident analysis on the fatality of Jordi Mateo will be released by his students who brought his body to the surface, it will be interesting to see the extent a Draeger Crown Strap could have made that little difference between life and death.

Jordi had a Meg with Golem Shrimp, but no Crown Strap (my understanding to date).

 

[Dave1w]

I ordered a strap from AP Valves and it arrived quickly enough for me to give it a go this weekend over a few dives. It was easy enough to fit and my thoughts were to use it with an Aqualung lip shield thing similar to the rEvo setup.

I had mixed results. The strap itself was actually better than I imagined for the price with a solid crown piece and two straps that each had a large o-ring on the end which went around your breathing hose.

I am using a Golem Shrimp on my Classic Kiss, and when it was all attached up it was nice and secure, but due ( I think) to the shape of the Shrimp, and the angle up to the crown, it seemed to push the shrimp into my mask, which resulted in pretty bad mask flooding. I tried with and without the lip shield, and had some success by dropping the strap down to the back of my head. I am sold on the idea, but will need to do a bit of fiddling I think to get it working properly for me.

The strap on the ALBOV on my APOC does the job well and pulls from below the centreline I think, so no interference with the mask.

I actually have Drager Ray hoses on my Kiss, and they are that bit tighter, allowing me to not bite down while still holding a good seal, with the lip shield it was even better, but the mouthpiece is a little short to have that on comfortably, so Maybe I'll try a different mouthpiece.

I will try and get it sorted, as I do think the strap is a good safety item.


Sent from my iPad using Tapatalk HD

 

[Ivan Calcoen]

Haven't used a crown strap on my Dolphin.
The Apoc came with the strap.
In the beginning it felt annoying.
Now I am getting used to it and must admit I start to like it.
I did have to find the proper 'tension' but by now I wouldn't dive w/o it.
I did remove the OC trigger cord (the one that triggers the BOV when you take out the mouthpiece out of yr mouth), it was just 1 strap too much.
As mentioned above, also no fatigue in the jaws which I did have before.
So, for me all in all +1 for a crown strap.

Ivan

 

[Garspeed]

I run an Inspo with an AP gag strap and have done for some time. Because of this thread I tried a little experiment on my dive on Sat. I swam around for about 10 mins with no pressure on my lips or teeth to maintain the mouth piece in place. I truly expected to find that I took on some water but I can confirm to my surprise that I did not. Not necessarily the most conclusive experiment in the world but I am a believer in gag straps and this still amazed me.

Go add on to your unit - you know it makes good sense!
Gar

 

[Paul Haynes]

Reading the current thread, I still have not found a single argument why the use of a retainer strap is needed while RB diving with a BOV installed.

All BOVs are connected to ample supplies of OC gas breathable at any depth range. Right? One would think a strap + BOV introduce unnecessarily complicated configuration to mitigate a non existing problem.

/GKAM

Apologies for late reply, just catching up here.

In response I offer up what is consistently emerging as statistical fact - drowning is the single most common cause of rebreather deaths, which I would argue is a long way from being a "non existing problem".

Having almost immediate access to alternative breathing gas via a BOV does go towards mitigating the hazards of hypoxia, hyperoxia and hypercapnia, however the use of a BOV still requires a conscious action, something not possible whilst unconscious. For what ever reason, Loss of Consciousness (LoC) may occur with little or no warning. Yes we strive to avoid any trigger that might result in disabling injury leading to LoC, however, a reality we can choose to confront or ignore is that despite our best efforts to avoid incident triggers, LoC is a very real possibility when using a rebreather. A mouthpiece retaining strap therefore provides a final layer of defence in our efforts to mitigate the inevitable consequence of LoC whilst underwater. As I've stated previously, there are no guarantees, it is about managing risk by reducing the likelihood of encountering the single largest cause of rebreather deaths. A consistent theme to eye witness rebreather fatality statements is "I turned around and noticed the mouthpiece was not in place". By protecting the airway and loop from flooding, there is greater potential of surviving LoC by self preservation if consciousness is regained or by buddy rescue.

I hope this provides a stronger case for the use of a retaining strap, BOV or not.

Rgds Paul