Quick air dump from rear dump on horseshoe wing?

[DiverGuam]

Slightly OT, but I'll ask here. On my jacket BC I've got the bottom dump on a pull cord, and the shoulder one I can either pull the inflation hose, or raise the hose up to vent. The shoulder also acts as a 'blow off valve' to keep a stuck low pressure inflation valve from popping the bladder.

Do wings work the same way? Can you vent by pulling the inflation hose? Do they have a blow off type valve? Or is it a model specific thing.

Inquiring minds want to know, and I'm not trying to thread jack ya.

Steve

Here's the deal with pull dumps in the inflator hose: If they exhaust flapper fails, then you have no way of keeping air in the bladder. That also goes for the string pull dump to a lesser degree, and it is also the reason why wings usually put the bottom pull dump on the inside of the wing.

Some people go ahead and put pull dump elbows on their wings because they feel the slight risk of pull dump failure is less of an issue than ease of use is.

 

[g1138]

From a prone position, can't you just roll right while slightly head up, then invert down to push all air to the side where you rear dump is?

If you keep your legs tucked to your chest and pull the dump as soon as you go from your roll to your dive, I think it should help you get a little momentum for the poor form duck dive.


Other option would be to start the deflate from the inflator hose while vertical, then cartwheel once your head is below the water and go to the rear dump. The cartwheel should bring all air to one side.

 

[James R]

I think you may be manufacturing a scenario in your mind that's unlikely to ever be required. A couple seconds to dump most of the air while still vertical at the surface probably will not make much, if any, difference. Also, you need to consider how fast you can descend while keeping your ears equalized.

I can only recall descending rapidly once, and it was something of my own doing that caused it. I dropped a relatively negative OMS slipstream fin and chased it down with one fin on and a partially flooded mask. I could have taken my time, but in the moment I was afraid it was going to go beyond a depth where I could safely retrieve it using a single tank (wall dive). It stopped at 75fsw or so IIRC.

 

[Malpaso]

I think you may be manufacturing a scenario in your mind that's unlikely to ever be required.

I'm good at that!

 

[MikeFerrara]

Maybe I misunderstood TSandM but the idea behind descending and ascending in a horizontal position is that it provides for a great deal of control in ALL directions. Up/down with buoyancy control and fore/aft with the fins. Additionally, when you do it that way, you're never far from being neutral which makes it easy to halt the ascent or descent and maintain depth when needed.

The ascent and descent are "dynamic" portions of the dive where problems are most common. Consider the case where your buddy has a problem mid-ascent or descent and you're vertical and maybe significantly negative. It's a lot of extra effort to swim to them (have to get horizontal to swim very well) and then you still get there very negative. Now you have to kick like crazy (at just the right rate) just to maintain your depth.

If you were horizontal, it would take one flip of your fins to put you nose to nose. You're close to neutral so a deep breath and/or a little shot of air to the BC halts the descent.

Something else to try is a timed descent or ascent. It's about control.

---------- Post added June 26th, 2014 at 02:45 PM ----------

I like the idea of a rear dump but I never really used mine all that much. The reason is that I like hearing/feeling the amount of air that I was letting out and just could never do that quite as well as with the inflator.

I have to say something about descending. IMO, the best way for most situations is to get neutral and exhale. You'll be adding air back by the time you drop very far.

The worst way for most situations is to dump ALL your air and start dropping like a rock. Remember, "properly weighted", you're several pounds overweight at the start of a dive (the weight of the air you're carrying).

 

[DiverGuam]

IMO, the best way for most situations is to get neutral and exhale. You'll be adding air back by the time you drop very far.

The worst way for most situations is to dump ALL your air and start dropping like a rock. Remember, "properly weighted", you're several pounds overweight at the start of a dive (the weight of the air you're carrying).

What is really cool about teaching in really warm water is that many students do not even have suits to lose buoyancy on descent, which means they can only have to worry about the buoyancy swing from the tank full to empty.

 

[drbill]

I've always preferred donut wings over horseshoes for this very reason. As a videographer, I am frequently deflating and then reinflating my wing as I locate new subjects to film. Horsehoes just don't cut it for me.

 

[dmoore19]

My back-inflate has a dump on each side of the horseshoe. I can dump them both at the same time while going down head first.