Pull dump or non exhaust elbo

[plclark196]

Are pull dumps considered a potential failure point? If so, how do you exhaust - lower dump or power inflator dump- and where do you normally keep your left hand during a dive?

 

[cool_hardware52]

Are pull dumps considered a potential failure point? If so, how do you exhaust - lower dump or power inflator dump- and where do you normally keep your left hand during a dive?

Cable actuated pull dumps on at the "fill" fitting on your wing are considered a potential failure point.

These "rapid exhaust" valves can stick open, the cables can cut the corrugated hose, and repeated excessive yanking on the corrugated hose can pull the wing bladder through the outer shell.

The "pull dumps" or rapid exhaust valves are simply not necessary. Use a plain elbow.

Your wing can be vented either by pulling on the cord on the OPV, or by raising the corrugated hose and depressing the oral inflation button.

Tobin

 

[divestoclimb]

FWIW Michael Ange discusses a dive fatality in his book Diver Down that was peripherally related to a pull dump. The dump fell apart on the boat and the diver tried to put it back together, but he missed a part so the thing wouldn't hold air. He lost control of his buoyancy on a deep wall dive and...

Yes, he should have known what he was doing and he should have tested the BC after reassembly, but those things are needlessly complicated and this issue can be just as easily prevented by simplifying the gear.

 

[Jasonmh]

Are pull dumps considered a potential failure point? If so, how do you exhaust - lower dump or power inflator dump- and where do you normally keep your left hand during a dive?

Since this is the DIR forum, yes they are considered a potential failure point. I use both the lower dump and the power inflator dump, but primarily the lower dump. Where do I keep my left hand? Usually out in front of me where I can see it, and I reach back to dump from the bottom opv dump when I need to.

 

[rainman_02]

Normal elbow, no pull dump.

To dump, you do one of two things: 1) reach back for the butt dump and pull up and slightly out while being a little head-down; 2) reach up and dump from the inflator by lifting it up to your ear and possibly going slightly head-up.

I prefer the inflator dump when kicking around and ascending. I prefer the butt dump when scootering. You should be able to do either effortlessly.

 

[Greg Barlow]

Quite simply, pull dumps are a solution to a non-existent problem.

Greg Barlow

 

[dumpsterDiver]

Cable actuated pull dumps on at the "fill" fitting on your wing are considered a potential failure point.

These "rapid exhaust" valves can stick open, the cables can cut the corrugated hose, and repeated excessive yanking on the corrugated hose can pull the wing bladder through the outer shell.

The "pull dumps" or rapid exhaust valves are simply not necessary. Use a plain elbow.

Your wing can be vented either by pulling on the cord on the OPV, or by raising the corrugated hose and depressing the oral inflation button.

Tobin

I always use a pull dump in the inflator and have not seen any problems other than the steel cable corrodes and breaks eventually (why do the idiots use crimped steel cable, when crimped 300 lb monofilamnt fishing line would last forever and "never' fail or wear out?)

My other (more serious question) is why does a rear dump put less stress on the bladder that tugging on an inflator hose with a dump valve?


Also, I removed the rear dump string entirely, so I reduced a potential failure point too, right? string can't get caught if it is cut off..

 

[Vie]

...where do you normally keep your left hand during a dive?

The primary light is held in the left hand so it's usually in front of me.

 

[nadwidny]

I always use a pull dump in the inflator and have not seen any problems other than the steel cable corrodes and breaks eventually (why do the idiots use crimped steel cable, when crimped 300 lb monofilamnt fishing line would last forever and "never' fail or wear out?)

The OP said that pull dumps are potential failure points. So firstly let's take the "Potential" part out of "Potential Failure Point". In the fleet of gear we use for Scuba intros I've seen pull dumps fail more than a few times in ways ranging from diaphragms folding over, hoses tearing out, to the entire assembly coming off when pulled (and not just because it wasn't tightened down enough). To me "Potential " implies something may fail. Pulldumps will fail.

My other (more serious question) is why does a rear dump put less stress on the bladder that tugging on an inflator hose with a dump valve?

Leverage.

Also, I removed the rear dump string entirely, so I reduced a potential failure point too, right? string can't get caught if it is cut off..

There was a thread not too long ago that explained the difference between necessary and unnecessary failure points. I would suggest you go back and familiarize yourself with it.

 

[cool_hardware52]

Also, I removed the rear dump string entirely, so I reduced a potential failure point too, right? string can't get caught if it is cut off..

A power inflated "bag" with no Over Pressure Valve. Does that really sound like a good idea?

Tobin