Seeing bubbles coming out from drysuit

[BlueTrin]

Because I can vent the suit by lifting my left elbow and rolling slightly to the right. When I've vented enough, I roll back and lower my elbow. Works like a charm. And as long as I'm in reasonably horizontal trim, I can add more gas to my suit than I'll ever need.

Why would you dive with your dump valve closed?

Where is your valve ?

I wonder if my valve is a bit too high in the shoulder.

 

[BlueTrin]

Wait, why can't you add gas if your valve is open? I dive like this all the time. If you're seeing inflation gas escaping as soon as you add it, to me it sounds like your too head up or the suit is far too full already.

I think it’s one of these but I suspect I vent air without knowing sometimes and I am looking to have visual feedback

 

[Storker]

Where is your valve ?

Someplace on my left upper arm. Pretty standard placement. Haven't noticed much difference between the three suits I've had (one Scubapro neo, one Waterproof trilam and one Ursuit trilam).

 

[BlueTrin]

Someplace on my left upper arm. Pretty standard placement. Haven't noticed much difference between the three suits I've had (one Scubapro neo, one Waterproof trilam and one Ursuit trilam).

Ill get someone to video me.

That will tell me if I am heads up then I can work from there.

 

[Storker]

I used the wrong word: I didn’t mean leak but vent.

There's a noticeable difference between those.

I suspect my trim is sometimes heads up or maybe I have put too much air and vent air.

Might well be. When I go heads-up for a shot, I start venting. It's a slight PITA, but I prefer the easier venting I get by diving with the valve close to full open. You might try closing the valve, but then you'll have to press it every time you want to vent. That's what they taught at the OW class I took.

It’s not easy for me to tell if I vent air as I cannot see the bubbles coming from my shoulder.

You should notice. If you stay neutral, you're not venting. If you become steadily more negative, you're venting.

 

[elgoog]

I attached a screencap of where my exhaust valve is. It's also in the "normal" position - as in, I didn't tell DUI to do anything different.


When my suit vents, I can't see the bubbles but I can hear them (even with a 10mm hood) and certainly feel the gas escaping. Hearing the bubbles may be due to my venting technique bringing my upper arm close to my head so YMMV.

@BRT mentioned closing the valve to allow you to run more gas in the suit at depth. This is totally possible but make sure you're still able to vent as much as you would need. This is going to be practice and a little trail and error. It's worth a shot if you like running your suit fuller. Few of my local buddies do this as well and I see them adjusting the exhaust valve during the dive - personally, it's one extra thing to do and I can't be bothered to mess with it but, again, YMMV

 

[BRT]

I used the wrong word: I didn’t mean leak but vent.

I suspect my trim is sometimes heads up or maybe I have put too much air and vent air.

It’s not easy for me to tell if I vent air as I cannot see the bubbles coming from my shoulder.

Close your valve a bit.

 

[taimen]

I had a SAC of 24 during my last quarry dive and I think my SAC increases by 6 when I wear a drysuit.

How do you measure your SAC and what is the water temperature compared to air temperature?
If you use an air integrated computer to calculate sac for the whole dive, pressure drop from cooling of your gas in cold water will contribute to your increased SAC (compared to temperate water wetsuit dive).
Do you often add gas to your suit when not descending? That would mean you are venting unnecessarily.

 

[BlueTrin]

How do you measure your SAC and what is the water temperature compared to air temperature?
If you use an air integrated computer to calculate sac for the whole dive, pressure drop from cooling of your gas in cold water will contribute to your increased SAC (compared to temperate water wetsuit dive).
Do you often add gas to your suit when not descending? That would mean you are venting unnecessarily.

I think I lose a bit of buoyancy over time like you said but I am not 100% sure and I thought checking if I vent bubbles without wanting to would be good.

I calculate the sac using pressure used during dive factored by average depth, time and cylinder size.

Water is about 15C now and air temp was 25C. There is a bit of me breathing really hard (unconsciously) until I get used to the water temp unless I force myself to breathe slower.

 

[Storker]

I calculate the sac using pressure used during dive factored by average depth, time and cylinder size.

As long as your tank is 200 or 232 bar, you'll get decently correct numbers by using the ideal gas law. If you use 300 bar tanks, you have to factor in compressibility (or use the van der Waals equation of state, which is only suitable if you're more than averagely nerdy. I am, so I'm using the vdW equation...)

Water is about 15C now and air temp was 25C.

Ah. IOW full summer. I believe we had that last year, can't remember seeing anything like that this year.