Wings suitable for both double-7s and double-12s

[evil_xander]

- Balance - double-7s spread the weight out more evenly - a single 15 is pretty unstable.

Nothing to do with DIR, but how come?

I dive with a single 15 on a singles wing and it's as stable as it can be, no STA required, doesn't move anywhere, and no problems in water.

 

[BarryNL]

Nothing to do with DIR, but how come?

I dive with a single 15 on a singles wing and it's as stable as it can be, no STA required, doesn't move anywhere, and no problems in water.

Well, it's not so bad that I have problems with it. It's just that doubles feel so much more balanced in the water than a big steel single.

Admittedly, losing the STA to get the centre of gravity closer to me might help.

 

[JeffG]

Erm, I understand that you certainly never use your stages as part of your weighting and need to be able to hold a 5m stop without them but they do impact required wing lift. You need sufficient lift to be able to float you at the surface with full doubles and with full stages, which is more lift than you need for the doubles alone.

If you are using proper stages/deco tanks, the lift required is minimal.

4 lbs max for an 80 (thats if you were using it for 50% or 100%)
maybe 2 lbs or so for a 40.

So for a 150ft dive with a 40 of 50%, my wing will need to "lift" 2 lbs of deco tanks. Wow...2 lbs.

 

[cool_hardware52]

Erm, I understand that you certainly never use your stages as part of your weighting and need to be able to hold a 5m stop without them but they do impact required wing lift. You need sufficient lift to be able to float you at the surface with full doubles and with full stages, which is more lift than you need for the doubles alone.

No. Your stages should not impact the required size of the wing.

Lets assume your exposure suit is 24 lbs positive, and you are using D12's. You have about 16 lbs of back gas. That means you will need a wing of least 24 + 16 + ~3 = 43 lbs.

To stay at the surface at the start of the dive, assuming you are ~19 lbs negative (16 + 3) you will have used 19 of the 43 lbs of lift your wing can provide. That leaves 24 more. If you add an al 80 (-4 rigged) you need to use 4 of the remaining 24 lbs of lift you have available.

How exactly does this require a larger wing?

Tobin

 

[limeyx]

No. Your stages should not impact the required size of the wing.

Lets assume your exposure suit is 24 lbs positive, and you are using D12's. You have about 16 lbs of back gas. That means you will need a wing of least 24 + 16 + ~3 = 43 lbs.

To stay at the surface at the start of the dive, assuming you are ~19 lbs negative (16 + 3) you will have used 19 of the 43 lbs of lift your wing can provide. That leaves 24 more. If you add an al 80 (-4 rigged) you need to use 4 of the remaining 24 lbs of lift you have available.

How exactly does this require a larger wing?

Tobin

I'm a touch confused here about why the wing needs to compensate for the 24 pounds -- maybe I am not getting something. Are you assuming a wetsuit?

With a drysuit (assuming non-compressible), then I dont think the wing needs that much, right ?

Maybe I will try my double 12's and add stages and see the results

So far I have determined:

40 pound wing, double 130's, 2 Al40's -- not a good idea unless you can drink seawater
40 pound wing, double 130's, 1 AL40, 1AL80 + video camera -- same

But in these cases, I dont think it was as much the buoyancy of the wing, more that I just sat low in the water. The 55 pounder seems to have me a bit higher out of the water, which is definitely more comfortable.

 

[BarryNL]

No. Your stages should not impact the required size of the wing.

Lets assume your exposure suit is 24 lbs positive, and you are using D12's. You have about 16 lbs of back gas. That means you will need a wing of least 24 + 16 + ~3 = 43 lbs.

To stay at the surface at the start of the dive, assuming you are ~19 lbs negative (16 + 3) you will have used 19 of the 43 lbs of lift your wing can provide. That leaves 24 more. If you add an al 80 (-4 rigged) you need to use 4 of the remaining 24 lbs of lift you have available.

How exactly does this require a larger wing?

Tobin

Well, if you already have a 43 lbs wing, it doesn't. If you only have a 22 lbs wing then you have enough for just your doubles but not your stages.

Actually, you need at least 10 lbs to comfortably float your head out of the water, so given your figures a 30 lbs wing would be sufficient for diving the doubles, but not for diving the doubles plus stages.

 

[JeffG]

Well, if you already have a 43 lbs wing, it doesn't. If you only have a 22 lbs wing then you have enough for just your doubles but not your stages.

Actually, you need at least 10 lbs to comfortably float your head out of the water, so given your figures a 30 lbs wing would be sufficient for diving the doubles, but not for diving the doubles plus stages.

I've never seen a doubles wing that small. (22 lb or 30 lb. That sounds like a singles wing)

 

[*Floater*]

AL80's are about 11 liters, so 12L tanks are about the same. In a 3mm wetsuit I used the Evolve 40 to dive AL80's usually with 1 AL40 deco bottle, but sometimes also another AL80 for reserve gas and it was enough lift. Granted I didn't have to worry about drysuit floods and wetsuit compression was minimal, but still I would use a 40# wing with 12L tanks. In fact I did one or two deco dives with 12L steel doubles and an AL40 deco bottle and it was fine even though I was overweighted because I only had a steel plate at the time which was too heavy with steel tanks. I would rather plan on using an SMB or liftbag to deal with a complete drysuit flood during OW diving than dive an oversized wing just for that contingency. But then again some people just need a little extra lift. (But I'm not sure whether or not my approach is DIR).

 

[cool_hardware52]

Well, if you already have a 43 lbs wing, it doesn't. If you only have a 22 lbs wing then you have enough for just your doubles but not your stages.

Barry,

There are very specific reasons why I suggested a 43 lbs wing as a minimum. I've detailed these for you twice already; You need to be able to offset both the potential loss of buoyancy from a total suit failure, and be able to stay at the surface when negative by the weight of your back gas + 2-3 lbs.

If you want to ignore these basic requirements and raise arguments based on wing sizes that are just simply unsafe and insufficient, (22 lbs doubles wing for example) then I have to ask why you posted your original question.

If you are already certain you have all the answers why bother asking? I wish both you and your fundies instructor the best of luck.

Tobin

 

[JeffG]

If you want to ignore these basic requirements and raise arguments based on wing sizes that are just simply unsafe and insufficient, (22 lbs doubles wing for example) then I have to ask why you posted your original question.

Just him trolling I suspect.

Maybe he will be one of the first ones gone when they put the new DIR forum rules in.