No BC w/Dry Suit?

[finster]

I have been diving very comfortably w/my drysuit (DUI TLS350) for the past year. In the meantime, my 11 year old Sea Quest Quickdraw weight integrated BC is about ready for retirement.

I was thinking that perhaps it would be a good idea to buy a tank harness and a nice soft mesh weight belt and entirely use the drysuit for bouyancy control rather than spending $500 on a new BC that essentially only gets used for buoyancy on the surface.

Should I forego the BC purchase? Is this what most drysuit divers end up doing?

Any opinions would be greatly appreciated?

 

[Uncle Pug]

Well finster... have a go with this story:
http://www.scubaboard.com/showthread.php?s=&threadid=7551

It probably involves a dive site and equipment that are not a consideration for you but it might help you see a need for a good wing or BC...

It is one thing to be able to swim the rig up with a total flood (in my case in the above cited story this would have been an impossibility).... but would you be able to keep yourself up... especially with a cold water flood?


Another issue I would like to take on is the proper use of a BC or Wing with the drysuit:

BC that essentially only gets used for buoyancy on the surface.

Unfortunately many are taught that this is the correct way to dive a drysuit... in fact I think that DUI even recommends this in their little booklet that ships with suits.

I would advise that you only put enough gas into the suit on descent to alleviate excessive squeeze and avoid having a bubble of gas in the suit. Compensate for buoyancy shift from full to empty tank by using (of all things) the aptly named "Buoyancy Compensator." We dive with our automatic suit dump valve in full counter clock wise open position.

This will allow you to take weight off of your belt/rig as well as maintain better control of your buoyancy change during ascent. Another feature of diving this way is that you avoid the drag created by a billowing suit and the extra energy expenditure necessary to swim that bag of gas around.

But avoid excessive squeeze... I'm not suggesting getting suit hickies here... just put enough gas in the suit to allow full range of motion for the arms (tank valve drills.)

A good starting point is to walk out into the water (Assuming a shore dive in this instance) with your neck seal held open and allow the water pressure to squeeze out the excess air. Then gear the rest of the way up and dive... adding small squirts of gas to maintain the comfortable hug of a loving drysuit.

 

[metridium]

Originally posted by Uncle Pug
Unfortunately many are taught that this is the correct way to dive a drysuit... in fact I think that DUI even recommends this in their little booklet that ships with suits.

To put it mildly...

From the DUI Dry Suit Manual, p. 33:

"WARNING: Do not inflate your buoyancy compensator under water while using your dry suit. Controlling two independent air bladders (the BC and the dry suit) is a very difficult skill to master. If not carefully performed, you may experience a rapid and uncontrolled ascent....

The only occasion on which you should even consider inflating your buoyancy compensator under water is if your dry suit is damaged and unable to hold air."

That's a major disconnect between what DUI says and what GUE teaches, if I'm not mistaken. Wonder if that could cause any liability issues for GUE or other tech agencies teaching simultaneous usage?

 

[SubMariner]

Should I forego the BC purchase? Is this what most drysuit divers end up doing?

No drysuit diver dives without a BC, for many of the reasons that have already been discussed. Not the least of which is keeping afloat at the surface. In order to be totally positive at the surface you would have to pump so much air into your suit you wouldn't be able to move. Not a good idea.

Buoyancy control underwater seems to be personal preference: some Instructors/agencies teach using the suit for buoyancy control underwater and the BC only at the surface; while others teach only putting enough air in the suit to avoid squeeze and maintaining buoyancy control with the BC.

Frankly, I'm with DUI on this one. I teach u/w buoyancy with the suit and leaving the BC for backup and/or to maintain positive buoyancy at the surface. It just seems to make more sense to have to manage only ONE airspace underwater rather than two.

Again, mostly a matter of opinion.

~SubMariner~

 

[doll_fins]

I took a drysuit certification course (new diver so I thought that would be best!) and they told me to absolutely NOT use the drysuit for bouyancy!

Like UP said, I was taught that you add enough air to the suit to take off the squeeze, but all bouyancy control comes from the BC (and as a new diver I am still adjusting fairly frequently!). I don't think it is difficult to manage both since I don't really do much with the drysuit other than release air as I ascend.

I also heard that using the drysuit for bouyancy wears the seals out faster.

 

[metridium]

Originally posted by doll_fins
I took a drysuit certification course (new diver so I thought that would be best!) and they told me to absolutely NOT use the drysuit for bouyancy!

Which agency was that through?

In the PADI class rolleyes:, I know, I know!) I took, we were taught to use the drysuit only. It was quite interesting trying to dive overweighted and with the dump valve set to manual.

 

[Uncle Pug]

On the one hand you have DUI... people whose expertise is sewing & gluing stuff together...

And on the other hand you have GUE... people whose expertise is training cave and technical divers...

whom to follow... whom to follow...

Keeping as much gas out of the suit as practical short of squeeze is an important part of controlled ascents.

Keeping as much gas out of the suit as practical short of squeeze is an important part of streamlining.

Keeping as much gas out of the suit as practical short of squeeze is an important part of reduced effort of swimming.

Keeping as much gas out of the suit as practical short of squeeze is an important part of acheiving and maintaining correct trim.

Folks who cannot control their suit and wing at the same time probably can't control their suit by itself.

As for whom to sue... that is up to you... but consider:

Which is the most likely scenario... a DUI trained drysuit diver using his/her suit for buoyancy compensation suddenly broaching the surface having missed the 15' safety stop...

Or a GUE trained drysuit diver using his/her wing for buoyancy compensation suddenly broaching the surface having missed the last stop?

 

[metridium]

Originally posted by Uncle Pug
On the one hand you have DUI... people whose expertise is sewing & gluing stuff together...

And on the other hand you have GUE... people whose expertise is training cave and technical divers...

whom to follow... whom to follow...

Oh, I know whom to follow, all right.

I'm surprised you didn't mention the benefit of standardization and reflex memory in always using the BC, no matter the configuration.

 

[metridium]

I have to admit that the squeeze is surprisingly light in my current configuration of thinsulate and military-weight polypro, with the valve set to fully open. When I used to dive with ad hoc divewear and a rental drysuit, it was much worse. Odd.

Edited to add: Must have been over-dumping back then, since I was using manual dump instead of full auto-dump.

<end soliloquy>

We now return you to your regularly scheduled programming, already in progress.

 

[doll_fins]

Originally posted by metridium

Which agency was that through?

In the PADI class rolleyes:, I know, I know!) I took, we were taught to use the drysuit only. It was quite interesting trying to dive overweighted and with the dump valve set to manual.

SSI :boom: