Horse shoe or donut?

[Flycaster]

Horse shoe or donut? What do you prefer the horse shoe sale when are the donut?
I would think in Siri the known it would tend to tip you forward slightly further than a horseshoe .

 

[stuartv]

I prefer a donut. Horseshoe wings that I have used only have a butt dump on the left side.

I have had it happen that I was in a head down position and wanted to dump air, but couldn't dump enough because half the air was trapped on the right side.

Plus, all factors being equal, including identical lift capacity, a donut wing will be shorter, thus making it less likely to roll under the bottom of the back plate, if/when you remove the BPW from a tank and drop it (by accident). I have gotten a pinch flat in my wing from doing that.

I don't think it makes any difference whatsoever to tipping your forward on the surface (if that's what you were talking about).

If you were talking about tipping forward when trying to be in horizontal trim, I also don't think horseshoe vs donut matters. I've had both styles that gave me good trim and both styles that tended to make me go head down and thus needed a tail weight. That is down to the specific design of the individual wing.

 

[Eric Sedletzky]

The time when a donut wing is nice is when you are tail up and want to dump air. I also like donut wings with 360 loop zippers for thorough cleaning and self repairs if needed.
I also like the inflator hose to come out if the left side so that it doesn't interfere with my 1st stage.

 

[drbill]

I've dived both over the years. As a videographer I much prefer donuts for the air dumping reasons mentioned previously.

 

[cool_hardware52]

Horse shoe or donut? What do you prefer the horse shoe sale when are the donut?
I would think in Siri the known it would tend to tip you forward slightly further than a horseshoe .

Wings only provide lift based on where the gas is in them. For a horizontal diver how much gas will be in the lower arc of a donut wing, the part *under* the lower end of the cylinder?

Where ever a wing is widest, in plan view, is where the first puff of gas will end up for a horizontal diver. It's possible to shape a donut wing to be wider near the diver's shoulders, mid torso, or at the waist. It all depends on what the application needs.

BTW, for a horizontal diver gas doesn't magically go down under the bottom of the cylinder and back up to the other side. To shift gas through the bottom arc of a donut wing requires the diver be ~70 degrees heads down. Remember gas always goes to the high point in a wing, always. To fill the lower arc, the part *under* the lower end of the cylinder you need to make it the high point......

What makes a wing easy to vent or hard to vent is the amount of tank wrap, not horseshoe vs donut.

Tobin

 

[Flycaster]

Horse shoe or donut? What do you prefer the horse shoe sale when are the donut?
I would think in Siri the known it would tend to tip you forward slightly further than a horseshoe .

I think my auto-correct really butchered this post. I apologize to all for this.

It should have read " What do you prefer the horse shoe or donut style BC?"
"I would think the donut might have a bit more forward tilt than a horse shoe"

 

[cool_hardware52]

I think my auto-correct really butchered this post. I apologize to all for this.

It should have read " What do you prefer the horse shoe or donut style BC?"
"I would think the donut might have a bit more forward tilt than a horse shoe"

Same answer, wings provide lift where there is gas in them. No gas in the lower arc of a donut for a horizontally trimmed diver.

Years ago we removed the bladders from a couple donut wings and welded the lower arc shut, effectively making them horseshoes. Reassembled the wing and gave them to divers to compare to unwelded donuts. Not one reported any difference in the water.

Gas just does not abandon the laws of physics when it realizes it's inside a "donut" wing.....

Tobin

 

[Damselfish]

I dive in all sorts of positions, not just horizontal. Given top and bottom dump valves I will use them about equally. If I've got no separate top dump I will usually go butt up to dump. (I just don't like dumping from the hose. or any pull dump that involves the hose.) My current BC is an Express Tech, which is a horseshoe. It's saving grace is that it has a bottom dump on each side, but I'd rather a donut so I didn't need to use 2 dumps. Also so I couldn't wind up with more air on one side and have to mess around sorting that out. Not that I generally have much air in it, but doesn't take much to notice. My last BC had a donut, which I much preferred.

 

[cool_hardware52]

What makes a wing easy to dump or hard to dump is the amount of tank wrap, the tank is the hot dog and the wing is the bun. Wings with wide center panels (the part of the wing that does not inflate) and or waay too much capacity will wrap the cylinder and put the "bubble" well above the centerline of the tank, sometimes above the tank period. That requires the dive to go vertical to dump gas, regardless of if it's a horseshoe or donut.

All DSS wings have a 3 inch wide center panel, horseshoe or donut.

Lots of folks have had the experience of diving with a back inflate BC or poorly designed horseshoe wing wiith lots of tank wrap, and then a more narrow donut. That leads them to attribute magical properties to the donut, but it's a function of tank wrap.

Take a look at some back inflate BC's The center panels are often 6-10 inches wide. It's a matter of good design.

Tobin