Questions about Dual bladder wings

[danvolker]

That's where things could get dicey. A diver surfaces and quickly realizes that he is losing buoyancy. Reaching into a pocket or up under the plate for a buoyancy tool probably has not ever been practiced by the diver. If tired or if the seas are rough, or both, that might end badly. The diver in the GUE-F class had a bag, but never thought to deploy it as he called out, "A little help.... gurgle!"

Likewise, a second inflator could present the same issues if not practiced. However, most divers would much rather have a working BC rather than be hanging onto a bag in heavy seas. Fortunately, wing failures are rare and rarer still are wing failures with total loss of buoyancy.

On a side note, instructors need to be careful about teaching drysuits as buoyancy devices from a legal perspective without checking to see if the drysuit manufacturer intends for the suit to be used as part of the buoyancy system. If a drysuit manufacturer states clearly that the suit is not intended as a buoyancy device, then that could open up a can of worms. That's actually the reason why some agencies state that a dual wing is required in their standards - so that instructors don't open that window of liability in which they advocate that a device be used in a way that wasn't intended. The same goes for liftbags and DSMB's.

And again, to me it is irresponsible for an Agency to put baby tech divers in heavy steels that WILL mean they will be dangerously negative if a wing problem occurs. Much smarter would be to mandate a balanced rig( meaning you don't need the wing to swim it up)...then, someday, when they have loads of experience, they can re-think dragging much more gas with them. I still don't get why a tech diver in ocean needs more than 25 minutes at 280---meaning why they can't get by with Al80's rather than big heavy steels. If the breathing rate is too high to get close to 25 minutes of BT, then probably the diver needs 100 more dives to work on slickness and efficiency and low heart rate, before they should be doing the deep dives. Also, after 20 or 30 deep dives with the balanced rig, the new tech diver will probably figure out this is a much smarter way to go, and the problem goes away with the heavy cr*p.
Of course, the balanced rig mandate would cost dive shops selling TECH, loads of income, because the steels are 2 and three times as expensive at aluminum 80's, and with the full gas loads, they get to sell a 4th regulator. The same shops would be horrified to hear that divers don't need to throw away the money on the dual bladder wings, and that would mean that if they want to try and eek out big money from tech, they would have to shift to selling Closed Circuit Rebreathers I knew when PADI got in to the tech business, there would be unfortunate ramifications....the money train and expedience being the worst.



***Note--this is not PADI Bashing, per se. While I was certified NAUI in 72, and mentored by GI of WKPP for tech, and taken Fundies by GUE.... I recently did the PADI DM course because I needed it for a program we have for getting non-divers an underwater Experience--and then from the PADI DM, I got an Instructor rating for the Tooka through NASE.... I will say that the PADI Rescue and DM classes were top notch, and I think the agency did a great job with the material and required skills for these classes. However, when they moved into the tech arena, they kept the PADI OW1 mindset of trying to make the classes fit the largest number of divers--to open this up to as much income as possible. That is NOT the right way to go for tech diving, or cave diving.

 

[Trace Malinowski]

I don't advocate the use of heavy steel tanks. But, if you read the standards of various agencies some will say that a dual wing is required for any twin steel tank such as 85's.

 

[PfcAJ]

Agencies. Well known for their good ideas

 

[Trace Malinowski]

Lawyers. They like things that look good on paper.

 

[rjack321]

Lawyers. They like things that look good on paper.

Dual bladder wings look good on paper.

 

[TSandM]

Using a drysuit as the redundant buoyancy system to overcome the prevailing large negative buoyancy as you ascend into and hold your deco stops is a fairly advanced skill that will be a challenge to master while simultaneously learning all the new skills of the tec course.

Why would any reasonable person begin a technical class with equipment that was entirely new to them? That's a recipe for not having a good educational experience. If you have reasonable facility with a dry suit, using it to compensate for loss of wing lift is not that complicated.

 

[rlynch]

Thanks for the insight on twin bladders, still not seeing a place in my quiver for it though.
I doubt 90% have inflated them other than at the surface at home. At least up here anyway. So it's a false security in most cases.

Ill stick to dry suit and wing. Something I practice and dive with all the time.

Good point on most folks not practicing pulling out and shooting liftbags and such from the bpw pocket. Mist don't if they have anything there at all.

Btw, lp85's are what I choose for ocean and wet diving, I can and have swum them up from 100 fsw, with no wing, waited for divers to clear the lift at the surface and fixed the issue with full tanks.
I put them in the same as al80 category for weight personally. But that's me.

 

[DogDiver]

I cave dive side mount 120's often carrying an AL 80 stage plus an AL 40 with O2 for deco. I dive with wet suit. My typical dive is usually at110 feet for an average run time of 90-110 minutes. No problems with hypothermia. I do switch to my backup air cell about every 5th dive just to train my memory to switch inflators without light. After I punctured an air bladder at Hart, I purchased a duel bladder Nomad.

 

[LiteHedded]

I cave dive side mount 120's often carrying an AL 80 stage plus an AL 40 with O2 for deco. I dive with wet suit. My typical dive is usually at110 feet for an average run time of 90-110 minutes. No problems with hypothermia. I do switch to my backup air cell about every 5th dive just to train my memory to switch inflators without light. After I punctured an air bladder at Hart, I purchased a duel bladder Nomad.

wouldnt it probably just puncture both of them?

 

[DogDiver]

The redundant air bladder is under the primary bladder. It would take a significant sharp object for you to strike into, epically side mount to puncture 1000 denier plus two bladders. If that did happen, one has more to worry about at that point than buoyancy. Lol.