Horseshoe wing & dump valves

[freename]

I bought a set of used doubles a while back, complete with BP&W, and finally had my first opportunity to dive it this last weekend. The wing is a horseshoe shape, unfortunately, rather than the doughnut that I've become well acquainted with and fond of. I kept finding that air would get trapped in the right hand side and require some awkward body rolls to move the bubble to where it could be vented (go vertical to get the air to the top, roll right to get the air left, face down to get the air to my *ss - or just vent it in that awful trim position). Initially, I was thinking that I may have to replace the whole wing, but one of the people I was with asked me why I don't just have another dump valve added to the right side.

Because I haven't had a chance to make it into a dive shop yet (and probably won't for a couple days at least), I thought I'd post a couple of questions here:

• Is adding another dump valve possible / easy / affordable / realistic?
  
• Am I just doing something wrong in how I'm wearing / using this thing? Or are my pains real? Ha!
• Even if I do get a second dump valve installed, am I still going to be frustrated by uneven air pockets in the bladder? Should I just scrap the whole thing now?

Thanks!

 

[stuartv]

That's why I don't like horseshoes. I have 3 doubles wings. 2 are horseshoes. I pretty much only use the donut one. I'm selling one of the horseshoes and keeping one just as a backup.

 

[runsongas]

do you go head down when dumping air? if so, just try dumping while horizontal or even slightly head up. i have both horseshoe wings and donut wings and the horseshoe wings dive just fine.

 

[tbone1004]

If you're horizontal, rolling to the right is usually sufficient. I have no problem with horseshoe wings and actually prefer them, especially in technical diving as they allow you to pack air in one side or the other. If you are head down *common problem in doubles btw* it is obviously not possible to transfer all of the gas, but you shouldn't have that much trouble if you are flat. Worst case you go slightly head up *only a few degrees*, then while you're up roll to the right and come back to flat and it should be almost all in the left side

 

[freename]

I think I'm fairly level... most feedback I've had seems to suggest I'm diving properly trimmed, but then again I haven't seen video and am often not diving with tech-level / style divers so it's entirely possible that they're just... not picky enough?

I suppose it's also entirely possible that I'm exaggerating some of the movements because I'm still getting familiar with the equipment (and style of wing), and because the wing is (I suspect) larger than needed so the air is less inclined to find its way to the exit. I did find myself having to go a bit head-down to dump the air at points since the bubble just didn't seem to want to move all the way back. That tended to be when the bladder was emptier and I was trying to get those last little bits out... which was also when the air seemed to get trapped in the right side more. It was more of a nuisance than anything... but still, I'd rather not have nuisances if I can find ways to avoid them.

I have no problem with horseshoe wings and actually prefer them, especially in technical diving as they allow you to pack air in one side or the other.

Forgive my ignorance... maybe I haven't thought this through enough (and am almost certainly more naive than I should be - I haven't even *quite* finished my intro to tech yet), but I'm struggling with seeing a point when I would want to have only one side packed. What sort situations would you want to use this in? I guess maybe if you had your weight distributed unevenly... say, you had stages that you were dropping off or picking up?

 

[tbone1004]

how big is the wing, and what tanks/exposure protection are you using? Steel plate or kydex/aluminum type plate?

and in terms of being offbalance:
stage/deco bottles *especially if you subscribe to the GUE/DIR style of everything on the left
big canister lights *not a thing anymore, but they used to be*
expedition reels etc
OOA issues if you have to isolate *shouldn't have to, but if you do*

 

[cool_hardware52]

I suppose it's also entirely possible that I'm exaggerating some of the movements because I'm still getting familiar with the equipment (and style of wing), and because the wing is (I suspect) larger than needed so the air is less inclined to find its way to the exit. I did find myself having to go a bit head-down to dump the air at points since the bubble just didn't seem to want to move all the way back. That tended to be when the bladder was emptier and I was trying to get those last little bits out... which was also when the air seemed to get trapped in the right side more. It was more of a nuisance than anything... but still, I'd rather not have nuisances if I can find ways to avoid them.

A couple things to keep in mind in no particular order.

Doubles involve greater gas loads, and that means more gas in the wing period. Bubble management is more work when you have 16-24 lbs of gas vs 6 lbs in an al 80.

Doubles wings are frequently waaay to big, and that results in lots of tank wrap. Tank wrap never improves venting.

The lower arc of a donut wing is under the lower end of your tanks, i.e. between the tanks and your butt.

Gas *always* goes to the high point in any wing, and in any wing, horseshoe or donut the highest point will be on the sides, unless you are about 70 degrees heads down. Even with a donut wing gas isn't going to go down hill and under the lower end of your tanks.

Currently we offer 4 sizes of doubles wings, and all happen to be donuts, but not because they offer any particular advantage. We have produced horseshoe wings, and still can on demand. I frequently dive a horseshoe doubles wing.

Given that gas only moves through the lower arc of a donut wing when you are ~70 degrees heads down it's easy to keep more gas on one side than the other, if you need to.

We taken the bladders out of donut wings and rf welded the lower arc shut, installed them in shells and test divers could not tell the difference for the simple reason that gas almost never moves from side to side through the lower arc.

When ascending in a dry suit you will need to occassionally raise your shoulder to vent the suit. When you do this the wing will move gas through the top arc. Remember the top arc isn't trapped under the cylinders it can roll up until it hits the valves and 1st stages. That means much less heads up is needed to shift gas via the top arc than via the bottom arc.

If your current wing is not grossly over sized you probably simply need more practice.

Good luck,

Tobin

 

[Doby45]

I was going to mention some of the "Donut Fable" that Tobin did, but he is so much better at it than me. I currently have a horseshoe wing and I have no issues with dumping air or gas transfers or any of that other black magic stuff.

 

[Nirvana]

As Doby45, I dive a doughnut shaped wing and I do not have any problem venting air through the back dump or balancing the wing. I believe the problems you are having do not arise from the shape of the wing.