Water in Wing

[dumpsterDiver]

No one seems to be addressing what I see as the real problem here. It sounds like this is the first time you have ever emptied your wing bladder after a day of diving. Even if it doesn't feel heavy, proper maintenance after salt water diving is to add water inside the bladder, swish it around, drain it, blow air in, drain it again, and then partially fill it with air and hang it to dry. The inside of a wing is just as important to rinse as the outside. If your wing is starting to get more and more water in it with each dive, there is a leak. It might be the bladder. But it is just as likely that leak could be from the OPV or inflator valves that are crusted with salt from lack of proper maintenance.

Well not exactly...I prefer to FIRST blow it up all the way, then try to vent as much saltwater as possible, THEN add fresh water and rinse and dump. I think you get more salt out if you dump the straight saltwater out first...

 

[phoenix31tt]

Well not exactly...I prefer to FIRST blow it up all the way, then try to vent as much saltwater as possible, THEN add fresh water and rinse and dump. I think you get more salt out if you dump the straight saltwater out first...

same

What causes water to enter a BC is the corrugated hose. There is a bit of water sitting on top of the oral inflate valve / quick dump valve (if so equipped)

When these valves are opened this water runs down the corrugated hose as the gas flow out, the force at play is gravity.

The more often you dump gas the more water you will have in the BC at the end of the dive.

i don't use my corrugated hose to dump at all with my wing and i find i have more water in it than when i was diving a jacket... i dumped via the corrugated with the jacket

the biggest difference between the jacket and my wing is that i barely have any air in my wing for most of the dive and probably none in it when i end a dive...

 

[kwinter]

Well not exactly...I prefer to FIRST blow it up all the way, then try to vent as much saltwater as possible, THEN add fresh water and rinse and dump. I think you get more salt out if you dump the straight saltwater out first...

Yeah, I thought that dumping the salt water out first was self evident. Jeez, you're a picky bastard.

 

[cool_hardware52]

same




i don't use my corrugated hose to dump at all with my wing and i find i have more water in it than when i was diving a jacket... i dumped via the corrugated with the jacket

the biggest difference between the jacket and my wing is that i barely have any air in my wing for most of the dive and probably none in it when i end a dive...

For those that persist in believing that trying to dump gas from a BC when it's empty is what causes water to enter should try this:

Take an empty paper shopping bag, flattened out, and lay it on the table. Apparently it should fill with air all on it's own.

They don't of course for the very same reasons I've detailed, no pressure differential from inside the bag to outside the bag.

As I mentioned even OPVs will allow water to enter the bladder, just less than the typical oral inflate on a corrugated hose.

What people fail to grasp is that water can flow into the bladder at the same time gas is escaping. The gas isn't forced out at high pressure or flows, it only leaves because it's less dense than the water, the gas flows up and the water flows down at the same time.

Once a BC is completely empty of gas no more water will enter. The bladder is collapsed, just like the baggie I referenced in my previous post.

Tobin

 

[phoenix31tt]

For those that persist in believing that trying to dump gas from a BC when it's empty is what causes water to enter should try this:

Not one of those people... Was just saying that not using my corrugated hose didn't decrease water intake...

So for me the pull dump let's in water just as easily...

It was hard for me to believe that it's pulling the dump when empty that was letting the water in as I rarely pull the dump when it's empty already (maybe for the 2 sec it takes for me to ensure the wing is empty)


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[kwinter]

I think Tobin is also referring to the venturi effect that will draw water into the wing from anyplace it can while you are venting. So whether you vent gas by pulling on the corrugated hose or using the manual inflate/deflate button or using the pull dump on the bottom doesn't matter. As gas exits from one orifice, it causes a venturi flow that will draw water in from any other.

 

[phoenix31tt]

I think Tobin is also referring to the venturi effect that will draw water into the wing from anyplace it can while you are venting. So whether you vent gas by pulling on the corrugated hose or using the manual inflate/deflate button or using the pull dump on the bottom doesn't matter. As gas exits from one orifice, it causes a venturi flow that will draw water in from any other.

I'm not sure that's quite accurate... Wouldn't the valve on the inflator prevent water from entering?...

But I agree that water enters as air exits... Be it corrugated hose or pull dump...

Wing does not need to be empty.... It's easy to test by putting an empty wing in a tub and pulling the dump... Barely any water gets in... So I completely agree with what he's saying wrt empty wings


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[The Chairman]

There is no substantial pressure differential to keep water out of the BC. Once you've opened an orifice for air to escape, water will always try to replace it. It's not a one to one relationship because water is 784 times denser than air at sea level. The deeper you get, the less differential there is, but it is always significant. The stiffer the bladder, the less the pressure differential will have an effect and the more that water will sneak in.. It's simple physics. Either way, it's impossible to vent a BC under water without letting in a modicum of water and this will accumulate if you don't drain it between dives. There are techniques which can limit the amount of water you let in, but nothing that can totally eliminate it.

 

[cool_hardware52]

I'm not sure that's quite accurate... Wouldn't the valve on the inflator prevent water from entering?...

How? The oral inflate / deflate in the typical power inflator is an oring sealed poppet. If the oring is off it's seat how can it allow gas to flow in one direction and stop water from flowing in the other?

Tobin

---------- Post added October 18th, 2015 at 08:30 AM ----------

There is no substantial pressure differential to keep water out of the BC. Once you've opened an orifice for air to escape, water will always try to replace it. It's not a one to one relationship because water is 784 times denser than air at sea level. The deeper you get, the less differential there is, but it is always significant. The stiffer the bladder, the less the pressure differential will have an effect and the more that water will sneak in.. It's simple physics. Either way, it's impossible to vent a BC under water without letting in a modicum of water and this will accumulate if you don't drain it between dives. There are techniques which can limit the amount of water you let in, but nothing that can totally eliminate it.

Not impossible, just impractical. If gas is *forced* out of a orifice at the bottom of a container under water no water would enter. It's gravity and the density differential that causes water to enter a BC that is being vented from a High point.

Of course divers don't force out gas.

It would be fun to secure a BC (with no diver in it) under water and fill it to the point where the OPV vents and see how much water enters vs simply venting it.

Tobin

 

[dumpsterDiver]

I'm not sure about your BP/W, but I am pretty sure some of the older pull dump assemblies on normal BC's included a one way check valve - butterfly valve - whatever you call them - same as the exhaust valve on a regulator.. Sea quest had it i think, not sure of they still do? But this should stop the exchange of air and water, yes?