Double bladder question

[MaxBottomtime]

From GUE's webpage;
Many divers mistakenly believe that they must have large buoyancy compensators to support their diving needs. Actually, divers do not need excessive amounts of lift; large wings, because of the additional material they require, only serve to increase drag. However, if a diver does need more than 65 pounds of lift for diving doubles, or more than 30 pounds for diving singles, then they do not have a balanced rig. The diver should be able to drop unnecessary weight and swim up without a functioning BC. As with all diving, the key component to proper buoyancy is diving with a properly balanced rig.
Divers using dual BCs have experienced an array of problems including increased drag, additional task loading and uncontrolled inflation. There is never a need for redundant buoyancy in a properly balanced rig. The DIR approach avoids the use of dual BCs, and instead stresses proper balance between BC, cylinders, weighting and exposure suit.

 

[Reg Braithwaite]

with 5lbs of lift from my suit

Is there really only five pounds of lift in a dry suit? I have a White's Fusion. I seem to recall diving a steel 95 and 8 lbs of weight using only the dry suit for buoyancy in Brockville. Was I hallucinating from heat exhaustion?

 

[ianr33]

5lbs is the decrease in buoyancy of an Al 80 during a dive (6 lbs if you breathe it totally empty)

So the drysuit would have 5lbs MORE buoyancy at the end of a dive compared to the start, if it was used for buoyancy compensation instead of a wing.

Total lift of a drysuit is way more than 5 lbs.

 

[dumpsterDiver]

... If the dive is deep, you're going to be in deco. If the dive is shallow but long, then thermal protection is going to be warranted. So the correct answer is to wear a drysuit. And along with that comes redundant buoyancy.
.

Is this really the DIR answer? I would think that there are many places and situations were a well fitted wetsuit will provide more than enough thermal protection and it is a lot less likley to suffer a catastrophic failure that would render it incapable of providing bouyacy and thermal protection?

 

[amascuba]

Is this really the DIR answer? I would think that there are many places and situations were a well fitted wetsuit will provide more than enough thermal protection and it is a lot less likley to suffer a catastrophic failure that would render it incapable of providing bouyacy and thermal protection?

Thicker wetsuits will compress at depth, which will make them less buoyant and inefficient at providing thermal protection over a period of time. The worst of both worlds.

The thermal protection in a drysuit comes from the undergarments. The undergarments should be made of a material which wicks moisture away from the skin. There is a post floating around somewhere where Blondie had a drysuit flood during a dive and was in the water for four hours with a flooded suit and managed to finish the dive with little noticeable loss of heat. Bottom line, it's all about the undergarments as far as drysuits are concerned. You don't have that option with wetsuits.

 

[TSandM]

I don't understand the proposed issue with using the dry suit for buoyancy. I dove tonight with full 85s, properly weighted, and used my drysuit exclusively, without any trouble at all. In fact, I haven't touched my wing in a while . . .

 

[Big Toes]

hey all:

thanks for all of your great replys. for those of you that replied with real, actionable information; i am grateful. for those of you that thought that i was just 'trying to get noticed' or trying to start an argument; you really read me all wrong. i was looking for info!

and for that last segment of the population here that thought i was picking on them; i apologize if you're really that sensitive. no harm was intended, and i sure hope you didn't take it that way.

lastly, somebody here made the inference that i had something to do with the saltwater/freshwater buoyancy issue: not sure where you got that, but it wasn't me.

couple of notes:

-gear was borrowed, so i had to deal with what i had on hand
-yes, it was an 85# wing which i realize is huge! again, borrowed gear.
-my instructor, i think, was TDI certified

so for better or worse, i thank you all for your input. after spending 11 years with us navy specops i'm still wondering what the major trauma/difficulty is with the 'fundies' course, so please let me know if either i or my instructor missed something.

erik

 

[PerroneFord]

-my instructor, i think, was TDI certified...

i'm still wondering what the major trauma/difficulty is with the 'fundies' course ...

...so please let me know if either i or my instructor missed something.

The only thing you and your instructor missed was an actual fundies course. Not sure what you spent your money on, but it wasn't fundies.

 

[Gombessa]

Wow. #7 ftw.

 

[nadwidny]

lastly, somebody here made the inference that i had something to do with the saltwater/freshwater buoyancy issue: not sure where you got that, but it wasn't me.

http://www.scubaboard.com/forums/3615715-post200.html