Has anyone had a “free flowing” nose on a rebreather?
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broncobowsher
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It can happen holding a steady depth.
I want to say that different masks make it more/less sensitive. But was never a cure.
I've had it happen after several hours on OC, I don't remember it happening on CCR though. I always assumed it was soft palate fatigue, since once it starts, it doesn't really stop for me. Actually I can take my mask off for a bit, and it goes away once I put it back on. A little rest goes a long way it seems.
The more I research this, the more I believe you are correct -- it seems to be a soft palatal air leak (also called Stress Velopharyngeal Insufficiency). This seems to be an issue with some musicians who play wind instruments. I didn't think to take my mask off when it started...I may try that next time it happens.
An interesting article on it I found if anyone is interested.
First time: Happened to me on a KISS SideWinder after an extended period of semi closed breathing during initial crossover training with Edd. Upon ascent I could not stop exhaling through my nose and had to hold my mask on to keep loop volume. I ended up bailing out and sitting still for a while before getting back on the loop.
Second time: Happened while ascending also and it was helped by maintaining horizontal trim position. This was on the SW again.
Never happened on any other unit. I have about 500 hours total on CCRs. All back mount CLs.
The snorting happens sometimes at or close to Min Loop Vol. I try and keep the loop slightly above MLV and don't usually have a problem even on longer two to three hour trimix dives.
Second time: Happened while ascending also and it was helped by maintaining horizontal trim position. This was on the SW again.
Never happened on any other unit. I have about 500 hours total on CCRs. All back mount CLs.
The snorting happens sometimes at or close to Min Loop Vol. I try and keep the loop slightly above MLV and don't usually have a problem even on longer two to three hour trimix dives.
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Alaskan Scuba Dude
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The last time I used a rebreather, my nose was blocked and I had a bad case of the flu. Try venting gas through your lips instead.
Easier said than done. Depends upon the mouthpiece and if there’s a gag strap. Runs a risk of letting water in the loop and easiest to do if not horizontal, so there’s some gas pressure.
I experienced this, too. Felt a bit like snorting, like already mentioned. Using a JJ with DSV, gas is usually Trimix with a quite high He fraction. E.g. 15/55 for a 30m dive.
It often happend when I had to "work" a bit heavier (taking pictures) or when a bit excited. CO2 can be a contributing factor. Happend quite early in the dive, got better when concentrated on stop "working" and during deco.
Don't want to be rude, but it maybe is related to weight / fitness regime. I tend to snort when sleeping. Reducing my weight improves at least the snorting...
It often happend when I had to "work" a bit heavier (taking pictures) or when a bit excited. CO2 can be a contributing factor. Happend quite early in the dive, got better when concentrated on stop "working" and during deco.
Don't want to be rude, but it maybe is related to weight / fitness regime. I tend to snort when sleeping. Reducing my weight improves at least the snorting...
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