Redundant Bladders

[mikemikethepike]

What is the general feeling about redundant bladders?

I know that DIR specifies that the wind should not have a bungee and that it should not have "excessive" lift, but what about redundant bladders. I think I notice that the DIR folks tend to not have redundant bladders.

I understand that a dry suit can be used for redundant buoyancy, put I also read in the PADI Tech Deep manual that often you can be so negative that trying to maintain neutral buoyancy using a dry suit may exceed the capacity of the dry suit. Obviously, not a DIR diving is done with a dry suit anyway.

I guess that you might be able to use a lift bag or a SMB in the event of a wing failure, but I have not seen any evidence that this is part of DIR training?

What is the DIR contingency for wing failure and what is the feeling surrounding redundant bladders.

I have a pair of HP120's and a Dive Rite Super Wing (redundant). I believe that this wing has 77 lbs of lift.

 

[cool_hardware52]

What is the general feeling about redundant bladders?

I know that DIR specifies that the wind should not have a bungee and that it should not have "excessive" lift, but what about redundant bladders. I think I notice that the DIR folks tend to not have redundant bladders.

I understand that a dry suit can be used for redundant buoyancy, put I also read in the PADI Tech Deep manual that often you can be so negative that trying to maintain neutral buoyancy using a dry suit may exceed the capacity of the dry suit. Obviously, not a DIR diving is done with a dry suit anyway.

I guess that you might be able to use a lift bag or a SMB in the event of a wing failure, but I have not seen any evidence that this is part of DIR training?

What is the DIR contingency for wing failure and what is the feeling surrounding redundant bladders.

I have a pair of HP120's and a Dive Rite Super Wing (redundant). I believe that this wing has 77 lbs of lift.

I'll leave the discussion of the hazards of redundant bladder wings to others. Lets just look at the claim that you could not manage your buoyancy with your suit.

What configuration would leave you so negative that you cannot control your buoyancy with your drysuit?

If you start the dive negative by the weight of your back gas (+ maybe 2-3 lbs) even 2 x 130's full of air or nitrox should leave you only about 22-23 lbs negative if your wing failed completely.

23 lbs of lift requires .36 cuft of gas or cube about 8.5" per side, think water melon size. Your suit certainly has this much unused volume in it.

OTOH, if you are massively over weighted you might have a problem.

Tobin

 

[nadwidny]

Redundant bladders rank right up there with bungeed wings in the DIR world.

So is using PADI Tech as a reference.

DIR advocates diving a balanced rig which makes redundant bladders uneccessary. Discussions on what constitutes a "balanced rig" can probably be found with searches in this forum and also on the GUE website.

 

[b1gcountry]

Yeah, if you're diving HP120s, that is 240cf air or trimix. Air weighs 0.08lb/cf, and helium is lighter, so at the most you will be heavy by the weight of the air, or

240cf * 0.08lb/cf = 19.2lbs.

You are likely not going to have a catastrophic wing failure underwater, but since you are doing a pre-dive check, it will likely be later on in the dive, when you are less negative...but even if it blows when you stride in, you should be able to kick up/inflate your drysuit to account for 19lbs. In lifeguard class we had to retreive 10lbs from the bottom of the pool, and we weren't wearing fins.

Tom

 

[rjack321]

but even if it blows when you stride in, you should be able to kick up/inflate your drysuit to account for 19lbs. In lifeguard class we had to retreive 10lbs from the bottom of the pool, and we weren't wearing fins.

The corrugated hose popping off the elbow as you stride in is worst case. Correct, its not that big a deal to swim up if you are weighted properly.

A redundant bladder is a bunch of cra-p you don't need. I use a drysuit even in 79F water. For a dive of any substance you want to be able to control your own temp anyway.

 

[mikemikethepike]

I guess I coudl have answered by own quest by checking the GUE web site. There are several paragraphs on redundant bladders on their site.

It looks like the anwer to the failed wing is "swim it up." I am guessing that means dumping your rig when you reach the surface or hoping that you can make it back to shore/boat with your failed wing.

I like the idea of using the dry suit as the backup and I may be selling my super wing in favor or a classic wing.

 

[rjack321]

It looks like the anwer to the failed wing is "swim it up." I am guessing that means dumping your rig when you reach the surface or hoping that you can make it back to shore/boat with your failed wing.

No need to. Just keep the suit inflated. Stages if they are negative (rare) you can pass to a buddy. The boat comes to you.

 

[mikemikethepike]

Ok,

I have decided to sell my redundant wing and buy another a single wing with about 65 lbs of lift.

So, I have another question. Horseshoe wing or Donut Wing? I am leaning towards a dive rite classic 360.

 

[rjack321]

Ok,

I have decided to sell my redundant wing and buy another a single wing with about 65 lbs of lift.

So, I have another question. Horseshoe wing or Donut Wing? I am leaning towards a dive rite classic 360.

1) 65lbs is insane for a single tank. Try about 1/2 that, 30-35lbs. 40lbs is the absolute max needed and any bigger just flops around.
2) The dive rite classic 360 is a doubles ONLY wing that will taco like crazy on a single tank.

 

[Thalassamania]

The older I get the more I wish I had a redundant bladder, especially at night.