Should drysuit be used as a BC device?

[ScoobieDooo]

I just purchased my first drysuit and have been reading the drysuit course manual (SSI) prior to attending my course.

What I am reading seems to be saying that one should use their BC only on the surface for buoyancy control and the drysuit UNDERWATER for buoyancy control.

Now I know their are two sides of the fence on this issue, but somehow this practice doesn't sound right to me.

Isn't the key to drysuit diving to keep just enough air in the drysuit from getting squeezed?

I'm confused. What’s DIR's stance on this practice?

 

[Nessie]

Hi,

I have no clue about DIR´s stance, but my thoughts are:

-when you only use the drysuit for buoyancy underwater it might be a little bit easier because you can react quickly because you know immediately where you have to put air in/let air out.
Let´s say you suddenly realize that you are positively buoyant: you only have let the air out of your suit because you know your BCD is empty. Whereas if you use your BCD underwater you might try to deflate your BCD and realize that is empty and then have to let air out of your suit, this will take more time.
And another plus is that you have both hands free while you let the air out of your drysuit.

But:
-most times you can inflate/deflate your BCD faster than your suit.
-more air in your suit has a higher risk of too much air at the legs
-less exchange of air in your suit keeps you warmer.

With my first drysuit I used the "drysuit only"-method, but when I got my new one, the "air-out-valve" (sorry, don´t know the English term) was a lot slower and it fits less tight than the old one and I changed to the "mainly-BCD"-method.

 

[Irishdiver]

Hi ScoobieDoo: you aren't going to get agreement on this, different folks do their own thing and swear by the system they favour.

I know nothing about DIR. However, my thoughts are:

1. The BCD is designed to provide buoyancy compensation and to lift a diver to the surface. That's its sole purpose in life.

2. The dry suit is designed to keep the diver dry. That's it's sole purpose in life, though it's often not particularly good at that.

3. As a nice afterthought, the manufacturers have provided a low pressure inflation valve on the suit to counteract squeeze. That's its sole purpose in life.

4. Notwithstanding the above, some divers use the suit inflation as their primary source of buoyancy control and regard the BCD as an optional extra.

5. Most divers will agree that it's vital to keep the system as simple as possible to avoid the potential for screw-ups.

6. Following on from the last point, since you have to put air into your suit anyway to relieve squeeze, some will argue that it's better to use only that system for buoyancy during your dive.

7. From personal experience, I find that my suit can vent air through the seals (and let the damned water in!) depending on how I move in the water. This, coupled with the fact that the suit is not primarily designed to lift a diver, in my opinion makes it suitable only as a secondary source of buoyancy.

8. There are other opinions out there. You'll have to make up your own mind.

ut:

 

[chickdiver]

Scoobiedoo-

The drysuit should NOT be used for bouyancy, unless there is a failure of the wing (BCD). The diver should maintain only enough air inthe drysuit to prevent squeeze. The problem with using a drysuit for bouyancy is that it is sucha a large air cell, with the potential for such a large shifts in the placement of the gas, that it is extremely difficult to control, with real potential for a runaway ascent. I am very surprised that an agency is advocating this practice, which, in my opinion, is dangerous to a fault.

 

[ScoobieDooo]

I agree and plan to use ONLY my BC to control my buoyancy.

 

[MikeS]

Why does PADI teach using the drysuit for buoyancy? When I took the class I asked the instructor if he used his drysuit for buoyancy. He said “no but that’s the way that PADI teaches it, You probably wont either after the class, but for the class that’s the way you’re supposed to do it. Anyone know why, there must be some reasoning?

Mike

 

[detroit diver]

MikeS once bubbled...
Why does PADI teach using the drysuit for buoyancy? When I took the class I asked the instructor if he used his drysuit for buoyancy. He said “no but that’s the way that PADI teaches it, You probably wont either after the class, but for the class that’s the way you’re supposed to do it. Anyone know why, there must be some reasoning?

Mike

'Cause if they didn't they couldn't sell you a drysuit class, could they???

 

[Nessie]

They could at least I can sell a speciality teaching both ways.

 

[taat2d]

I just purchased my first dry suit, and am looking into taking a dry suit course too. I called a shop, and when I spoke to the instructor he told me that he teaches the course to use your dry suit for bouyancy. I told him that I was told by most that you're only to use enough air to get the squeeze out of your suit and to use your BC for bouyancy, and he told me that using the dry suit is the better and easier way to control bouyancy. Having not dove dry yet, I would think that I'd rather use my BC for what it's made to do and my dry suit to keep me dry.

 

[ScoobieDooo]

taa2d,
I agree...WHY would you intentionally want to introduce more air than is needed to prevent squeeze and risk being INVERTED during a dive...just seems foolish to me to add an unsafe factor into an equation...

I don’t know, maybe its ME?