dry suit buoyancy

[Thalassamania]

I am not sure what you mean by "oral inflator"
I have a Si-tech exhaust valve, and an Apeks inflator (on suit) which is hooked via an LP hose to an argon bottle (or back gas)

Sorry ... oral inflator on the BC.

On descent, I usually add to the suit first to relieve squeeze but regulate descent with BC.

Exhaust valve is left 100% open all the time.

On ascent, the gas starts to expand in the suit. Since I'm horizontal ascending, I have to lean a bit so my left side is up (to let the gas migrate) and squeeze my left arm (like I am lifting a weight I guess) to exhaust the gas.

if I try to just let the gas escape on its own, it exhausts way too slowly and I feel like the michelin man. I hate any significant amount of gas in the suit on ascent.

i dont seem to have an oral inflator for my suit (but I dont think that affects things much -- it's the venting that is irritating)

My suit(s) vent just fine, I never have that problem ... perhaps the malfunction is the result of your undergarments?

 

[limeyx]

Sorry ... oral inflator on the BC.

My suit(s) vent just fine, I never have that problem ... perhaps the malfunction is the result of your undergarments?

Got you on the inflator.

It's not (I think) a malfunction on my suit, more a result of a horizontal ascent.
I am guessing if I chose to ascend in a more vertical manner, the valve would be by default higher up compared to my body and may vent more automatically.

I have used 300G fleece, DUI 200G thinsulate (with and without an extra thinsulate vest), DUI 400G thinsulate and DivingConcepts 200G thinsulate

with similar results so I'm loathe to blame "bad gear"

 

[Tigerman]

Not really. Think of it this way.
Imagine I could fill my drysuit with some magical substance like air that removed the squeeze and kept me warm, but had no buoyancy increase whatsoever.
To me, this would be a preferable solution, resulting in a much easier ascent (of course this magic substance does not expand on ascending either



I would then be using only the BC -- the fact that the air in the suit currently adds to the buoyancy is just a side-effect that "air does that" nothing to do with air in the drysuit making you "neutral" or not -- you need to put air or argon in to remove the squeeze, and the fact that it give you a bit of lift is just a side-effect.

Youre talking about a wetsuit... Which kinda has the problem it wont keep us as hot, especially in the water where we dive dry.
Also, if what was in the suit didnt compress, like air does, there would be no squeeze so no need for inflation to begin with..
As far as not expanding on ascent, thats what the dump valve on my arm is for. Adjust it porperly and it wont be an issue, it leaks out by itself..

 

[Thalassamania]

Got you on the inflator.

It's not (I think) a malfunction on my suit, more a result of a horizontal ascent.
I am guessing if I chose to ascend in a more vertical manner, the valve would be by default higher up compared to my body and may vent more automatically.

I have used 300G fleece, DUI 200G thinsulate (with and without an extra thinsulate vest), DUI 400G thinsulate and DivingConcepts 200G thinsulate

with similar results so I'm loathe to blame "bad gear"

I use an older set of Viking underwear that is fleece in and slick nylon out, sometime adding other things under it, but yes, with a valve in the conventional shoulder position, it does help to get at least a tiny bit head up.

 

[rakjar]

I use my BC and just add air to take the squeeze off.

 

[b1gcountry]

My suit(s) vent just fine, I never have that problem ... perhaps the malfunction is the result of your undergarments?

That's not a malfunction, its gravity. The air is going to go to the highest part of the suit. If you want it to vent, you need to have the air go to the exhaust valve.
Tom

 

[Thalassamania]

... If you want it to vent, you need to have the air go to the exhaust valve.
Tom

As I said:

... but yes, with a valve in the conventional shoulder position, it does help to get at least a tiny bit head up.

 

[overandunderwater]

As a person that completed his DrySuit last month with two different instrructors I can tell you one instructed use the BCD one instructed DS, both said however do what is right for you. PADI has a guideline, on buoyancy but that's it. I was having a simliar issue at first with my rented suit as it was long in the legs, air was trapping there. I switched to a better fitting suit and added a weight belt. I tried both and like the DS buoyancy as it's one less hose to worry about but that's not the point. The point is use what makes you comfortable and talk to your instructor one on one. I'm at 15 DS dives now and am at that feeling comfortable point so just stick with it. Trust your body, you'll start keeping your legs down a little more so air doesn't collect. At least you have steel which is a lot easier to deal with low air. Just got back from Monterey where most of the divers where wet. While they were sticking warm water hoses down there suits I was munching on a sandwich, cold drink and shirt off as I was toasty. It's all worth it.

Randy