Dry suit stuff.

[Gary D.]

Yesterday I was on a rather boring dive just checking the area where our jumper died. Not much to do except miss the sunken debris and swim up the river and back down the river for around 300 yards in some reduced visibility.

I started thinking about all the time we spend talking about dry suits and buoyancy control. I think we are all on the same sheet of music but just getting our thoughts out differently.

No matter what you do with a modern dry suit you are using it for buoyancy control. It’s all in how it is projected.

In the days prior to fancy zippers, inflation and exhaust valves we just let the suit squeeze the living crap out of us. You came up looking like a road map of the US. There were some tricks we pulled to lessen the problems but for the sake of this post lets not bring those up. We didn’t have BC’s back then either.

Today you put on an under garment that somewhat matches the comfort level you desire. Then on goes the suit, you’re zipped up and burp it to get rid of excess air.

Once you enter the water air has to be added to lessen the effects of the squeezing water pressure. That’s a given.

Now here is where I think we get off track in our communications.

The Mfg. and instructors, for the most part, say don’t use the suit for buoyancy control. That’s an impossible task unless you refuse to counter the squeeze the water pressure IS going to cause. The instant you touch the inflation valve, you ARE using the suit for buoyancy control whether you intend to or not.

On yesterday’s dives, as well as hundred’s of others, I had a light squeezing of the suit equally on my body, arms and legs. As I went deeper I added a short blasts of air which lessened the squeeze and leveled me off at that depth. As I ascended the suit burped and again I was leveled off at that depth. The process just happens over and over as the depth changes resulting in a level attitude and comfortable dry suit pressure.

If I allow any more suit squeeze I will start getting water in through some of the seals, mainly the neck.

My weight adjustment is such that I can do this over and over without ever touching my BC. If I put any air in the BC I’m like a cork and would have to add more weight defeating proper weighting ideas.

I can get my weight so precise that way that just a slight inhale or exhale will cause me to rise or drop gently.

When I exit the water I need to break a seal to get air into the suit to relieve the vacuum like suction between the suit and my body.

On the surface I use the BC for buoyancy and that’s about it.

So is this a better explanation of using the suit for buoyancy control?

Gary D.

 

[NOVIZWHIZ]

Actually I don't use my dry suit for bouyancy/ flotation at all...don't even hook up the supply to the inflator. I find that the squeeze around my neck is too uncomfortable with any air in the suit, or if I turn my head wrong it burps itself through the neck seal..... or if I get head-down the air will go to my feet and make my legs float. I dive a neoprene Harvey's Shell Hog...couple of toots in my vests once I hit bottom gives me a little bouyancy, couple of more and I can ascend, full inflate on top.
PS - I HATE dry suit diving!

 

[Boogie711]

I think you and I must have very different tolerances of what is an "acceptable" squeeze, Gary.

I prefer to have the least amount of air in my suit as possible. On an 80 foot dive, I'll maybe give myself 2 puffs of air. The lower the amount of air in my suit, the EASIER it is to control trim and bouyancy. I don't get a "floaty feet" sensation that other people tend to talk about. In fact, I find it quite comfortable, because I can move around underwater in just about any position without trying to "ride the bubble."

I've never had a neck seal leak due to 'excessive squeeze' - perhaps you trimmed them too loose?

 

[NOVIZWHIZ]

...or like me - he's got a skinny neck and wrists...

 

[JDostal]

I dive the same way as Gary. I don't use my BC, because using it would be a little excessive.

As I descend and I start noticing my suit getting tight, I let in some air to relieve the pressure. Just enough to relieve the squeeze and let the insulation loft up a little bit.

Then I'm neutral - no air in the BC at all. It's not like I'm *trying* to use my drysuit as a buoyancy device....it just works out well that way. On top of that, too much squeeze is bad for me - when I'm in 39 degree water (common in many of my diving spots...) you get too much squeeze and the insulation quits working and you get cold FAST! I like a little bit of air in my suit to keep me warm.

When I dive with my doubles, then I start using my BC, because I'm heavy and need more lift than the "squeeze relieving" air in my suit can provide.

 

[Boogie711]

What kind of drysuit underwear are you guys using that needs loft in order to stay warm? It would seem to me that would be a significant downfall to using such underwear. I know the Weezles have this reputation.

I've got some Thinsulate Diving Concepts stretch undies that I swear by - flexible, warm as all heck, and don't require loft to stay warm. They also stay warm when they're wet, too.

 

[JDostal]

I'm using some older stuff, a brand called Polar Bear. It's Thinsulate.

(Most) Every insulating material on earth requires some amount of loft. Down, thinsulate, fleece..that's how they work. They trap air, the trapped air stays warm and then keeps you warm.

If you squish the insulation too much, it can't trap air and you get cold.

I don't nee a ton of air in my suit. Just enough so the insulation isn't compressed too much.

 

[cdennyb]

I read the posts above with great interest. It seems I have a slight leak problem that I can't put my finger on as yet. I only use my BC on the surface.
I have a neoprene dry suit and dive like everyone else. This past few weeks I was up at 5200' elevation in a cold fresh water lake and the first dive was fine, I got a little wet 'ring' 1" around my tee shirt collar, nothin else.
Well that's no big deal, I can live with that. The depth was around 90' and I hit the inflate about 3-5 times to get the suit to quit squeezing me so damn tight. I would'nt say I had a lot of air in there by any means. The neck seal is in perfect condition as well, no tears, chips or rips.
Now the weird part...
The next day I went to around 30' for 30-35 minutes with my kids just puttin' around the stumps and rocks looking for fishing tackle and anchors and got hella wet! All the way to the thighs. I know it came in around the neck seal but I only hit the inflator about 1-2 times to take off the squeeze at most. The neck seal was the big culpret again as well.
I fold about 1-2" of the neck seal inward (you can't fold it outward or it don't seal) and I'm thinking I should've used more air to inflate and get a better seal with, am I right or what?
I can do the exhale sink, inhale float thing at the surface as well, so maybe I need more weight and more air too to stay dry.
any thoughts guys?

 

[Gary D.]

I'm seeing a lot of Neoprene reply's here. We went to shells around 15 years ago. My wife is in a Neoprene suit. With them you don't need any underwear at all or very little. With a shell you need it.

It also doesn't matter how big or small your neck or wrists are it's how they are shaped. If you bend them around and don't create any channels you get a better seal than those that have very pronounce channels in the muscles.

Also there is so little air in the suit, just enough to keep the undies fluffy (PT200) which aren’t that thick. I don’t get a floating bubble I have to worry about.

If your in a shell suit and don’t add any air why spend the money for the valves. A water ski dry suit is a lot cheaper and made from the same material.

Gary D.

 

[JDostal]

Yep - just enough air to fluff things up.

And I don't see how people can go down to 80 feet without adding air, unless you start with a TON of air in the suit.

I tried to see how deep I could go without adding air once. At 50 feet, I was getting pinched everywhere (including a hell of a sensitive spot...) like I couldn't believe, and things were SO tight that I was having a hard time moving my arms to my chest to hit my inflator.

Not an experience I would regularly do!