Knobs on dump valves?

[landphil]

I will say, I’ve been on multiple dives where someone’s dump valve pull string (for a shoulder dump, on a Hydros BCD if I remember right) got stuck under a strap and was holding the dump valve open. One of those occasions, it was actually somewhat dramatic, with the person unable to establish positive buoyancy on the surface and getting churned by big-ish waves. That sold me on dump valve toggles being a bad idea.

I dive with drygloves year round I don’t find finding the dump valve hard, even with deco bottles on the left. With a little practice, it’s easy to find, although replacing the stock string with something a bit stiffer/thicker does help.

That was my wife's state 90% of the time right after putting on her Hydros BC. But that's an especially problematic dump string, made worse by Scubapro's odd ideas of how women are shaped. We've both moved to BPWs, so no more shoulder dump strings. I don't remember seeing any issues with the butt dump toggle or string getting tangled with the BC, though.

 

[inquis]

I have a figure-8 knot as close to the housing as I can (perhaps 1/4" or 6mm). I find the housing, then the knot with thumb and index fingers, then just pinch to let a spurt of air out. I almost never need to "pull hard" for a substantial release of gas, but I guess I could if needed.

The knot close to the housing allows precision venting. I can feel it with or without dry gloves.

 

[happy-diver]

No knob required.

During my first course with @kierentec I noticed how he used all his fingers to first locate the OPV and then he used his index finger to spool the cord around it for a precise burp of his wing.

There's nothing like some thinking mans dump string pulling in the morning

Especially with some thick strong string with integrated stiffness for twidling

Where the dump is actually the knob which you find first then pull the string