Ok, so whilst waiting for my new (2nd hand) drysuit to have it's neck seal replaced I thought I would brush up on a bit of theory for drysuit diving as I realise it is very different from diving wet.

I have been reading Scubaboard threads on this and the argument seems to be between using your DS as your buoyancy control in totality (wing only when you require additional lift or using your BC as control and air in the DS only to remove squeeze and provide a little thermal protection.

So, what do people use here? Flipper is there a GUE practice? What has worked best for any of you?

Are there any other tips for best practice in a Drysuit? Feeling a touch nervous as my first DS dive could be on the PK trip and don't want to spend the entire time feet in the air completely inverted and thrashing around, or worried about being a one way rocket to the surface!

How is the best way to vent the air? raising a bent arm? tuck and roll?

thanks

Alex

I only dove a couple of times in my DS myself but I don't really see how one can only use DS for buoyancy control.
I tried that in the Lake and you know what happened.
Unless the right amount of air in my DS makes me neutral at the same time, I will need my wing for buoyancy control.

I would advise quite strongly against using your suit as bouyancy.
It may work if you are perfectly balanced weight wise but at the start of the dive you will need more air in your suit to counter the weight of the air in your tank (about 3kgs in a 12L tank).
This air is then free to roam around your suit where ever it wants. This will really upset your trim.

My advice is continue to use your wing as bouyancy, set the auto dump as low as possible so any excess air can escape with ease and just put enough air in your suit to avoid discomfort.
YMMV

The way I dive in a DS is only to ever put enough air to stop the squeeze from the DS. Then use the wing for bouyancy.

hint: think of you (the diver) as spirit level, and the bubble inside the level is the gas inside your suit.

So if the bubble is inside your feet then you'll be head down, and if the bubble is your neck then you'll feet down.

And of course the bigger the bubble inside the suit the more extreme the movement will be.

So the goal is to get as small as poss gas inside the suit, then to keep it in a position that promotes good trim.

Undersuit make a difference too. More 'lofty' the under suit the more air it holds, the more lead you'll need.

Also if you're planning on long deco stops, I'd overweight yourself a bit so you can handle a bit more gas in the suit, when sitting still during the long stops, otherwise you may get cold.

thanks for these - that's what I had thought would be best practice too. minimum air in the suit (just enough to keep squeeze off) then use the wing for buoyancy.
It's funny how there are people on http://www.scubaboard.com/forums/exposure-suits/231286-dry-suit-trouble.html
that are convinced that you should use the suit for buoyancy - and according to some Padi promote this (leaving out opinions on PADI!)

I'm very much in the wing for bouyancy, suit for warmth camp!

In line with all the above - I always prefer to only add air to the drysuit as a comfort thing. There are divers out there who use the DS as their primary buoyancy, but personally I'd never do this. It's hard to dump quickly from the DS, the air can move around in a second and catch you out. also, if you have excessive air and you go vertical, it'll probably 'autodump' out of the neck seal, giving an instant problem to deal (and when this happened to me it also dumped quite a bit of 8degree water into the suit).
The wing is for buoyancy, the drysuit is for protection to exposure.

Old thread I know... but thought I'd share my experiences.

I always thought I was firmly in the "suit for warmth, wing for buoyancy" camp, and up until a couple of months ago, that's the way I did things.
Well now I'm using my suit for 90% of buoyancy adjustments and loving it!

I'm warmer, and can make fine adjustments at any time without reaching for my inflater.
I'll add a couple of puffs to my bc early in my descent and maybe a couple more later if it's a deep dive, but as the dive progresses and I breath my tank down, that air will be dumped for good.

I find the only time I am running my suit a bit tighter now is if I need to swim down in strong currents etc or if I want to go inverted to look down a hole or something.

For small buoyancy changes I dont have a problem with this approach.
But it doesnt work too well when you put too much gas in the suit. It effects your trim to much with the gas moving around in the suit and its also easy to loose the gas out the vents.
But I do agree with you about it helping keep you warm. The less air in your suit the colder you will be.

When would you ever to make large buoyancy changes? Diving doubles maybe?
I have found that air comes out of my suit dump much more readily and much faster if there is a bit more in there.

If you have double 12L's you need to compensate for 6.7kgs air lost during the dive. That is a lot of air to put into a DS. Even half that ( single 12 ) is quite a bit.

In the end it is down to the user. But I think the way it should be taught is BC is for Buoyancy Compensation and Dry Suit for keeping you dry. If you decide to mix it up once you have your skills sorted ( many dives later) then that is fine.