Diving Dry

[BradJ]

I was taught to use my drysuit for buoyancy control in place of my BC.
In reading the GUE tech text a statement is made on gas supply/management that refers to the assumption that back gas is not used for suit buoyancy control.
Am I doing it wrong?

 

[Laser]

I was taught to use my drysuit for buoyancy control in place of my BC.
In reading the GUE tech text a statement is made on gas supply/management that refers to the assumption that back gas is not used for suit buoyancy control.
Am I doing it wrong?

Yes, you are doing it wrong. Search on this issue antd you'll see a heated debate in both camps.
Bottom line....BC is for buoyancy control, and suit is for warmth. There are times, when perfectly weighted, that the amount of gas in the suit is the correct mount to achieve neutral buoyancy. This is more likely when the tank is not full. Otherwise, alleviate the squeeze in the suit, and use the BC for the remaining adjustments. Last thing you want is a ball of gas shifting around in the suit which is what will happen at the onset of the dive when the greatest amount of gas is needed to acheive neutral.

 

[sheck33]

For the longest time i used my suit for bouyancy control, things got so much easier when i stopped doing that. Use the suit for what it is meant to be used for.

 

[mempilot]

Yes, you are doing it wrong. Search on this issue antd you'll see a heated debate in both camps.
Bottom line....BC is for buoyancy control, and suit is for warmth. There are times, when perfectly weighted, that the amount of gas in the suit is the correct mount to achieve neutral buoyancy. This is more likely when the tank is not full. Otherwise, alleviate the squeeze in the suit, and use the BC for the remaining adjustments. Last thing you want is a ball of gas shifting around in the suit which is what will happen at the onset of the dive when the greatest amount of gas is needed to acheive neutral.

Right on. Gas shift makes position control difficult if not impossible. That's why we dive with the smallest BC/Wing bladder possible for our lift needs. I see people wearing gators and wonder if they are using the suit for a BC and they are trying to keep the big bubble out of their boots. Using the technique described by Laser alleviates the need for gators, ankle straps, etc... The DS can be used as a backup BC when deeper in the event of a bladder puncture, but you'll be starting back to the surface and won't need it as you get shallow. Remember, neutral with no air at 15' and you should be able to swim your rig up.

 

[scubasean]

I was taught to use my drysuit for buoyancy control in place of my BC.
In reading the GUE tech text a statement is made on gas supply/management that refers to the assumption that back gas is not used for suit buoyancy control.
Am I doing it wrong?

I read the previous responses and wonder if your question is also about "assuming I use the suit however I do, what gas do I use to do that with?".

(For the record, I also use the B/C for buoyancy, and use the DS for warmth.)

As for which gas to use, some folks use Argon in a second tank for their suits...And some use air, from their main tanks, if air is what they are using to breathe.

Many who use Argon for the suit do so because they are using a mix other than air in their tanks...If they are using Helium in their mix, they use Argon in order to get better warmth than the Helium would provide. Helium allows more heat transfer away from the body than does air and argon, so when you use a helium mix, you want to use a separate tank to provide to your suit.

 

[grouchyturtle]

I just did Drysuit and Nitrox together last month. It was a pretty big class. About 10 of us, all who do a lot of diving locally, and all who spend way to much time on this board.

It was pretty funny during the drysuit part part of the class, when we got to the part about using the suit for buoyancy. Our instructor, was almost afraid to talk about it. I think his exact quote during the review was "We may have to spend some time on this next question. The answer may cause some controversy!" He knew most of us, even never using a drysuit, knew to use the BC for buoyancy.

Any way he explained a few reasons, why it's taught that way, but then told us of course no one really dives that way. So my first 2 dives in a drysuit, for the class I dove using the suit, actually had to do a few of those skills for real (too much air in legs! The next day went to the site again just to dive, and switched over to the BC. Ahhhhh, much better!

 

[MXGratefulDiver]

I actually got pretty good at buoyancy control using my DS ... but also learned that it's not the optimal way to do it.

Lots of people learn to use their drysuit for buoyancy because that's how many drysuit manufacturers recommend it be done. When I got my Diving Concepts suit, their owner's manual says only use your BC on the surface, and use your suit for buoyancy control.

But you run into limitations diving that way when you start getting into deeper dives, diving with doubles, or just going back to a wetsuit (having gotten out of the habit of using your BC for buoyancy).

After doing a few hundred dives using my DS for buoyancy I decided to try using the wing ... and it really does offer better stability. It's also easier to orient yourself in just about any position without having to worry about losing air out your dump valve.

... Bob (Grateful Diver)

 

[MHK]

Brad,

I'd like to add a few thoughts to this thread. Let me start out by saying there isn't a "right" way versus and "wrong" way. What there is, is a "more efficient way" versus a "less efficient way". All too often people get hung up on buzz words such as "right" -v- "wrong" and then the debate gets sidetracked and turned into a circus over "right" -v- "wrong"..

That being said, most drysuit manufacturer's and several prominent agencies will teach or recommend that you use your drysuit as your primary BC, see the DUI manual and PADI drsyuit course. We disagree with that for several reasons and we believe the analysis to use the dysuit over the BC doesn't go far enough in terms of it's research to get to their conclusions.

First off, look at the design of a wing. A properly designed wing is designed to compliment a diver who is in the proper position, ie; it wraps around the tank and when inflated allows for the air to be above the diver and the weight. Think of basic engineering principles, for example; if you were going to design an object to float in the water like a Zodiac, would you want air up and weight down or weight up and air down??? Obviously you'd want the air up and the weight down. That is why a BP and wing set up is more efficient then a jacket style BC. So with that in mind, think of a diver in a prone position, he has the wing with the air up, with the weight of the tank and the BP beneath the air. Good design from an engineering prosepctive, whereas a diver using a jacket style has the air below the diver and the weight of the tank above the diver, bad design from an engineering prospective.

Once you establish that principle, then follow the logic in using a drysuit -v- a BC. Air is dynamically instable, meaning that as a diver moves and changes position the air will constantly move. For example if you put your head all the way down to look under a reef, the air would go to your feet.. If, for some odd reason, you were completely vertical the air would go to your shoulders.. So ask yourself this question, do you want a dynamically instable air cell that is approx. 6' [ ie; you in a drysuit], or would you rather have a dynamically instable air cell that is much smaller in size [ ie; the size of your wing] and is contained in a cell [ your wing] that is designed to compliment your position in the water???

Obviously, once you think the issue through the answer is self-evident.

The only amount of air that you want in your drysuit, is the amount that it takes to re-establish the loft of your undergarment to allow for full insulating potential. Any more then that is a waste and can result in improper balance and trim..

Hope that helps, but if not feel free to follow up..

Regards

 

[SoScuba]

I have gotten into the practise of using my suit for bouyancy and only minimally using my wing. For my set I find that I don't have to have an over abundant amount of air in my suit for neutral bouyancy at depth. One of the advantages I find to using the suit is the ease of ascending from a dive. I simply adjust my suits deflate valve to the right setting and i allow it to automatically vent as I ascend. Maybe its the lazy way. However that being said, I have been noticing myself "fighting" with my positioning in the water and after reading MHK's posting above I see where my problem lies. I plan on adjusting my technique acordingly in the future and see what happens.
Thanks!

 

[Scubakevdm]

Brad,

I'd like to add a few thoughts to this thread. Let me start out by saying there isn't a "right" way versus and "wrong" way. What there is, is a "more efficient way" versus a "less efficient way". All too often people get hung up on buzz words such as "right" -v- "wrong" and then the debate gets sidetracked and turned into a circus over "right" -v- "wrong"..

Hey! That's pretty good. So it should be DIME, not DIR.