Should drysuit be used as a BC device?

[MikeS]

detroit diver once bubbled...



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

I don’t think that’s it. I would have taken the class anyway for several reasons. First, the LDS threw in the class with the drysuit, so I didn’t pay anything for it directly. Secondly, it gave me a chance to practice in the pool where if anything went wrong I could stand up. Of course if you become inverted, a handstand is of dubious value.

There must be some reason! I suspect the philosophy is it’s easier to only have to worry about one inflator. But why teach bad habits that then have to be unlearned?

Mike

 

[mddolson]

Chickdiver bubbled: 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.

DEPENDS ON THE SUIT:
I wear a shell suit, so the material doesn't compress. Only the air in the suit compresses as I descend. Properly weighted I mearly add air to my suit as I descend, to compensate for the squeeze in the "bubble".
By doing this "I am using my suit as compensator", and I don't need to add additional air to my BC unless I was over weighted.

A neoprene suit squeezes in thickness as well as the internal volume.
A diver would have to add additioanal air to the suit to make up for this lost dispalcement. Depending on the fit of the suit this might over stress the seams. So air is usually required to be added to the BC rather than over inlfate the suit so to speak.

In an emergency (rescue ) situation, the Wing over inflated makes the victum unstable with a tendancy to float face down. In this situation , a combination of suit and wing inflation are reguired to keep the victim/patient is a stable face up postion.

Mike D
:blfish:

 

[ScoobieDooo]

Mike,
I SUPPOSE that it sure would be easier having to worry about ONE inflator than 2 - that’s a given - but in doing so, it can create a entirely NEW set of problems for the diver - being INVERTED! THAT sure can't be desirable!

 

[Nessie]

No, I do not think that the risk of being inverted has to rise much when using the drysuit for buoyancy.
First it depends on how the suit fits. With my old suit ( ;-0 ) I could dive with my head down for quite a long time before I felt the air move towards the legs.
Second why should you add so much more air when you use your suit for buoyancy? You only need so much weight that you are neutral when your suit has just as much air in it to feel comfortable
I do not think this method is so much more dangerous and I still miss the feeling of having both hands free all the time.
Both methods have pros and cons and that is the reason why a drysuit speciality taught by me contains both methods.

 

[Dryglove]

Read this http://www.baue.org/faq/dynamic_instability.html and this http://www.baue.org/faq/wing_size.html

 

[Nessie]

lal7176 once bubbled...
Read this http://www.baue.org/faq/dynamic_instability.html and this http://www.baue.org/faq/wing_size.html

Still find no reason why you have to put more air into your drysuit when you do the buoyancy with your suit???

 

[bwerb]

Nessie once bubbled...


Still find no reason why you have to put more air into your drysuit when you do the buoyancy with your suit???

]

...you are not putting MORE air into your suit than you do with a wing/bc, it is just "positioned" more optimally. With a BC you have a "ball" or "bag" of air positioned in more or less one place over your center of gravity. With a suit, you add the same amount of air but, it is not stable in it's position. As you move and shift during a dive the air "pocket" can go anywhere from down around your feet to up one arm. Each accompanying shift in this "sheet" of air will seriously affect your CG and you will be fighting the tendency to have a rapid attitude shift as it moves.

 

[Nessie]

bwerb once bubbled...
]

...you are not putting MORE air into your suit than you do with a wing/bc, it is just "positioned" more optimally. With a BC you have a "ball" or "bag" of air positioned in more or less one place over your center of gravity. With a suit, you add the same amount of air but, it is not stable in it's position. As you move and shift during a dive the air "pocket" can go anywhere from down around your feet to up one arm. Each accompanying shift in this "sheet" of air will seriously affect your CG and you will be fighting the tendency to have a rapid attitude shift as it moves.

Sorry, if I didn´t state clearly.
What I meant was that you can have more or less the same amount of air in your DRYSUIT when using the suit for buoyancy and when you only put air into it to feel comfortable, ist just about proper weighting. (At least as long as you are not diving a neoprene suit, but then the fitting will probably be tighter and the shift will be less.)

 

[detroit diver]

MikeS once bubbled...


I don’t think that’s it. I would have taken the class anyway for several reasons. First, the LDS threw in the class with the drysuit, so I didn’t pay anything for it directly. Secondly, it gave me a chance to practice in the pool where if anything went wrong I could stand up. Of course if you become inverted, a handstand is of dubious value.

There must be some reason! I suspect the philosophy is it’s easier to only have to worry about one inflator. But why teach bad habits that then have to be unlearned?

Mike

Actually, I was just kidding. I have no idea why they teach drysuit diving with the suit as bouyancy.

 

[Dryglove]

Nessie once bubbled...


Sorry, if I didn´t state clearly.
What I meant was that you can have more or less the same amount of air in your DRYSUIT when using the suit for buoyancy and when you only put air into it to feel comfortable, ist just about proper weighting. (At least as long as you are not diving a neoprene suit, but then the fitting will probably be tighter and the shift will be less.)

Depending on your tank your gonna have to offset about 6-10lbs of air in your tanks at the beginning of your dive assuming you are weighted neautral at the end of your dive with near empty tanks.Thats a pretty good size air bubble floating around in your drysuit.Its kind of like lying on a big ball trying to balance yourself on it.You got this air bubble floating into your arms, down to your legs and all over which makes proper trim very hard till the end of your dive when you have less air in your suit cause you have less weight of air in your tanks.Thats why a lot of people who use their drysuit for buoyancy have lousy trim at the beginning of their dive but gets better towards the end.