Balance BC Trapping Air?

[pjerl]

I dove with my new SeaQuest Balance BC for the first time yesterday. On both dives I had trouble maintaining a controlled ascent once I got above 20'. There must have been air trapped somewhere, either in the bc or in between the bc and my body. I started pulling every dump I could find, but the bc would not let any more air out.

On my second dive, I added an extra couple of lbs, but still had the issue.

Has any one experienced this before with this bc? Any ideas of where or why the air is getting trapped?

 

[Dannybot]

I have a Balance, I have experienced it a few times. Usually I can get horizontal and roll counterclockwise and then purge from the rear dump. Alternatively, get vertical and lift the inflator, or pull to dump. I find pulling works a little better, since there seems to be a significant delay as the fill tube purges the water in it near the valve. Hopefully this helps.

P.S. How new is your Balance? the 2007 model has a right shoulder dump, which may help with the positioning and rolling.

 

[pjerl]

thanks. It does have a dump on the right shoulder, It didn't seem to help much. Other than that, I like the BC. It's really comfortable.

 

[evil_xander]

Other than that, I like the BC. It's really comfortable.

Whereas others as a standard feature have steel spikes poking the diver?

As long as it's comfortable I guess it's ok, trapping air is no biggie...

 

[spectrum]

Adding a couple of pounds is nice but it's not a weight check. You could still be under weighted.

What BC were you using prior with which you determined your weight requirement?

Many BCS do have tricks to them I tried a Sherwood Outback once and was shown that to get rid of that last burp I needed to lean it back counter intuitively. When valves are in relationship to top dead venter can be distorted when in the water column and looking through a mask.

Try planning a drill with a buddy watching where you attempt to get valves at top dead center and vent from them.

Pete

 

[halocline]

You might check the positive buoyancy of the empty BC by seeing how much weight it takes to sink it on it's own. You might be surprised by how buoyant it is.

 

[pjerl]

Thanks. I'll give it a try...although I am not having issues when I just get in. I can hang at 10 - 20 ft with no problem on descent. The problem really occurs on ascent, thats why I think air is getting trapped somewhere.

 

[spectrum]

Remember that air weighs about .08 pounds per cubic foot.

If you made a dive with an AL80 cylinder and are coming back with 750 PSI you are now 4.65 pounds more buoyant due to the reduction of air contents. This will apply to any mid size single cylinder with slight variations in the math. Beyond that the swing will be less or more.

That is why your weight check must be done at the end of the dive or you pad an extra 5 pounds on your weight total to account for usage.

Pete

 

[pjerl]

Thanks..starting to make more sense. Although the issue was more dramatic the other day, I have experienced this before with other BCs...this would go a long way to explain things.

 

[Warmwater Wank]

Could still be trapping some air. Take a look at the air cell around the tank area when you don't have the bc on. That "horse collar" top area of the bladder will hold a bit of air across the shoulder region if you stay perfectly vertical on ascent. You'll learn to sort of roll one shoulder higher than the other to get the air to rise up to one of the shoulder dumps--and since there is a right shoulder dump, I use that. (On a horizontal ascent, a bit of air could get trapped at rear of cell but it's easy to tilt up a bit and keep the air forward.) BTW, the left shoulder dump is not only controlled by the inflator air release valve, it also has a cable connected to the inflator itself. If you pull down on the inflator, it will dump air from the shoilder valve just like the right side does. Means you don't have to raise the inflator itself up higher to vent out of it. The first few times may feel like you could pull everything apart at the inflator but you won't! Nice bc. Very comfortable, also very stable w/ a tank attch'd. if you have to walk around much for shore diving etc. Slightly bouyant but only by a couple pounds. // ww