BC hose "water plug?"

[Crush]

I have at times noticed what feels like a convulsion in my BC inflation hose when I shoot some air into it. I assume that there is water in the hose which is forced up the hose and into the bladder with the introduction of air under pressure. This is later shown to be at least plausible as I have to drain water out of the bladder at the end of the dive (perhaps a few hundred mils, or about 10 to 30 oz). The dive profile in this case is typically a see-saw.

Has anyone else experienced this?

Am I doing anything obviously wrong? Am I perhaps keeping the air dump button depressed too long, or perhaps I begin depressing it held high, and continue to hold it as I drop the hose down and let go of the button, thus allowing water to enter the hose?

Maybe a dump leaks?

It is not a huge problem, but losing a few pounds of lift matters if diving below 70 ft with a 24# bladder in a full 7mm two piece wetsuit.

 

[NC Wreck Diver]

I notice my AIR2 pounding air into my BC if I hit it hard. I thought it was water for a little while, but I think it's just the working pressure of the AIR2 hose (it's beefer than your typical BC LP inflator hose). Are you using an AIR2 type system?

I get a little water in my back back bladder from a typical dive. It seems to be when if vent my BC underwater. Maybe not 10-30 0Z's, but a small amount. As you mentioned, this seems like a lot. Check your dump valves for leaks. Remember, 16 OZ's of water is a pound. With water weight, an ounce of water is an ounce in dry measure too. Hence the old saying "A pint is a pound the world around (old bakery saying - but it's true)." Good luck finding out what the problem is.

 

[Bubbletrubble]

It's normal for a small amount of water to infiltrate the BCD bladder during the course of a dive. Are you doing comprehensive pre-dive BCD inspections? If so, then I wouldn't worry about it.

I don't think water is causing the "convulsion" when you initially add air to your BCD. After all, there should be no pre-existing water in the tank-first stage-inflater hose-power inflater-corrugated tube-bladder system. You're probably just feeling a forceful injection of air as it travels through the corrugated hose and into the bladder. This can happen with a lot of power inflaters if you depress the button fully and continue to hold it down.

 

[Crush]

It's normal for a small amount of water to infiltrate the BCD bladder during the course of a dive. Are you doing comprehensive pre-dive BCD inspections? If so, then I wouldn't worry about it.

Yes, and OK - thanks.

I don't think water is causing the "convulsion" when you initially add air to your BCD. After all, there should be no pre-existing water in the tank-first stage-inflater hose-power inflater-corrugated tube-bladder system. You're probably just feeling a forceful injection of air as it travels through the corrugated hose and into the bladder.

I notice my AIR2 pounding air into my BC if I hit it hard. I thought it was water for a little while, but I think it's just the working pressure of the AIR2 hose (it's beefer than your typical BC LP inflator hose). Are you using an AIR2 type system?

Similar answers from Bubbletrubble and NC Wreck Diver - perhaps the convulsion is not a plug of water, but only feels like one. Sometimes it is VERY pronounced, causing me to think - hey, something is off here. Not sure. Thanks for the food for thought.

 

[Bubbletrubble]

After all, there should be no pre-existing water in the tank-first stage-inflater hose-power inflater-corrugated tube-bladder system.

That's true... right up until the point that you vent your BCD to descend.

@RJP: For some reason, I thought that the "convulsion" the OP was referring to occurred prior to descent. A lot of shore divers inflate their BCDs more fully once they get into the water (at the surface). You're right, though. If the "convulsion" occurred underwater (after dumping air for initial descent), then it's possible that some water had already worked its way into the system.