DevonDiver
N/A
To the OP; what purpose would you intend to use the wing for?
The majority of divers who utilise wings for technical, deep or overhead (wreck/cave) environment diving follow the concept of 'minimalism' to a greater or lesser degree. This concept focuses on identifying what you actually need and removing surplus. The underlying motivation behind this is that complexity adds task-loading and more functions/items equals more risks of failure.
This concept certainly applies to wings...
Dual bladder wings offer the benefit of redundant buoyancy control. That seems like a good feature to have, but there are drawbacks that you need to be aware of. Firstly, you will be doubling your risk of LPI free-flow and unintended wing inflation. Even a small 'trickle' leak into that bladder can cause major problems when you start to ascend. For deep/technical diving, this is a serious situation that could get you bent, worse. Having a redundant bladder, even if it isn't used during a dive, requires more task loading, skills and procedures for safe use. You need to identify a reliable strategy for preventing the risk of accidental inflation. You need to identify a strategy/procedure for swapping buoyancy from one bladder to the other. You need to consider adding checks/procedures on every dive to continually ensure the redundant wing is empty.
Over-sized bladders have drawbacks also. Firstly, it is a bigger air-space. In the event of unintended inflation (LPI freeflow etc), then the bladder will have a huge amount of lift. Secondly, all that extra bladder/material will have an impact on how the wing feels underwater. Many divers feel uncomfortable because those wings can 'taco' or because the air can get trapped into pockets within the wing (causing stabilization problems), or making the wing harder to vent. Because of the extra volume, the wing uses bungees to restrict it. There are serious debates about the drawbacks to bungeed wings; mainly revolving around the potential issue that the elasticity of the bungees would forceably vent the wing if it were punctured.
I do have issues with the mindset of "just in case you needed it". Technical and overhead diving requires a much more scientific and methodical approach to equipment configuration. Adding equipment, features and functions to your rig 'just in case' implies that insufficient consideration has gone into the design and calculation of a rig.
There is no requirement for redundant bladders, if you have formulated your rig to be 'balanced'. Google 'Balanced Rig'. This is a methodical approach to creating a configuration that is both safe and minimalist. I won't deny that it requires more brainwork and more flexibility, but it is respected and offers many debatable safety benefits.
There is no requirement for over-sized bladders. You need what you need. Your needs can be easily calculated. Unless you foresee a future requirement to dive with multiple extra-high capacity steel cylinders, and other heavy equipment (tools etc) then you are never going to need a super-high volume wing. Take the time to work out your buoyancy requirements. Opting for a giant 'catch-all' wing is just an excuse to skimp on proper configuration calculations. It will bring no benefits, but there will be debatable drawbacks. That is the price of opting for the lazy, convenience solution...
Redundant, over-sized wings also add a lot of bulk and weight, which is an issue if you want to travel with the kit. It's harder to pack and it takes up more of your airline baggage allowance. You also have more things to go wrong... at least from a servicing point of view, that means more hoses to replace, bladders to replace, LPIs to replace.... and thus, more costs to run over the long-term.
My personal perspective - I have used both single and double bladder wings. These have included OMS, Halcyon, Custom Divers and other brands. I currently own 2 doubles wings; a 40lb Halcyon Evolve and a 66lb Custom Divers TDB.
The Custom Divers TDB was my first doubles wing. I bought it because I was diving steel 15L doubles, steel backplate, with a steel stage and heavy umbilical torch. It was a very negative rig and little consideration had gone into its design and balance. Even then, 66lbs of buoyancy was easily sufficient to float it. The TDB has a redundant bladder. This seemed like a good idea for me at the time (I bought the wing prior to taking tech training), as it seemed 'safer'. Only when I later went through tech training did I start to see lots of drawbacks. I opted to leave the redundant bladder disconnected from the LPI for safety reasons. This meant I had to drill and drill a response to connect it quickly in an emergency. I had to add procedures to check that the bladder was empty prior to ascent. This made my ascent/deco on tech dives more complicated than necessary. The wing is also bulky...and takes up a lot of space and weight in my dive bag. I only still use the TDB because it allows the use of independant doubles via cam band... which makes it perfect for travelling. I can get on any recreational dive boat and simply slot in 2 AL80's. If it wasn't for that, then the wing would have been Ebay'd long ago.
When I look back at my early equipment choices, I see that they were driven by ignorance and convenience. They resulted in wasted money and the need to refine/replace equipment later on, when I had learned superior and simpler solutions to the issues of redundancy and buoyancy.
I now use the Halcyon Evolve for most of my doubles diving. The 40lb wing is easily sufficient for diving aluminium cylinders/stages. I carry little surplus weight and can easily swim the equipment up in the event of bladder failure. It is brutally simple, and this reduces my task loading making dives more enjoyable and giving me more capacity to deal with increasingly-demanding dive goals. My equipment configuration benefits from a 'complete approach', where every item has been selected to form a total integrated system.
It seems to me that your proposed solutions are being forced upon you. You start with steel cylinders, which then forces you to add buoyancy. The risk of bladder failure then forces you to consider a redundant bladder. The redundant bladder forces you to add a hose to your reg. The redundant bladder also forces you to add extra procedures and checks to your dives. One item selection causes knock-on issues, which then dictates solutions. Those solutions cause further knock-on issues. So on and so on.....
My advice is to stop right now. Stop and think. Go back to the very basics... identify what you want to achieve. Plan an ideal rig based on those needs. Be prepared to exchange/replace items (i.e. cylinders) that will prevent you from achieving that ideal rig. Don't let yourself get forced into an equipment configuration caused by the knock-on demands of one or two initial equipment choices. It's better to sell/replace/exchange a few components now, rather than get drawn into purchasing more and more kit that is less than ideal - just to compensate for your initial non-ideal kit. It will save you a lot of money in the long-run, trust me.
The majority of divers who utilise wings for technical, deep or overhead (wreck/cave) environment diving follow the concept of 'minimalism' to a greater or lesser degree. This concept focuses on identifying what you actually need and removing surplus. The underlying motivation behind this is that complexity adds task-loading and more functions/items equals more risks of failure.
This concept certainly applies to wings...
Dual bladder wings offer the benefit of redundant buoyancy control. That seems like a good feature to have, but there are drawbacks that you need to be aware of. Firstly, you will be doubling your risk of LPI free-flow and unintended wing inflation. Even a small 'trickle' leak into that bladder can cause major problems when you start to ascend. For deep/technical diving, this is a serious situation that could get you bent, worse. Having a redundant bladder, even if it isn't used during a dive, requires more task loading, skills and procedures for safe use. You need to identify a reliable strategy for preventing the risk of accidental inflation. You need to identify a strategy/procedure for swapping buoyancy from one bladder to the other. You need to consider adding checks/procedures on every dive to continually ensure the redundant wing is empty.
Over-sized bladders have drawbacks also. Firstly, it is a bigger air-space. In the event of unintended inflation (LPI freeflow etc), then the bladder will have a huge amount of lift. Secondly, all that extra bladder/material will have an impact on how the wing feels underwater. Many divers feel uncomfortable because those wings can 'taco' or because the air can get trapped into pockets within the wing (causing stabilization problems), or making the wing harder to vent. Because of the extra volume, the wing uses bungees to restrict it. There are serious debates about the drawbacks to bungeed wings; mainly revolving around the potential issue that the elasticity of the bungees would forceably vent the wing if it were punctured.
I do have issues with the mindset of "just in case you needed it". Technical and overhead diving requires a much more scientific and methodical approach to equipment configuration. Adding equipment, features and functions to your rig 'just in case' implies that insufficient consideration has gone into the design and calculation of a rig.
There is no requirement for redundant bladders, if you have formulated your rig to be 'balanced'. Google 'Balanced Rig'. This is a methodical approach to creating a configuration that is both safe and minimalist. I won't deny that it requires more brainwork and more flexibility, but it is respected and offers many debatable safety benefits.
There is no requirement for over-sized bladders. You need what you need. Your needs can be easily calculated. Unless you foresee a future requirement to dive with multiple extra-high capacity steel cylinders, and other heavy equipment (tools etc) then you are never going to need a super-high volume wing. Take the time to work out your buoyancy requirements. Opting for a giant 'catch-all' wing is just an excuse to skimp on proper configuration calculations. It will bring no benefits, but there will be debatable drawbacks. That is the price of opting for the lazy, convenience solution...
Redundant, over-sized wings also add a lot of bulk and weight, which is an issue if you want to travel with the kit. It's harder to pack and it takes up more of your airline baggage allowance. You also have more things to go wrong... at least from a servicing point of view, that means more hoses to replace, bladders to replace, LPIs to replace.... and thus, more costs to run over the long-term.
My personal perspective - I have used both single and double bladder wings. These have included OMS, Halcyon, Custom Divers and other brands. I currently own 2 doubles wings; a 40lb Halcyon Evolve and a 66lb Custom Divers TDB.
The Custom Divers TDB was my first doubles wing. I bought it because I was diving steel 15L doubles, steel backplate, with a steel stage and heavy umbilical torch. It was a very negative rig and little consideration had gone into its design and balance. Even then, 66lbs of buoyancy was easily sufficient to float it. The TDB has a redundant bladder. This seemed like a good idea for me at the time (I bought the wing prior to taking tech training), as it seemed 'safer'. Only when I later went through tech training did I start to see lots of drawbacks. I opted to leave the redundant bladder disconnected from the LPI for safety reasons. This meant I had to drill and drill a response to connect it quickly in an emergency. I had to add procedures to check that the bladder was empty prior to ascent. This made my ascent/deco on tech dives more complicated than necessary. The wing is also bulky...and takes up a lot of space and weight in my dive bag. I only still use the TDB because it allows the use of independant doubles via cam band... which makes it perfect for travelling. I can get on any recreational dive boat and simply slot in 2 AL80's. If it wasn't for that, then the wing would have been Ebay'd long ago.
When I look back at my early equipment choices, I see that they were driven by ignorance and convenience. They resulted in wasted money and the need to refine/replace equipment later on, when I had learned superior and simpler solutions to the issues of redundancy and buoyancy.
I now use the Halcyon Evolve for most of my doubles diving. The 40lb wing is easily sufficient for diving aluminium cylinders/stages. I carry little surplus weight and can easily swim the equipment up in the event of bladder failure. It is brutally simple, and this reduces my task loading making dives more enjoyable and giving me more capacity to deal with increasingly-demanding dive goals. My equipment configuration benefits from a 'complete approach', where every item has been selected to form a total integrated system.
It seems to me that your proposed solutions are being forced upon you. You start with steel cylinders, which then forces you to add buoyancy. The risk of bladder failure then forces you to consider a redundant bladder. The redundant bladder forces you to add a hose to your reg. The redundant bladder also forces you to add extra procedures and checks to your dives. One item selection causes knock-on issues, which then dictates solutions. Those solutions cause further knock-on issues. So on and so on.....
My advice is to stop right now. Stop and think. Go back to the very basics... identify what you want to achieve. Plan an ideal rig based on those needs. Be prepared to exchange/replace items (i.e. cylinders) that will prevent you from achieving that ideal rig. Don't let yourself get forced into an equipment configuration caused by the knock-on demands of one or two initial equipment choices. It's better to sell/replace/exchange a few components now, rather than get drawn into purchasing more and more kit that is less than ideal - just to compensate for your initial non-ideal kit. It will save you a lot of money in the long-run, trust me.
