Another Wing question

[Remy B.]

I tried to search but didn't have an answer I could understand ( because I don't know shait about it ), this is a random question but I'm sure someone have the answer

Which wing size is required for back double AL 100 + two AL 80, 5mm wetsuit, 82kg diver.

Thanks

 

[Jack Hammer]

Depends, its a function of your weighting. Which can vary considerably between divers. I've used a 45# wing for similar tank configuration and been fine. Best to try someone's gear and see what works for you.

I generally use stick with 2 wing sizes for doubles diving. One with 40-45# lift and one with 55-60# lift. The larger one gets used more for 8" tanks, the smaller size for 7.25" tanks. I dive mostly dry and temps vary from freezing (ice) to the 70*s.

I used a 35# wing once when diving doubled al80s in a 3mm suit with no stages and it was fine (no lead)

 

[Remy B.]

You are talking 2 tanks in your dives right ?

I'm talking about 4 tanks total, 2 AL 100 + 2 AL 80

 

[cool_hardware52]

I tried to search but didn't have an answer I could understand ( because I don't know shait about it ), this is a random question but I'm sure someone have the answer

Which wing size is required for back double AL 100 + two AL 80, 5mm wetsuit, 82kg diver.

Thanks

The answer lies in the buoyancy of your suit and the weight of your back gas.


Tobin

 

[Jack Hammer]

You are talking 2 tanks in your dives right ?

I'm talking about 4 tanks total, 2 AL 100 + 2 AL 80

I typically dive in a drysuit with steel doubles and stage/deco bottles using either a 45# or a 60# wing, as needed. The last example was for reference. As Tobin mentions and I alluded to, the amount of lift you need is a function of your gear (tanks, lights, BP, misc, spools, reels, etc) and your weighting. It can vary from diver to diver.

You need to determine your weighting to find what is ideal for you. This shouldn't be too difficult for someone who is diving doubles with stages/deco bottles. As a generalism, I would suspect something in the 40# range would work well to start with for what you describe and give you flexibility down the road.
I prefer to have a little more lift than i need to float on the surface more comfortably at the start of a dive. Over time youll likely end up with multiple wing sizes. I've come to prefer the donut styles as they are generally more streamlined.

 

[kensuf]

It depends on the diver (weight & body fat % -- a 250# weight lifter will sink compared to a 250# couch potato), density of the water (fresh/salt), and a few other things (backplate - al/ss?, lights?, etc).

Also keep in mind the AL100's tend to be floaty when empty.

But, I use a wing with supposedly 45# lift in freshwater and steel 104's (and a drysuit) and it works fine for me with a double stage (2x 80s).

Light Monkey

 

[tbone1004]

Ken, depends on Luxfer vs. Catalina, the Catalina's sink.... and Luxfers are still about 1.5lbs less floaty than standard 80's.

you are carrying 355cf of air, about 28.5lbs of gas, so you need at minimum 30lbs just to compensate for the gas. If you're diving in a drysuit or without a wetsuit, you could theoretically get away with a 35lb doubles wing *never seen a 30lb doubles wing*, and with the AL100's being 8" tanks you'll lose a bit of available lift.

To the OP. People try to complicate this whole thing, but it's really simple you need the following variables.

Total gas volume you'll be carrying, in this case nominal 30lb
Total ballast of the Rig. This is buoyancy of tanks+backplate+regulators blah blah blah *best way is to get a cheap luggage scale, put the whole rig in the water full and weigh it. Doesn't matter where the tanks are, just subtract the amount of gas from that total. In this case if all of the tanks are full, subtract 28.5 and you have your total rig buoyancy.
Total ballast of the diver. This is the buoyancy of you+buoyancy of your exposure protection. This is assumed to be 0+ballast if diving in a drysuit for wing calculations because you plan on worst case scenario which is a fully flooded suit. You get this number by inflating the suit to where you are comfortable and in normal diving conditions and using the total weight of the weight belt. Can be done in the shallow end of a pool.

If wet, it is the total amount of positive buoyancy at the surface, this assumes 100% compression at depth.

Sum everything up and that is your wing requirement. If you have a luggage scale, a weight belt, and access to a pool this is very easy and takes less than an hour.


Or, you just say to hell with it, and go get a 45lb wing and be fine with it. In a 5mm wetsuit you shouldn't need to wear that much lead even in the salty stuff. If you give us relevant information we can help better, your weight doesn't mean jack in this calculation. If you say "I wear x amount of lead when diving in this wetsuit and rig configuration* we can help you, if you wear 10lbs of lead wearing a single 80 then that is infinitely more useful information than how much you weigh.

 

[Remy B.]

I use 16lb with a 3mm wetsuit shorty with low sleeves and single AL80, my question comes because I see wings from 40 to 60lb lift and just didn't know if it had to do with the amount of bottles one can carry

 

[cool_hardware52]

I use 16lb with a 3mm wetsuit shorty with low sleeves and single AL80, my question comes because I see wings from 40 to 60lb lift and just didn't know if it had to do with the amount of bottles one can carry

With 16 lbs of lead and about 2 lbs of regulator you are carrying ~18 lbs of things that don't float, i.e. ballast.

A 3mm shorty will be maybe 3 lbs positive, and an empty al 80 will be +4 lbs.

A typical jacket BC is 3-5 lbs positive do to foam padding.

3mm Shorty +3
Al 80 +4
BC +4
Total +11

That suggests you are over weighted by ~18 -11 = 7 lbs.

I'd suggest a careful weight check.

Having said that keep in mind that any BC needs to do two things:
1) Float your rig at the surface if you ditch it
2) Be able to compensate for the maximum possible change in buoyancy of your exposure suit.

If you were to use a Stainless steel plate and harness and al 80 your rig would be about -10 lbs with a full tank, and your suit will still be + 3

Thin suits and buoyant tanks are why small wings are made.......

Tobin

 

[Redshift]

And adding to what others have said, I'd also say that it can depend on the environment you are diving in. A smaller wing can be ok in calm water, but in a bit more rough seas I prefer to have some extra lift on the surface.