Why do BCs take on water?

[Cacia]

Just when I think there is nothing new to say....I have never thought about the physics of this.


Well, the reason could include, Walter, sometimes trying to get new divers in current, to the bow and have them follow a descent line to a site.(to conserve air) Your method of going in negative is best if you are already a diver but some of these people seem to need a few minutes on the surface.

 

[cool_hardware52]

You hold your hose up? Don't you have a regular dump valve?

No, just a plain elbow and an OPV (rear dump)

Even if you have cable shoulder pull dump you can easily dump gas at the surface by raising your hose above the water and venting. If the end of the hose is out of the water, no water will enter the bc.


Tobin

 

[Walter]

Bad habit to get into when you have a right shoulder dump.

I've done quite a bit of teaching in those types of conditions, Catherine. I have a current line rigged to the tag line and I weight the tag line. They travel to the bow underwater.

 

[cool_hardware52]

Bad habit to get into when you have a right shoulder dump.

Walter,

If you are responding to me, could you please explain why it's a bad habit to dump from the hose at the surface? Many, many wings are sold with a plain elbow on the hose, and a rear OPV on the diver's left.

Tobin

 

[Cacia]

Bad habit to get into when you have a right shoulder dump.

I've done quite a bit of teaching in those types of conditions, Catherine. I have a current line rigged to the tag line and I weight the tag line. They travel to the bow underwater.

oh, yea. thats a good set up. I end up on all different boats. One guy has a horizontal line with a mushroom weight for a lateral safety stop position.

 

[Charlie99]

BC bladders seem to take on water, at least sometimes. Anybody know why or how to minimize the amount they ship? Is it poor technique?

You'll get a bit of water in if you are properly weighted and removed all of the air from your BC during the final stages of the dive, when you are shallower and your tank is lighter.

If you are getting excessive amounts of water in, then you are probably either trying to dump air from the point that isn't the highest, or you keep trying to dump air even after all of the air is out. (The latter one used to be my problem).

A bit of water in the bladder isn't a problem. It doesn't affect your buoyancy. The only downside is that it adds weight to your BC that you have to haul up a boat ladder or back through the surf. Just pull a lower dump to dump the water once you are standing on the beach or boat.

 

[Goose75]

I never undertood that concept anyway - you want to get in the water and descend below it, inflating your BC forces you to not do what you want to do. Check your gear on the boat and don't get in the water before you're ready.

I typically surface swim to a decent point.

 

[BuoyantC]

Back to the original question of water in the BC, awap and Charlie99 are on the right track. If you are light and try to dump that last bit of air to stay down, water is going to enter the BC.

D.C.C.

 

[Masterfish]

If you don't inflate your BC prior to entering the water, you'll eliminate most of the problem.

I never undertood that concept anyway - you want to get in the water and descend below it, inflating your BC forces you to not do what you want to do. Check your gear on the boat and don't get in the water before you're ready.

not everyone dives from a boat, down here in Australia, alot of divers in the Sydney area perform shore dives, if you've never been here, you'll know that we have alot of beaches and rockey headlands, there's no way in heck im belly-flopping or giant-striding off a rock ledge into a swell and paddling out 30-100m or so to reach an appropriate decent point WITHOUT air in my BCD. At the start of this type of dive, my BCD helps prevent me from sinking into/bobbing around in, near or ontop the rocks. an inflated BCD allows me to fin briskly out to a safer and more appropriate decent point without wasting air on my reg (snorkel out after initially using reg to enter water in the rougher conditions).

not everyone is wealthy enough to have access to regular boat dives, or to own their own boat...

 

[DennisW]

In any case, if you get water in your BC or not, (You will no matter what you do anyway.) you should rinse the inside of your BC with fresh water after use.