New CCR Diver with gagging issue

[junky pesco]

Hey y'all,

I've been reading these forums for quite a bit for some info which could possibly address an issue I'm having but found nothing so far. I'm a new CCR BM diver and just completed MOD 1. Diving so far has been great (10 hours), working on my trim and ascents (balancing the counterlungs, wing and drysuit).

The issue I'm having is at around 3m (10ft) and above as I ascent to the surface, I start to gag. I've realised that I need to be clearing more air from the loop as I ascent (I normally vent through the nose) due to the expanision, however could the positive pressure being created be the cause of the gagging?

Clearly I need to spend more time getting used to it all, but some advice would be great if anyone expereinced this issue in the past.

Thanks!

 

[kissonerga.ccr]

It’s sort of natural – gas in the loop is expanding the greatest this close to the surface, relative to deeper parts of ascent. So, venting the excess volume is how you deal with it. But then, it creates a great opportunity to practice a really slow ascent – if you can hang at 2m, then 1.5m, etc., expansion will also stop for that moment. So, perfect your super-slow ascents. If you have any gas left in your bcd and dry suit, learn to manage those to fine-tune your ascent rate. I would typically have an empty bcd from 6m and up, and adjust buoyancy just by the position of my elbow, dump valve fully open. In some sense, having a long(-ish) deco stop at 6m helps – plenty of time to dial in the exact combination of drysuit, bcd and loop volumes.

With eCCr, prior to the ascent from the last stop, I bump PPO2 to 1.0-1.2 (unless I’m coming off a deco with 1.4-1.5 already) – this way, solenoid is not firing on the way up (which it will be if it’s set to the low set point – or high, even worse!), further adding gas to the loop

 

[junky pesco]

Thanks for the advice, indeed one of the first steps is to lower my PO2 so the solenoid stops firing (once out of any deco obligations). Will work on ascending 1 metre every minute towards the last 3m or so to get used to managing the gas expansion.

 

[Dsix36]

Early in my RB diving, I had a similar issue. When ascending and venting out my nose it would cause a slight gag reflex. I found that if I vented around my moth it did not happen. Turns out I was just venting to much volume at once rather than smaller amounts more frequently. I found that slowing my final ascent to allow more smaller and more frequent vents from my nose solved the issue. After a bit more time on the RB the issue just vanished regardless of volume.

 

[Merida Cave Diver]

This is interesting. I’m not sure why but I never think of venting out my nose for some reason. I always seem to vent out my top lip.

 

[Capt Jim Wyatt]

The problem with venting through your mouth is the greater possibility of getting water in the loop versus venting through your nose.

 

[Merida Cave Diver]

The problem with venting through your mouth is the greater possibility of getting water in the loop versus venting through your nose.

Yeah that’s a great point, it’s something I need to put into conscious thought.

 

[Capt Jim Wyatt]

Yeah that’s a great point, it’s something I need to put into conscious thought.

Yea I recall trying to get into the habit of nose exhaling. For so long I ( and likely you) have always exhaled through my mouth on scuba. It does take a conscious effort to change.

 

[umicore]

Hi guys. Is there any reason for venting from lips rather than via nose? For me it is more natural to do it via nose. As mentioned here, when I do it via lip and the loop presure is not high enough, I get wanter in the lool. Thank you

 

[L13]

Hi guys. Is there any reason for venting from lips rather than via nose? For me it is more natural to do it via nose. As mentioned here, when I do it via lip and the loop presure is not high enough, I get wanter in the lool. Thank you

Nose venting can cause fogging or water leaking into the mask for some people. For others, these are non-problems.