Air locked in bcd

[FernandoF]

This is something that happened quite a few and would like to hear your comments.

Sometimes air gets locked in the bcd while diving. I try to dump air but nothing gets released. Only when I change position, usually by "standing up", air is released. I'm using hired bcd and although it happened with all the models I used, I think the older ones have more tendency to lock air.

Is it something that is supposed to happen or is there anything I'm doing wrong? Also, I only use jack-style bcd - is back-inflated more responsive with air flow in & out?

[oddbod]

Air rises to its highest point and may get trapped in one side of the bladder, so by going vertical you're allowing it to escape, the highest point becomes the inflator. When not vertical try rolling around slightly , ie: if the dump is on the right side roll slightly left side and slowly back to right up to get air to move from the left. A donut shaped back inflate/wing will allow air to flow around and not get easily trapped.

[navyhmc]

Can't get better than oddbod's explanation...I was writing the same thing-he's faster on the keyboard.

[tedwhiteva]

For most BCs, roll left shoulder up as you raise the hose towards the surface and dump

[FernandoF]

yeah, seems logical - I'll give it a try. And I know have another reason to prefer back inflated (but that's for another post).
Thanks for the responses

[mm2002]

Another consideration is fine tuning your buoyancy/weighting. The more over-weighted you are, the more air you'll need in the BC, and in turn, the more problems you may have getting it all out.

[CompuDude]

Generally if your BC has exhaust valves in the back, those are easier to dump from without changing your position as radically as needed to use the shoulder dump.

As noted above, air will always seek the highest point, so if your dump valve is lower than the bubble, that bubble ain't going anywhere.

So with the inflator hose, you'll need to raise that hose by changing body position so the connector on the back is the highest point, and the end of the hose (the inflator in your hand) is higher than that. Only then will the bubble exit. I generally prefer to use the rear dumps for this very reason... just stick your bum up a little so air goes to the back, pull the little dump string, and air exists with much less contorting.

[Skred]

You indicated that the BC you're using is a rental. Does it even have a rear dump valve? I have seen rentals that don't.

[FernandoF]

Originally Posted by Skred

You indicated that the BC you're using is a rental. Does it even have a rear dump valve? I have seen rentals that don't.

mostly, it's only a cup to place a dump
I actually thought of using the rear dump already and when I got a bcd with rear dump I found it to be a bit difficult. I mean, it takes time getting used to the amount of pressure to apply, not like the deflator button in the power inflator, and I ended up dumping much more air than needed when using the rear dump.
Then again, I guess getting used to that will be much easier once I'll be using my own gear.

[CompuDude]

Originally Posted by FernandoF

mostly, it's only a cup to place a dump
I actually thought of using the rear dump already and when I got a bcd with rear dump I found it to be a bit difficult. I mean, it takes time getting used to the amount of pressure to apply, not like the deflator button in the power inflator, and I ended up dumping much more air than needed when using the rear dump.
Then again, I guess getting used to that will be much easier once I'll be using my own gear.

Yup, that's one of the better reasons to own your own gear.