size of wing

[fjpatrum]

I am familiar with the wing lift calculator posted as a sticky here but I have a couple of questions for folks.

I use a light weight wing (~18-20 pound lift) and it has served me well with an AL80. I tried a 30# HOG wing and didn't like it... too sloppy and floppy for my taste. I, however, just bought some HP100 tanks. This will mean that when I'm diving warm water, I'm negative. Even moving to my PVC backplate vice my steel plate, I'm on the edge of being negative with no extra lead. (In warm water I dive with 2-4 pounds now in a 5mm suit).

So, what's the largest tank you've used with a small "travel" wing? The lift calculator says I'm good as long as I don't have integrated weights, which I don't but I'm wondering if anyone has any experience with making this transition (-8 pounds full and -5 pounds at 500 psi) using a small wing. What are your thoughts on your own comfort?

I'm not likely to go to anything bigger than a 24# wing (if I can find or make one) but I'm hoping to stay with my current one.

 

[fnfalman]

What brand and model of the HP100 tank? These tanks have specific and individual buoyancy characteristics.

 

[fjpatrum]

I think they're Sherwoods. They're stamped 3500 and had Sherwood valves on (though that doesn't necessarily mean anything) and the guy I bought it from thought they were Sherwood as well.

When we're talking about generalizations, though, the specifics don't really mean that much. It's more a matter of "did you find a big issue switching from AL80s to much heavier tanks (no matter what size) and keeping a small wing?"

I dove some LP95s in the channel islands a couple months back and found them quite comfortable but they were a good pound or two more positive than all the HP100s I've been able to find specs for online.

I don't think it will be a major issue, just seeing if there are any people who already have this experience to help me "pre-weight" and hopefully know what to expect in general terms. In the end, it will all come down to my own comfort anyway.

 

[rhwestfall]

If you want the lift (not a bad thing) - sorry to put this in a different direction, but....

something like a OxyCheq Mach V wing is really a much smaller profile than many of the "similar" lift rated wings of that solves your dislike for the wing you tried... I own a HOG 32 single, a DSS 30# LCD, and an OxyCheq 30. the Oxy is significantly narrower. I like, but can't recomment the DSS LCD as the center hose is a PITA as it always is in conflict with the first stage.....

Some are saying that it may not be really 30#, but i don't know...

 

[KD8NPB]

Sherwood = Asahi = Spun Cylinder, which means the tank will be about -2 lb more negative than usual, and the heft is carried at the bottom of the cylinder.

 

[Dr. Lecter]

Sherwood = Asahi = Spun Cylinder, which means the tank will be about -2 lb more negative than usual, and the heft is carried at the bottom of the cylinder.

Not universally true, and the older Genesis HP100s will actually be about -2lb less negative than usual.

 

[Nemrod]

You know, I am pretty sure somebody told me the Oxy 18 was intended for aluminum 64/80 tanks. I know the vogue thing is negative steels but in warm water diving, with minimal exposure gear you can wind up negative just from the tank and no ditch-able weight. And very little lift reserve in the wing.

N

 

[fjpatrum]

You know, I am pretty sure somebody told me the Oxy 18 was intended for aluminum 64/80 tanks. I know the vogue thing is negative steels but in warm water diving, with minimal exposure gear you can wind up negative just from the tank and no ditch-able weight. And very little lift reserve in the wing.

N

This is exactly where I'm at when I start diving these big steels with my current wing. On paper I'm okay, with no integrated weight (actually no weight at all) but it leaves very little margin for error if I add anything negative to my kit.

 

[danvolker]

I have used my 18 pound Halcyon wing with HP100's and with LP 120's.....For either of these bigger tanks, it means using more than 3/4ths of the volume of the wing, to get neutral with a 2.5 mm near neutral freedive wetsuit on--at 60 to 100 feet neutral at the bottom, where neutral matters most to me.

So while the wing does the job fine for me....there have been 1 or 2 times when I had to help a novice diver on the surface, that had failed to inflate their own BC, was way to negative, and were flailing and panicked.....and I had to support them until I could get their BC inflated....This was a type of situation where my 18 pound wing was almost useless with the heavy steel tank on my back---fortunately with my freedive fins I could swim them to high elevation out of the water to calm them down, and have an easy time of getting their BC inflated. With an Al 80, my 18 pound wing would have had plenty of lift left over for this, but with the heavy steels, you don't have much margin for a near rescue on the surface.
In my case, usually I will use Al 80's, and my small wing is perfect. But if I was going to do alot of deeper divers with the heavy steels, and with lots of poorly skilled divers in groups around me ( not buddied to me), then I would probably decide I needed the 30 pound wing....which I have also
Given the use of the al 80...I will always go for minimum drag, meaning the 18 pound wing....and if the water was warm enough to use lycra or high tech non-buoyant exposure suits...I would consider perfect weighting and no wing at all.....even less drag!

 

[fnfalman]

This is exactly where I'm at when I start diving these big steels with my current wing. On paper I'm okay, with no integrated weight (actually no weight at all) but it leaves very little margin for error if I add anything negative to my kit.

That's why it's important to know what your gear selection and configuration is. Then calculate out the negative buoyancy and choose a wing that is big enough for it plus maybe 10-20% margin for error/safety.