Wing size

[stuartv]

40 lbs (18kg) is all you need for steel 12 litre doubles. These contain about 5kg of gas weight from full to empty. An ali80 contains about 1kg to minus one kg from full to empty — they float when empty.

So 6kg/14 lbs is all you’re compensating for. The rest is floating on the surface.

If diving in a wetsuit there might be a kg or two difference between shallow and deep.

This is why 40 lbs / 18kg is all you need.

Double 100s hold about 16# (7.3kg) of gas. An AL80 is about 6# (2.7kg) of gas. So, more like 10kg, total. Not 6.

So, if you are perfectly weighted, you would be 22# negative, with an empty wing and full tanks.

How much lead are you carrying? (and are you really perfectly weighted?) If your drysuit totally floods, will 40# be enough to get you and all your stuff to the surface without any help from the drysuit? Probably, but do the math.

Personally, I would suggest to the OP to just get a 60# wing and be done buying wings. There is really not a downside to a 60 versus a 40. The difference in streamlining is really negligible (assuming well-designed wings). I've tried half a dozen or so different doubles wings. My favorite is the Dive Rite Classic XT (a 60# wing). It affords me good horizontal trim with no faffing around. Unlike some other name brand wings that made me need a tail weight in order to get good trim.

 

[stuartv]

And if the 40 is enough to get you and your flooded drysuit to the surface, is it enough to let you stay there with your head comfortably out of the water? Getting your head up out of the water requires another, what? 10 # of lift?

 

[Rilelen]

Personally, I would suggest to the OP to just get a 60# wing and be done buying wings. There is really not a downside to a 60 versus a 40. The difference in streamlining is really negligible (assuming well-designed wings). I've tried half a dozen or so different doubles wings. My favorite is the Dive Rite Classic XT (a 60# wing). It affords me good horizontal trim with no faffing around. Unlike some other name brand wings that made me need a tail weight in order to get good trim.

I also dive the DiveRite Classic XT, mostly with HP100s and LP85s; I know folks have talked about streamlining/tacoing issues when diving a 60# wing with smaller-diameter tanks, but I've genuinely never had any issues (and I can also use the same wing with LP104s, which is very convenient).

 

[johnydive]

And if the 40 is enough to get you and your flooded drysuit to the surface, is it enough to let you stay there with your head comfortably out of the water? Getting your head up out of the water requires another, what? 10 # of lift?

With the dry add about 22lbs of led! For single al!

 

[stuartv]

With the dry add about 22lbs of led!

That is a LOT of lead when you are diving double steels. Even in a drysuit. When I dive double steels in salt water and drysuit, I might have 4 - 8# of lead. But, you might be wearing a much more floaty suit and undies than I do, so I'm not saying it's wrong. It could be. Or it could be exactly what you need.

But, if you are diving with double steels and 22# of lead, then I would definitely NOT go with a 40# wing.

A 60 is kind of a one-and-done purchase. My first tech instructor told me to save myself multiple purchases and get a 60 to start. I listened to the experts here on SB and bought a 45. I still have it and still use it (mainly when I'm letting someone else use my 60). But, it wasn't long after that I bought a 60. I could have saved myself several purchases if I had just bought the 60 first.

 

[Jim Lapenta]

If diving double steels larger than LP72s, I would choose a 50-60 lb wing and be done with it. You are sure to have enough lift for any gear failure you may have and more importantly, enough to assist another diver should they require it.
The latter is always something I took into account after having to bring a diver to the surface in a simulated rescue and keep them afloat. I was in LP 85's and they were using LP95s. Both of us in drysuits and carrying stages. I was very glad I had that 58lb wing.

 

[johnydive]

That is a LOT of lead when you are diving double steels. Even in a drysuit. When I dive double steels in salt water and drysuit, I might have 4 - 8# of lead. But, you might be wearing a much more floaty suit and undies than I do, so I'm not saying it's wrong. It could be. Or it could be exactly what you need.

But, if you are diving with double steels and 22# of lead, then I would definitely NOT go with a 40# wing.

A 60 is kind of a one-and-done purchase. My first tech instructor told me to save myself multiple purchases and get a 60 to start. I listened to the experts here on SB and bought a 45. I still have it and still use it (mainly when I'm letting someone else use my 60). But, it wasn't long after that I bought a 60. I could have saved myself several purchases if I had just bought the 60 first.

I never dive my double yet…. I thought we were talking in general with a foamy undergarment and al80 I’m about 20-22lbs!

 

[buddhasummer]

There's two 60 OMS and H monster wings at the top

View attachment 817507

You have more gear than most shops I've been too

 

[stuartv]

I never dive my double yet…. I thought we were talking in general with a foamy undergarment and al80 I’m about 20-22lbs!

Ah. That sounds much more reasonable. In fresh water, with a steel back plate, you might not need any weight with double steel 100s. Just have to try it and see.

 

[RyanT]

is it enough to let you stay there with your head comfortably out of the water?

And this is especially true if the seas get big. There was a dive I made once where I surfaced the seas were running 7-10'. I was diving a set of LP 85 doubles. My 60# wing was unable to provide enough lift to keep my head above the biggest rollers. I'm sure glad I had the 60lb and not my 45lb wing.