Need Help - Dual Bladder BC, which ones and where to buy

[Zeke XA3]

I need to purchase a Dual Bladder BC for some tech and possible future cave courses.

I am looking towards OMS or Hacylon. From what ive seen on Zeagels in use they dont have my favor. I have also heard some good things about Hollis but not from Tech divers.

For these brands anyone got first hand experience of use. I am looking for as light as possible due to travelling, something that will fit my frame (tall and skinny) and where to purchase, UK or Oz!

Thanks guys.

 

[japan-diver]

Why a double bladder wing? Halcyon does not make a double bladder wing. For that Dive Rite makes a good version but the questions is why double bladder. You will have to match the wing to your tank size and weight - double eighty's about 40lb of lift- double 104 or about 55lbs or so of lift. I would suggest talking to your tech instructor to get recommendations.

 

[DevonDiver]

I'd recommend re-considering/re-researching your 'need' for a dual bladder wing. I'm not saying you shouldn't have one.... but you should assume that you need one either.

Halcyon don't make dual-bladder wings. Their kit is based on DIR methodology, which doesn't use dual bladders for emergency buoyancy contingency. Instead, they focus on proper balance of equipment and weighting.

 

[Zeke XA3]

Dual bladder - Based on personal reading, recommendation from both my preferred Cave Instructor and TDI Instructor and listed as required by the place i want to do my TDI courses at.

Why is there so much negative to dual bladders? I understand that it is an extra hose and extra thing to think about, using the right inflator etc but surely if used and it becomes second nature like most equipment you are comfortable with using the face you have the independent backup is a worthwhile investment. Again this is kit that i am looking to use for a possible full cave course and other technical types of diving.

 

[Sas]

Why is there so much negative to dual bladders? I understand that it is an extra hose and extra thing to think about, using the right inflator etc but surely if used and it becomes second nature like most equipment you are comfortable with using the face you have the independent backup is a worthwhile investment. Again this is kit that i am looking to use for a possible full cave course and other technical types of diving.

Ok the problems people have with it is that it adds extra failure points to the kit if you have them both attached (inflator hoses do fail and can do things like auto inflate, this is relatively common, and it might be hard to tell which one is autoinflating), also a lot of people dive with the unused one not attached and it can be a PITA to attach if you need it urgently (this was my experience with it for sure when testing one out) and damage to wing can damage both bladders. Those are the main reasons, and I do not consider them trivial so I got a single bladder wing and use my drysuit as backup.

What reasons were you given for requiring one on your TDI course? And also your cave training (which agency, btw? my cave instructor was not a fan).

All that being said, OMS has double bladder wings and I have been happy with my OMS wings (though they are single bladder), not sure what others are out there.

 

[Zeke XA3]

Cave - IANTD,
TDI - Instructor has just specified that he requires dual bladder BCs to be used. I am writing a long email asking about all his requirements but getting extra info by coming here too

What equipment were you using for auto inflate to be a problem? What sort of incident rate are you talking about? Personally auto inflate for me is 1 on 2-3000 dives. I would prob dive with it attached. Im planning on doing some of the diving in warmer water so doubt it will be drysuit so i dont have the redundant buoyancy option there.

 

[Sas]

What equipment were you using for auto inflate to be a problem? What sort of incident rate are you talking about? Personally auto inflate for me is 1 on 2-3000 dives. I would prob dive with it attached. Im planning on doing some of the diving in warmer water so doubt it will be drysuit so i dont have the redundant buoyancy option there.

Seen it happen to various BCs about half a dozen times. Had it happen a few times with my (OMS) BC in almost 500 dives, from sand in the inflator (I do a lot of shore diving).

Sure, to each their own with what people prefer as redundant buoyancy, I was just listing the reasons why I didn't choose a dual bladder wing. Some people use AL doubles when diving doubles with wetsuit too and dive with a single bladder. Look up 'balanced rig' for more info, like this article: Weighting: In Search of a Balanced Rig.. - DIR Explorers

Another option for redundant buoyancy is a lift bag, though I don't think much of that personally, as if you lose control of your buoyancy, it seems a pain to faff around inflating a lift bag, though never tried this myself.

 

[knowone]

Note to self

No OMS style inflator fore shore diving with particulates.

Faffing around with an smb as redundant lift is faff for sure.

If one understands that it is not there until needed
well then that is all that is needed to be understood.

 

[DevonDiver]

Why is there so much negative to dual bladders?

I think I could summarize the issues:

1) There are other alternatives; i.e. 'Balanced Rig' approach and DSMB/Bag.
2) Another hose, another failure point.
3) Any tiny leak of gas into the redundant bladder at tech depth can lead to runaway buoyancy as it expands on ascent. Big risk when you have substantial deco obligation.

 

[Zeke XA3]

SAS - Thanks for the link will read in detail tonight. Ive been told i need to practice using a lift bag as a redundant buoyancy backup so i suppose that is an option but i doubt i could use that in an overhead environment?

Knowone - I think i understand what you are saying! But i doubt ill be doing much shore diving and smb would be last resort i suppose !

DD - I understand the concept behind a balance rig but surely a balance rig should go with a redundant buoyancy option? And using a lift bag has its own problems as well of course and again may not be useful in an overhead environment? As for failure point, is this a real risk or are we talking a one in few ten thousand chance? As with any piece of equipment using it entails a risk of failure including Lift bags etc. Yes by not using something you eliminate the risk but then your increasing the risk that you were initially preventing...if you follow my drift? As for your third point, one i had not considered, would there be a way to check this during pre dive? If it happened though pretty easy to deal with since i would assume training covers switching between bladders to check you can use both right and left hand etc?

Please dont take these questions as me taking a side in this but since everyone here is on one side i need to try and get a balanced view by asking all these!