Twinset wing for single, is it really that bad ? (Comparison to big jacket bcd)

[iointerrupt]

What wing do you use with tiny doubles?

Apeks WTX-3. It's discontinued, but sometimes you can find them on eBay. It is by no means a great wing, but it fits good on tiny doubles.

 

[inquis]

Thank you for your answer, however 14 kilo would actually be too little lift even

Why is that?

 

[pdwh]

A new inflator is only 20 bucks at DGX.

Yeah, but I'm not sure about the safety/quality of the rest of the wing. Got it used and it sat in a garage for several years. I'm leaning toward trashing it and getting a new one. Just not worth the risk.

 

[Piotr_F]

Why is that?

Buoyancy calculation, at 60m depth I would be about 17 kg negatively buoyant with my current setup.

 

[inquis]

Buoyancy calculation, at 60m depth I would be about 17 kg negatively buoyant with my current setup.

Single-tank at 60m? Surely I've misunderstood something...

 

[Piotr_F]

Single-tank at 60m? Surely I've misunderstood something...

I'm French, here the "recreational" maximum depth is 60m on air and most of the people will do it on a single 15L steel tank.

 

[inquis]

I'm French, here the "recreational" maximum depth is 60m on air and most of the people will do it on a single 15L steel tank.

OK, so considering buoyancy alone... A 230bar/15L tank holds 4.5 kg of air when totally empty, and even a 300 bar cylinder tops out under 5.5 kg. This leaves ~12 kg of buoyancy that is lost to wetsuit compression, which seems implausible. Or are you in a drysuit and dealing with the possibility of a total suit failure with zero ditchable weight?

 

[sea_ledford]

The problem with using a doubles wing for a single tank isn't the amount of lift, it is the shape of the wing. If it is too wide, it can be VERY difficult to get all the air out, regardless of if you use the inflator hose or the bottom dump.

It sounds like you have some other equipment balance issues that need to be addressed to solve your problem, starting with why are you using a steel stage tank. Adding more lift is only one solution, and is rarely the best option.

 

[Piotr_F]

OK, so considering buoyancy alone... A 230bar/15L tank holds 4.5 kg of air when totally empty, and even a 300 bar cylinder tops out under 5.5 kg. This leaves ~12 kg of buoyancy that is lost to wetsuit compression, which seems implausible. Or are you're in a drysuit and dealing with the possibility of a total suit failure with zero ditchable weight?

I am mostly using the OptimalBuoyancy excel spread **** to do my buoyancy calculator, I'm sure it is not exact but I guess it give a good idea. So I end up with thos info for my global buoyancy :
Fixed weight (BCD/Wing, plate, regs, manifold, other fixed weight) : -8.6 kg
Weight of air carried using 1 stage tank : -5.7kg
Empty tank buoyancy : -1,4 kg
Personnal buoyancy : -2kg
Suit buoyancy (fresh water at 60 meter) : + 1.7kg

Ofc there is a lot of approximation but in the end that would get me at about 16kg negatively buoyant at 60m. According to this and accounting for any incident, I find 17L a bit too small, 20L wing would be good but they are relatively rare, 22L are only available for twinset.

 

[Piotr_F]

The problem with using a doubles wing for a single tank isn't the amount of lift, it is the shape of the wing. If it is too wide, it can be VERY difficult to get all the air out, regardless of if you use the inflator hose or the bottom dump.

It sounds like you have some other equipment balance issues that need to be addressed to solve your problem, starting with why are you using a steel stage tank. Adding more lift is only one solution, and is rarely the best option.

What do you call "equipment balance" ? About steel stage tank it's just an availability problem. I don't own one so I have to use steel ones even tho I agree with you on that.