Water in BCD

[Frosty]

Hey folks .My kids and I were packing up after a dive and as per usual about half a litre of water sloshed out of my BC.
Mr 10 then told me how dangerous that was because it made the BC heavier.
Mr 14 then corrected him saying of course that water weight in water is effectively zero. -All pretty normal stuff
But then smart alec mr 15 says something that got me thinking. He said
"yea but it reduces the AVAILABLE lift in your BC"
Ok so most times with correct weighting etc a recreational diver really doesn't need all the lift in their BC
But how would you get rid of the water out of your BC during a dive if you were getting up towards its lift limit?
Mine has a butt dump so its fairly easy to pump it up -pull the butt dump and let the air pressure expel most of the water. How would it work with other BC's??

 

[underH2Oman]

The water generally enters the BC when you are dumping air during an ascent. If you are descending you only add air to make yourself neutral. Your only concern would be if you go deeper than your BC can compensate for.
If your BC has 16kg lift empty if you put half a litre of water in, it will have 15.5kg of lift. I would not be worried about .5kg in the water.

 

[nimoh]

I agree it isn't worth worrying about, especially since you shouldn't be all that negative with an empty BC, and having a BC full of water would be the same as an empty BC.

If your BC was full of water, but otherwise functional, you could invert yourself (head down vertical) and hold both buttons forcing the water out or you could go head up vertical and hold the inflator button while simultaneously keeping the bottom dump valve open, also forcing the water out. Whether or not the problem is fixed, I would still probably end the dive since it is such an odd thing to happen, and so something is obviously wrong. So, because I would end the dive anyway, I probably wouldn't try to fix the problem, but just swim up making appropriate stops, and then figure out what went wrong on the surface.

 

[redacted]

While some water is normal, a pint is a bit much. You may want to look at dump valve operating techniques and weight requirements. If the dump valve is activated and bubbles are not coming out, then water is going in. If one is frequently activating the dump valve with little air being released, then there may be a problem with position or with weighting.

 

[TMHeimer]

There was a thread a while ago on this. I've never thought about the water in there, and to be honest have no idea if it can be expelled underwater. If you are diving in the tropics with only a body suit or rash guard and a steel tank, I've heard stuff like this may cause problems. I've heard it is advisable to have a BC with 2 bladders for such diving (in case one rips, or fills with water?)--you don't want to be negatively buoyant even after you have to drop weights. I'm no expert on this.

 

[scubadada]

I empty out my BC after every dive on the boat by pulling the rear dump while I'm gettting out of my rig. This is an automatic function for me, regardless of the importance of water in my BC.

 

[serpentara]

In theory when you inflate your bcd, it should push excess water out your purge valve. Your bc should have one at the bottom so you can vent air from a feet up position. When you add air when oriented upright, the air should pool at the top forcing the water towards the bottom valve. As you add more air to increase buoyancy, the air you add should at some point overcome the spring pressure of the valve, forcing water out and replacing it with compressed air.

Even easier is to just hold open the bottom valve as you inflate the bcd. It would use less air that way since you would mot have to build up to overcome spring pressure.

 

[tracydr]

I was having trouble with this in my BC. Turned out it had a leak and wasn't holding air well. It couldn't even float on the surface with an empty steel tank when I finally retired it.

 

[Splitlip]

Which ever of the dumps you're using during the dive, be certain that dump is at the high part of the bc where the bubble will naturally migrate. Head down, butt dump. Head up, shoulder dump.

 

[Nemrod]

My most used wing barely displaces 18 pounds, if that. Amazing that once upon a time, divers did fine with no BC, some still do. A little water in the BC is no harm and is normal.

N