Your thoughts on dual bladder wing

[doctormike]

I use a double bladder wing when diving wet with doubles. It's pretty rare that I am in a configuration that would require this, but it's a good thing to have when I am.

It is a simple, cheap ($90), elegant solution to the remote possibility of a wing failure early on in the dive with full tanks leading to an uncontrolled descent. It adds absolutely nothing to the rig (the extra inflator is tucked away neatly, and of course not connected to an LP hose). It is MUCH easier to just orally inflate the backup wing than to start deploying a lift bag during an emergency.

I'm really not sure why these things have such a bad reputation in certain circles, other than the implication that you haven't balanced your rig, I suppose.

 

[PfcAJ]

The idea of that scares me a lot more than the idea of jumping in and pulling my inflator elbow off. At the point I realize my gas is off, I could have just done a full exhale and might only have 30 seconds before I can't help gasping and inhaling water. Probably less given the possibility of it making me panic. Jumping in with my gas off scares me more than any other problem I ever think about.

But, as long as I can breathe, the lost elbow is something I can deal with. Even if I drop to 200', how big a deal is that? It's not like I'll incur a big deco obligation during the time I'm there. And my tanks are full, because it's the start of the dive. The only major problem I would foresee is if I were diving with a gas that gave me an MOD I was worried about busting. But, my MOD is normally going to be deeper than the bottom anywhere I'm diving, so it wouldn't be an issue.

It might be a big deal if you're diving a wall.

I just don't get the reluctance by some to dive a balanced rig. Is it that hard for folks to do?

 

[stuartv]

I just don't get the reluctance by some to dive a balanced rig. Is it that hard for folks to do?

Who is reluctant to dive a balanced rig? Balanced rig is the same thing most of us mean when we say "properly weighted", right? I.e. neutral with an empty wing and empty tanks.

Are you suggesting that having a balanced rig is always the only thing you need to have in the event of a catastrophic wing failure?

When I do a deco dive, I will start the dive over 20# negative (double 120s plus an AL40). If I were doing that in a 7mm wetsuit, I could be well over 30# negative at the bottom - but that's still a balanced rig, right? I feel like, if I were doing that for some reason, I would want to have redundant buoyancy.

Side note: My question reminds me of another question I've wondered about. People always say you should never dive double steels in a thick wetsuit. The implication is that double aluminum tanks is okay. So, why is double AL100s better than double HP100s? If you're diving in a 7mm wetsuit, you should have no trouble achieving proper weighting (i.e. a balanced rig), right? So, either way you'd be starting the dive negative by about 16# (with double 100s). So, why does it matter if the tanks are steel or aluminum?

 

[PfcAJ]

Who is reluctant to dive a balanced rig? Balanced rig is the same thing most of us mean when we say "properly weighted", right? I.e. neutral with an empty wing and empty tanks.

Are you suggesting that having a balanced rig is always the only thing you need to have in the event of a catastrophic wing failure?

When I do a deco dive, I will start the dive over 20# negative (double 120s plus an AL40). If I were doing that in a 7mm wetsuit, I could be well over 30# negative at the bottom - but that's still a balanced rig, right? I feel like, if I were doing that for some reason, I would want to have redundant buoyancy.

Side note: My question reminds me of another question I've wondered about. People always say you should never dive double steels in a thick wetsuit. The implication is that double aluminum tanks is okay. So, why is double AL100s better than double HP100s? If you're diving in a 7mm wetsuit, you should have no trouble achieving proper weighting (i.e. a balanced rig), right? So, either way you'd be starting the dive negative by about 16# (with double 100s). So, why does it matter if the tanks are steel or aluminum?

No, that's not a balanced rig.

Enough weight to say at 15' with empty tanks
Light enough to swim up if your wing breaks
If you can't swim them up, wear a drysuit

Double al100s (I wouldn't recommend those anyways but whatever I'm here for the conversation) aren't nearly as heavy as double steel 100s.

According to this chart (which seems reasonable) a luxfer al100s is -4.3lbs full while a pst 100 is -8.5lbs. Thats a big difference. Like almost double.

 

[PfcAJ]

duplicate

 

[stuartv]

Double al100s (I wouldn't recommend those anyways but whatever I'm here for the conversation) aren't nearly as heavy as double steel 100s.

What difference does that make? Once you're weighted to be neutral with an empty wing and empty tanks, then you're going to start the dive negative by the amount of gas you're carrying. So, you'll be the same negative whether you have double AL100s or HP100s. It doesn't matter whether you have AL100s and 12 pounds of lead on your belt or HP100s and 4 pounds of lead. You're still roughly 16# negative at the start.

That said, I do now understand that Balanced Rig means properly weighted AND enough of your weight ditchable that you could swim it up. Correct?

So a 7mm wetsuit and double steels COULD mean that you'd be on the bottom and not actually be carrying enough lead to ditch to be able to swim it up (because the tanks themselves represent a fair bit of unditchable negative ballast). But, aluminum tanks would require enough extra lead that, as long as it's ditchable, you could swim it up.

 

[PfcAJ]

What difference does that make? Once you're weighted to be neutral with an empty wing and empty tanks, then you're going to start the dive negative by the amount of gas you're carrying. So, you'll be the same negative whether you have double AL100s or HP100s. It doesn't matter whether you have AL100s and 12 pounds of lead on your belt or HP100s and 4 pounds of lead. You're still roughly 16# negative at the start.

That said, I do now understand that Balanced Rig means properly weighted AND enough of your weight ditchable that you could swim it up. Correct?

So a 7mm wetsuit and double steels COULD mean that you'd be on the bottom and not actually be carrying enough lead to ditch to be able to swim it up (because the tanks themselves represent a fair bit of unditchable negative ballast). But, aluminum tanks would require enough extra lead that, as long as it's ditchable, you could swim it up.

I think you're on the right track now.

 

[The Chairman]

Glad to see you haven't died yet Pete,I didn't either when I've dove them.Despite their ferocious reputation for unplanned mayhem.I did have 2 LP hoses--primary long,secondary short on the same shoulder.

Now I mostly dive 18 to 23# wings wearing a 120 and carrying about 10 pounds of spearfishing gear,a SS STA and BP.I gave up the long hose as I prefer diving solo.

I even punctured the BWOD on a sharp projectile in a real wreck. Tore me up too, so there's no way a dry suit would have survived that wreck.

Light enough to swim up if your wing breaks
If you can't swim them up, wear a drysuit

Or, you have a second bladder in your wing.

What? You can't get your mind around that? That's OK, a number of us don't find ourselves over our collective heads with the logic. Redundancy, no matter how you employ it, is still redundancy. I don't like dry suits, so I don't wear dry suits. You don't like double bladder wings, so don't use them. Either way, we're just as 'balanced' and we're just as redundant.

 

[PfcAJ]

I even punctured the BWOD on a sharp projectile in a real wreck. Tore me up too, so there's no way a dry suit would have survived that wreck.

Or, you have a second bladder in your wing.

What? You can't get your mind around that? That's OK, a number of us don't find ourselves over our collective heads with the logic. Redundancy, no matter how you employ it, is still redundancy. I don't like dry suits, so I don't wear dry suits. You don't like double bladder wings, so don't use them. Either way, we're just as 'balanced' and we're just as redundant.

Again, Pete, a dual bladder isn't going to stop you from lawn darting to the bottom if the elbow pops off when you jump in the water.

 

[CptTightPants21]

What difference does that make? Once you're weighted to be neutral with an empty wing and empty tanks, then you're going to start the dive negative by the amount of gas you're carrying. So, you'll be the same negative whether you have double AL100s or HP100s. It doesn't matter whether you have AL100s and 12 pounds of lead on your belt or HP100s and 4 pounds of lead. You're still roughly 16# negative at the start.

That said, I do now understand that Balanced Rig means properly weighted AND enough of your weight ditchable that you could swim it up. Correct?

So a 7mm wetsuit and double steels COULD mean that you'd be on the bottom and not actually be carrying enough lead to ditch to be able to swim it up (because the tanks themselves represent a fair bit of unditchable negative ballast). But, aluminum tanks would require enough extra lead that, as long as it's ditchable, you could swim it up.

Balanced Rig Check:

With air drained from drysuit and wing, hold a 10 ft stop for 2 min with 500 psi in your tanks.

With air drained from drysuit and wing, swim full tanks up from a depth of at least 30 ft to the surface.

Most divers wearing a 7mm and steel doubles wouldn't be carrying any additional weight.