wing lift question.

[din]

I did a rudimentary search and gave up when I didn't find what I was looking for, because it's snowing today, and that's increased my usual laziness quite a bit.

as I'm piecing my gear together, I'm almost at the point of selecting a BP/W. I'm not going to be able to afford anything super fancy, and I'm going to be using one rig for both SW and FW, warm and cold(ish). since I'm still getting the feel of things, I'm only going to be diving singles for a while. right now I'm looking at the oxy travel plate with a mach v wing, but I'm not sure how much lift to get for an all-rounder. I weigh in the neighborhood of 220-230; would it be better to get the 40# or would that just be overkill? the last time I dove in a jacket BC and 7mm suit with a 5mm hooded vest, and needed about 40# to sink.

[BouzoukiJoe A.K.A. wrecker130 AKA Chuck Norris AKA joeforbroke (banned)]

40# seems like a lot of weight. Are you sure you need that much?

A wing needs to be able to float you and your gear if your suit loses buoyancy which is an issue with a drysuit or wet suits when diving very deep.

30# is generally good enough for any singles rig.

However, the wing also needs to be able to float the rig at the surface when you are not wearing it. If you put all 40# on the rig, you may need 40# plus. If you split the weight between the rig and the weight belt, 30# should be enough.

[Straegen]

The conventional thinking is that a wing should offset your exposure suit and be able to float itself at any point during the dive.

If you use an exposure suit that is say 7mm neoprene and it looses all its buoyancy at depth, your wing needs to be able to bring that to the surface. In most instances a 30lb wing is more than enough to get the job done and then some. I would add that you might want a little extra to pop your head above the water, but usually a 30lb has more than enough to do just that.

Your weight is really not relevant for wing selection since you weigh pretty much the same throughout the dive. So if it takes 10lbs to sink you at the start of the dive it takes the same 10lbs at the end so your wing doesn't have to do any work. I follow the school that in a near perfect world your BP negative buoyancy offsets your natural positive buoyancy and the buoyancy of your wetsuit should be compensated for via a weight belt. Air consumption buoyancy can be compensated in the weight belt or the BPW but I prefer the BPW. That is opinion though.

I just ditto'd the last post more of less... beat me to it.

[MSilvia]

Go with the 30.

[gedmondson]

Nope, go with the 40... Better to have more than enough lift than not enough.

[Gombessa]

Originally Posted by gedmondson

Nope, go with the 40... Better to have more than enough lift than not enough.

It's better to accurately determine the lift you need, and then get the smallest wing that satisfies that requirement, than to simply overshoot by getting a wing with excessive lift.

40lb is quite a bit of ballast if you're talking about having that all on a belt. Seeing how you're new, it's likely that your weighting requirements will drop as you gain a little more comfort and experience in the water. However, there's no doubt that in cold water you may very well need a lot of lead to sink.

Before you decide on a wing, what you should do is get in chest-high water with all of your exposure protection on (suit, gloves, boots, hood, etc.) with a big bag of weights. Lift your legs to try to float, and remove weights until you're just neutral at eye level in the water while holding the bag. The weight remaining in the bag is how much total weight you need, including your gear. FYI, for most people in a 7mm suit, that's around 25-30lb.

Assuming your exposure suit loses 90% of its buoyancy at depth (you'd need to go pretty deep for that), you're going to want a wing that gives you ~25-27lb of lift to stay neutral (and as an aside, in case of a wing failure at depth, you'll want to make sure that about 16lb is ditchable so you can swim the rig up).

On the surface, your wetsuit + proper weighting will make you neutral, and anything your wing provides will make you positive.

For a single bp/w solution, I generally like going with a full SS plate. It's about 5-6lb, and 8-9lb more negative than a typical BCD. With a weighted STA (another 6lb), that provides you with 12lb of well-positioned ballast which you don't need to wear on your body. So in the above example, if you need 30lb to offset your exposure protection, that leaves you with 18lb to allocate with your belt, other ditchable items, tank, etc.

As a bonus, some people find that using a SS plate + STA allows them to dive fully balanced in warm water without needing any ditchable weight at all. A 30# wing is a bit overkill in the tropics, but if it's all you have, it's pretty streamlined to begin with and will serve the job well. I use this setup and have found that it works equally well in both cold and warm water.

The takeaway here is really that you will be most happy if you do a proper weighting check and get a wing that is matched to your needs, rather than make a wild guess and grossly pad for "safety" with a wing that's unnecessarily large.

[Splitlip]

I would lean toweards the 30. The Oxy 40 though, if it gives you a little more peace of mind, fine. The MV's are designed so nicely, you won't really experience any of the bad side effects by over sizing a wing.

I would not bother with the "travel plate" . Just go with an aluminum plate for similar buoyancy traits and more options/comfort.

[gedmondson]

There is no downside to too much wing. Too little...
The compulsives will tell you you need to use a spreadsheet to figure your lift. Just get a 40 for single, 60 for double and go diving.

[CompuDude]

Originally Posted by gedmondson

There is no downside to too much wing. Too little...
The compulsives will tell you you need to use a spreadsheet to figure your lift. Just get a 40 for single, 60 for double and go diving.

There is MORE downside to too little wing than too much. But if you really think there is NO downside to too much wing... you're either misinformed, or lying to yourself.

[Rainer]

Clearly you have no idea what you're talking about.

In any case, the best thing someone can do who is considering a new BC is actually go out and determine their actual lift requirements (can be done in a pool with some lead and the rest of the gear you plan to use).

Originally Posted by gedmondson

There is no downside to too much wing. Too little...
The compulsives will tell you you need to use a spreadsheet to figure your lift. Just get a 40 for single, 60 for double and go diving.