Is a large capacity wing more suited for cold water diving

[Tigerpaw]

I'm building a BPW specifically for cold water diving.

For water temps that are lower than 50 degrees, I dive with a 450g undergarment. It keeps me toasty but it's floaty to the point I need to have 25 pounds to submerge and that is with a HP100 tank (Single BM). I have set up a harness with a steel back plate that all together weighs 14 pounds and I'm currently looking for a wing to complete the setup.

I was looking at getting a wing that has 32 pounds of lift but then I came across another wing that has 45 pounds of lift that advertises as a cold water wing.

So based on the information provided is the larger wing better?

In the past I have dove with a 32lb wing with no problems but now I'm wondering if a larger capacity wing would be better. BUT I'm also thinking a larger wing would be harder to purge out all the air and could affect my buoyancy.

Am I over thinking this too much? My gut says stick with the 32lb wing. Looking for your thoughts and opinions. Thanks.

I'm 6' 240lbs

 

[Still Kicking]

Follow your gut -- 32lbs is plenty.

 

[MarkA]

Follow your gut -- 32lbs is plenty.

The size of your gut is not relevant in this situation (a little sarcastic)

The wing should do the following.
1. Compensate for the weight of gas
2. Compensate for loss of suit buoyancy

For me (in metric as i find it easier)
1. Weight of gas in 15l 232bar cylinder is approx 15x232x0.00125=4.35kg
2. Buoyancy of drysuit is 8kg (measured)
As a 32lb wing is approx. 32/2.2=14.5kg, this will support the 8+4.35=12.35kg
Your sums will be different

 

[rx7diver]

Also, your wing should be able to float your entire rig, including full cylinder, full pony cylinder, lights(s), etc., by itself on the surface.

A 45# wing seems to me to be much too large for a "normal" cold water single's rig (e.g., using a HP100 back cylinder and Luxfer LP30 pony bottle).

rx7diver

 

[Eric Sedletzky]

30-40 lb wing.
If you using smaller tanks use the 32
If you're using big tanks like a 120-130 use a 40.
A 30 can struggle keeping a big tank floating on surface depending on how heavy your plate is and if you have any extra weight on it. If you are one of those people that put all your ballast on your rig in an unditchable fashion then even a 40 might not be big enough with a big tank.

 

[MarkA]

Also, your wing should be able to float your entire rig, including full cylinder, full pony cylinder, lights(s), etc., by itself on the surface.

A 45# wing seems to me to be much too large for a "normal" cold water single's rig (e.g., using a HP100 back cylinder and Luxfer LP30 pony bottle).

rx7diver

Having seen a set of cylinders go to the bottom of the sea, I agree with you. It was while diving from an inflatable when horse collar BC's were used, so no inherent cylinder buoyancy when removing the cylinders in the water.

 

[DutchDiverDude]

Temperature should not affect this question.
Your wing volume should compensate for the weight of the air in the tank.
The rest of your gear should already be neutrally buoyant. Thicker undergarments means more lead, steel tanks, heavier gear etc, but all together should be neutral when your tanks are near-empty. If your rig is not balanced like this, you have another problem: then you are severely overweighted. (too much heavy stuff / lead). In that case, drop some lead, replace a steel backplate with aluminum, drop the heavy wreck reel for a lighter one, get a lighter battery, or do it the other way around: more undergarments).

Full tanks only add the weight of the gas, and that is what you are compensating for with your wing. Bigger tanks or more tanks = bigger wing.

A 45 pound wing is enough to carry all the gas in a set of manifolded doubles 12L doubles (<6kg / 13 Pounds), and 4 80 cuft stages (<3kg /6 Pounds each), with still some left to spare to compensate for drysuit leaks. You don't want to get this close to the maximum capacity, but you get the point.
Even in case of drysuit failures (i've seen a few), those typically allow a small stream of water in. I've seen people with malfunctioning zipper seals come out after an hour 'only' up to their knees full, after diving 45 min in a drysuit that was not properly zipped.

Don't get one that is too big either. The flaps on either side are more difficult to empty if not supported by a set of doubles. Else, your air in your wing will be well above your deflator in horizontal trim and won't easily come out.
There's good reason that 'singles' wings are much longer than they are wide, and 'doubles' wings are almost a perfect donut.

 

[Eric Sedletzky]

Temperature should not affect this question.
Your wing volume should compensate for the weight of the air in the tank.
The rest of your gear should already be neutrally buoyant. Thicker undergarments means more lead, steel tanks, heavier gear etc, but all together should be neutral when your tanks are near-empty. If your rig is not balanced like this, you have another problem: then you are severely overweighted. (too much heavy stuff / lead). In that case, drop some lead, replace a steel backplate with aluminum, drop the heavy wreck reel for a lighter one, get a lighter battery, or do it the other way around: more undergarments).

Full tanks only add the weight of the gas, and that is what you are compensating for with your wing. Bigger tanks or more tanks = bigger wing.

A 45 pound wing is enough to carry all the gas in a set of manifolded doubles 12L doubles (<6kg / 13 Pounds), and 4 80 cuft stages (<3kg /6 Pounds each), with still some left to spare to compensate for drysuit leaks. You don't want to get this close to the maximum capacity, but you get the point.
Even in case of drysuit failures (i've seen a few), those typically allow a small stream of water in. I've seen people with malfunctioning zipper seals come out after an hour 'only' up to their knees full, after diving 45 min in a drysuit that was not properly zipped.

Don't get one that is too big either. The flaps on either side are more difficult to empty if not supported by a set of doubles. Else, your air in your wing will be well above your deflator in horizontal trim and won't easily come out.
There's good reason that 'singles' wings are much longer than they are wide, and 'doubles' wings are almost a perfect donut.

The OP said "a HP100 tank (Single BM)".
Why are you talking about all your doubles, stage bottles, doubles donut wings, etc. I suppose there is a bit of bragging going on, yeah?
He will be using a single back mounted HP 100 cf tank

 

[grantmac]

A 40# wing is what I use for double 100s and a stage. It's overkill for a single.

 

[Brett Hatch]

I use a single wing for all of my single-tank diving: 32lb. Works well in a drysuit, thick wetsuit, thin wetsuit, or just a T-shirt and shorts

If you are one of those people that put all your ballast on your rig in an unditchable fashion then even a 40 might not be big enough with a big tank.

To Eric's point here, yes, if you are putting all of your ballast on your rig and you have a very heavy single tank, maybe 32lb is not sufficient. But I will say that putting that much ballast on the rig is not the easiest way to do it, at all. Your goddamn rig will weigh like 80 lbs! Much easier to put your lead on a belt, use a stainless backplate for some ballast, and maybe like 2-6 lbs lead into pouches on the rig to help you trim out, if needed. Safer for your back on shore, and safer in some (admittedly uncommon) situations in the water as well