BP&W question for doubles divers

[LowDrag]

My wife and I were talking over lunch today about doubles wings and why there are different lift capacities on the wing. We have seen wings with 55 lbs of lift and then we have seen wings with 100 lbs of lift. She was wondering why someone would use a 55 lb wing vs a 100 lb wing or vice versa. Not being a technical diver I did not have an answer for her but figured someone here could answer her question. Something that we were thinking about would be either the size of the tanks or the amount gear a diver needed to carry would probably be the determining factor on lift capacity. I was thinking things like stage bottles, redundant gear and so on.

Thanks in advance.

 

[Michael Guerrero]

You're thinking correctly. The amount of gear you carry determines your lift requirements (though there are wings built for wider tanks as well). The goal is to have enough lift for what you need, but not too much more as the wing will cause more drag since it's bigger. There are some people who think bigger is better though.

 

[tstormdiver]

Most 55# wings do well with most sets of doubles & maybe a stage or 2 (I've done 1 stage & a deco bottle). The larger wings are used for multiple stages, extra scooters,.. any equipment that can add considerably more weight.

 

[decompression]

The BCD is there to offset the amount of gas and keep you buoyant at the surface. That's why you'll see large wings on muti tank, multi stage dives. More commonly though, 40-50 lbs lift is more than sufficient for most doubles and a deco bottle. The goal is to keep the wing small and streamlined to reduce dynamic instability while still achieving your dive goals.


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[NAM001]

the smaller the wing the less unfilled bladder there is to allow the air bubble to travel from front to rear making maintaining trim diffiult. picture teh wing as a tube with a bubble of air in it. the air is 20% teh volumn of the large bladder head goes up and the bubble runs to your shoulders. loook down and it runs to our waist. Now picture a bladdetr that is 1/2 that size and the bubble like a loaf of bread is smaller in diameter and longer. When you look up and down teh bubble has less distance it can move, thus keeping the buble in a more constant position. the bubble moves 4" instead of 14".

 

[rongoodman]

The big 100# wings seem to be more popular in the UK for some reason, retraction bands and all.

 

[PfcAJ]

Most 55# wings do well with most sets of doubles & maybe a stage or 2 (I've done 1 stage & a deco bottle). The larger wings are used for multiple stages, extra scooters,.. any equipment that can add considerably more weight.

I've done dives with 4 stages, 3 deco bottles, and 2 scooters without need for a great big wing. 55-60lb works perfect.

Properly configured equipment does NOT add weight to you in the water.

You wing needs to be able to float your doubles (with your plate, regs, and accoutrements) without a diver in it. Anything bigger is without point. In reality that means a ~55lb wing for 8inch tanks (lp120s, hp130s, lp104s, etc) and a ~40lb wing for 7 inch tanks (al80s, lp85s, hp100s, etc). Oversized wings lead to gas trapping and increased drag while providing no benefit.

Bungees on wings have a whole host of potential problems that you can easily search for.

 

[LowDrag]

Thanks everyone. Great answers from everyone.

 

[karstdvr]

I've done dives with 4 stages, 3 deco bottles, and 2 scooters without need for a great big wing. 55-60lb works perfect.

.

Without a dry suit????

 

[PfcAJ]

Kelly I don't use my dry suit for lift. Like I said, properly configured gear (scooters, stages, deco bottles) doesn't add weight. The stuff is neutral or maybe a few lbs negative for the shallow deco bottles.