BOV/gag strap vs. OC second stage on bungee necklace

[rjack321]

Where's a good place to buy a gag strap? I don't want to get hosed.

Both AP and Drager make them. Both imported to the US so they end up being expensive

 

[toby43]

Hi,

Newbie JJ diver here. I'm starting a new thread about a topic that came up tangentially elsewhere. Maybe better to start on Rebreather World? Wasn't sure if there were more CCR divers here or there...

My instructor (and the JJ distributor) both feel that an OC regulator on a bungee necklace, plugged into an off board gas source (side mounted AL 80) is the best bailout configuration. I also know that JJ used to have a BOV, but they don't offer one now under the current CE. I'm actually comfortable with this configuration, having bailed out several times with this setup in training. I also really instinctively like the idea of a completely redundant system, separate from the rebreather.

However, I have seen a lot of talk about the benefits of a BOV used with a gag strap in cases where a quick switch to OC is necessary (specifically, suspected hypercapnia). One article sent to me was particularly interesting (see attached). Basically, this was a review of rebreather accidents in French military divers, with 54 cases of loss of consciousness but only 3 deaths. Since a loss of consciousness at depth is normally rarely survivable, a 94% survival rate is very impressive. The raw data isn't available, but they do note that a retaining strap for the loop was standard practice.

I wouldn't want to use a strap without a BOV since that it would make it more difficult to quickly get off the loop, so I was thinking about adding an aftermarket BOV to my JJ (i.e. Golem Gear Shrimp). I was also thinking of putting an OC regulator on my bailout tank in addition to the hose to the BOV, stowed like on a deco tank with a bungee, to provide redundancy in case of something like a damaged loop or lost mouthpiece.

What do you experienced CCR divers think about this question?

Thanks in advance!

Only reason JJ gave up with BOV was because they couldnt get 100m CE with one. Dont believe me? Ask Dave Armstrong.

 

[TotDoc]

If the reg is stuffed on the bottle and sidemounted you can lose a significant amount of gas if it happens to get knocked while the mouthpiece is facing up. Same reason why deco bottles are stored pressurized but off.

This is not entirely true - deco bottles are stored off because you are not going to have a reason to switch to them unexpectedly, and because they are often dropped somewhere unattended, where gas loss could go unrecognized. Bailout is always on your person, though, so there shouldn't be any unrecognized gas loss.

Bail out should be left on, because - well, it is needed for bail out. Gas loss is always possible from bumping the reg, but I question that you will lose a significant amount. It would be a different story if I had an extra second stage on my 3L dil bottle, but from a 40 or 80 or larger - you'd have to really ignore it for a while to drain that bottle significantly by a bump.

If that scenario were really a concern, wouldn't we need to practice switching off tanks during gas switches on sidemount to keep from draining the tank we aren't currently using? I figure we probably don't do that because of the same reasons - we potentially need the other reg available immediately, and realistic gas loss from a reg on your person and easily accessed is likely to be minimal.

The rebreather is quiet enough that any bubbling - even minimal stuff that would go unnoticed on open circuit - is pretty easily detected and addressed without catastrophic gas loss.

 

[TotDoc]

Where's a good place to buy a gag strap? I don't want to get hosed.

rEvo safety mouthpiece (bite-piece with straps)

I haven't found any place in the US that seems to have any kind of deal on these. Since they apparently come on revo units, maybe you can find someone who has a revo that doesn't like it and wants to switch to a regular mouth piece?

But at least it comes from a place where you would get it quickly.

I have been debating picking one of these up too, but I figure I will talk pros and cons about this with my rebreather instructor before I go making any more changes to my unit.. It does seem like a smart addition, though, when used with a BOV.

 

[TotDoc]

I think a bov is indispensable.

It allows you to get on oc quickly without having to hold your breath and it provides a method for your buddy to put you on oc if need be.

This is the reasoning that got me to pick up a shrimp - but the second part about a buddy being able to put you on OC is why I am considering a gag strap. I figure if something happened and I went unconscious, I'd need something to keep the reg in my mouth so that my buddy COULD switch me to OC. I just don't know enough about it to know if there are any practical downsides to running the unit this way. With my limited knowledge on the issue, it seems like a no brainer - but if that were the case, I'd think I'd see a lot more people running them.

 

[rjack321]

This is not entirely true - deco bottles are stored off because you are not going to have a reason to switch to them unexpectedly, and because they are often dropped somewhere unattended, where gas loss could go unrecognized. Bailout is always on your person, though, so there shouldn't be any unrecognized gas loss.

Bail out should be left on, because - well, it is needed for bail out. Gas loss is always possible from bumping the reg, but I question that you will lose a significant amount. It would be a different story if I had an extra second stage on my 3L dil bottle, but from a 40 or 80 or larger - you'd have to really ignore it for a while to drain that bottle significantly by a bump.

If that scenario were really a concern, wouldn't we need to practice switching off tanks during gas switches on sidemount to keep from draining the tank we aren't currently using? I figure we probably don't do that because of the same reasons - we potentially need the other reg available immediately, and realistic gas loss from a reg on your person and easily accessed is likely to be minimal.

The rebreather is quiet enough that any bubbling - even minimal stuff that would go unnoticed on open circuit - is pretty easily detected and addressed without catastrophic gas loss.

You obviously don't scooter on your rebreather.

You can also get the drager gag straps in the USA here:
safety mouthpiece (bite-piece with straps) R521 *Buy rEvo Rebreathers at OceanEdge Outfitters 908-359-5468

There's no "deal" because they are all imported from the same place in Germany.

The AP version is much cheaper but not readily available
Rebreather Headstrap | AP Diving

 

[TotDoc]

You obviously don't scooter on your rebreather.

Sadly, you are correct on this one. So please educate me a bit here - do you really have no ability to notice a freeflowing reg while on a scooter? If you had a reg on a bungee under your neck like you would with the short hose on doubles or sidemount, or if you had a long hose clipped off on your right d ring, does using a scooter mandate that you have a shutoff on those regs, too?

 

[PfcAJ]

You obviously don't scooter on your rebreather.

I scooter a lot and with a bunch of regs turned on. Backup, long hose, bov, drive reg are all on at any given time.

It's super obvious if a reg cuts loose and even then it's not something that happens all that often.

 

[rjack321]

I scooter a lot and with a bunch of regs turned on. Backup, long hose, bov, drive reg are all on at any given time.

It's super obvious if a reg cuts loose and even then it's not something that happens all that often.

Yes but its not stuffed riding in your armpit. There's a big difference with a reg purging under your neck or on your right chest and a reg stored on the tank, which is riding in your armpit, burping gas behind you. And if you are in a mixed team you can lose a significant amount of gas back there that doesn't sound all that different than your buddies exhalations.

 

[PfcAJ]

Yes but its not stuffed riding in your armpit. There's a big difference with a reg purging under your neck or on your right chest and a reg stored on the tank, which is riding in your armpit, burping gas behind you. And if you are in a mixed team you can lose a significant amount of gas back there that doesn't sound all that different than your buddies exhalations.

The reg position on a stage bottle vs a sidemount bottle is like 6 inches.