Pull Dumps — lose them

[rsingler]

I think the idea is that if the hose has no pull dump feature then nobody should be yanking on it - so with a much gentler touch, there is less chance of failure????

Well, I had a guy bring in a bcd where the wire loop had just slipped out of the crimp. He hadn't pulled hard at all, according to him. But that wire should have been replaced years before. Probably never got looked at. Most techs do not disassemble the corrugated hose when servicing the inflator, though it should be noticeable inside the end.

I think almost everything that has been mentioned in this thread comes back to one of two common failure points:
Operator Error (as in the OP's comment)
Poor maintenance

I don't know how to reply to @boulderjohn when he says there's nothing to be done about this particular "instructor". Just means we need to look out for ourselves, even when seeking instruction, I guess.

And maintenance? Well, we see the whole spectrum here on the Board, don't we? From guys asking how to do things on the cheap (and maybe cutting corners), to folks willing to pay anything, but getting a bad reg back from service.

The military maintenance guys have the solutions: PMCS, and the T.O.
Used to laugh when I heard the sergeants grouse, "Do the Preventive Maintenance Checks and Services, and follow the damned Technical Order!" As usual, the sergeants were always right.

 

[guyharrisonphoto]

I think the idea is that if the hose has no pull dump feature then nobody should be yanking on it - so with a much gentler touch, there is less chance of failure????

Well, you are pulling between two "hard stops". The pin in the dump valve and the pin in the inflator assembly which is placed in the hard plastic. If the wire is the proper length, there should be no stress on the actual corrugated hose when you pull, because the wire will activate the valve before the corrugated hose extends enough to have pressure directly on it.

 

[johndiver999]

Agreed. In the past I have seen broken internal wires. It is a poor design. The wire is covered with a plastic jacket and a metal crimp is used. The crimp cuts through the
Plastic jacket and you invariably get corrosion and the wires always seem to fail sooner or later.

I generally replace the wire with very heavy fishing line with a strength of 2 or 300 lbs and this will never corrode and I have not seen a failure. Scuba pro uses a plastic rod which eliminates the crimped failure mod.

 

[CuzzA]

There must be different designs. Mine is a stainless steel aircraft cable. I think the breaking strength is 1,800 lbs.

It is as Guy described. A crimped loop. Push the stainless steel pin out on one side, reinstall through the loop and you're done. I can't imagine it ever failing before the corrugated hose.

 

[kelemvor]

There must be different designs. Mine is a stainless steel aircraft cable. I think the breaking strength is 1,800 lbs.

It is as Guy described. A crimped loop. Push the stainless steel pin out on one side, reinstall through the loop and you're done. I can't imagine it ever failing before the corrugated hose.

Did you sneak into my garage and photograph my gear last night?

 

[CuzzA]

Did you sneak into my garage and photograph my gear last night?

Haha, That Air2 5th gen is a nice reg. Breathes better than a lot of regs out there.

They get a bad rap for a poor performing history, but the new ones had to meet EU standards and perform excellent, IME. Right tool for the job, of course. Still hard to beat a necklaced octo setup though.

 

[Dan]

Old plastic screw in piece of the Zeagle Ranger bladder, where the pull dump screwed on to, can get brittle & crumbled. I have seen it happened on my buddy’s 20 (?) years old Zeagle Ranger. Last November during our 2-week LOB trip to Raja Ampat, during a dive, he pulled the power inflator to vent the air off his BCD and the whole pull dump assembly just came right off.

After the trip, I donated my 13 years old Zeagle Ranger to him. He took the bladder out of my BCD and put it into his (fortunately our BCD bladder sizes are the same). His BCD may have another 7 years before the screw in piece to crumble or may be longer if he quit yanking that dang power inflator. He’s a big guy (6’-4”) and may done yanking harder than the flimsy-old plastic thread can handle. That’s why I won’t do that yanking deal unless it’s an emergency.

 

[Dan]

Haha, That Air2 5th gen is a nice reg. Breathes better than a lot of regs out there.

They get a bad rap for a poor performing history, but the new ones had to meet EU standards and perform excellent, IME. Right tool for the job, of course. Still hard to beat a necklaced octo setup though.

The Air2 2 front button design always confuses me on which one is for inflate or deflate after 6 months of not using it. After 8 years, I bought Cressi with front button for inflate & bottom (or top if you raise it over your shoulder) button for deflate. No more confusion.

 

[Bob DBF]

I must be one of those divers, because I don't understand. Are you suggesting that we should be positively buoyant in the water to be properly weighted?

Not at all, however just because one can maintain a neutral stop does not mean that one is properly weighted. Not advising anyone to copy my behavior, but I was not weighted properly when hovering holding a 15# anchor I had found, before moving it up and over to the beach, but I was neutrally buoyant when hovering.

I chose to be overweighted, to recover the anchor, the diver in my last post didn't even know he was almost the same amount overweight. Even after he lost the weight he didn't see the issue because he just adjusted his buoyancy to compensate for the weight loss.

I check my weight by holding a 15' stop at 500# or less in my tank with an empty BC. This insures I can hold a stop when a dive is over. This will make me slightly buoyant on the surface but I can use my lungs volume to control my stop if I need to breathe the tank below 500# at 15'.

I was trained with no BC, so being slightly buoyant on the surface was a good thing, beats dropping a weight belt every dive.


Bob

 

[TrimixToo]

<snip>
I check my weight by holding a 15' stop at 500# or less in my tank with an empty BC. This insures I can hold a stop when a dive is over. This will make me slightly buoyant on the surface but I can use my lungs volume to control my stop if I need to breathe the tank below 500# at 15'.l

I was trained with no BC, so being slightly buoyant on the surface was a good thing, beats dropping a weight belt every dive.
Bob

Bingo! When you got your first BC, you probably mouth inflated it, too, a skill all too rarely seen today. I think that's still the best way to get near-perfect weighting in a wet suit.