Does a pull-dump stress the corrugated hose flange?

[Web Monkey]

I have seen students break a shoulder dump by pulling too hard. The result is a large and instant leak high in the wing or BC that precludes the ability to trap any air. In short, you get a total wing/BC failure.

Hey! I resemble that remark! Did exactly that on my #7 dive in Cozumel. Ripped it right off and all the air came out.

Happily, I wasn't over-weighted, since it's apparently a long way down the wall.

Terry

 

[Indian Valley Scuba]

The stress is on the stainless pin and cable running inside the hose assembly. There is no significant stress on the corrugated hose itself. And the valve opens with minimal effort, so unless you are hanging on the hose, there is no reason to worry about all the other issues listed above.

Just dive!

 

[carrielsal]

So I'm still waiting on an answer from the OP why he would want a pull dump.

 

[James R]

So I'm still waiting on an answer from the OP why he would want a pull dump.

Some of the DR single tank wings come with them...mine did, and i'm ok with it for single tank rec diving. I rarely use it anyway.



I'm surprised no one took my troll bait yet

 

[Thalassamania]

I see little or no purpose to having an inflator pull dump, but then I also suggest that those who dislike them take one apart and see how it works before they invent reasons to oppose using said same.

 

[RJP]

...I also suggest that those who dislike them take one apart and see how it works before they invent reasons to oppose using said same.

I have.

Wasn't saying that there's excessive stress on the hose and the connection points if all goes well but rather that if the wire goes, you can pull the hose off a clamp or rip the hose itself, especially if it's older and/or not well-maintained.

Either way, there's no real need for one.

 

[bkotheimer]

Well, I'm the OP and I wasn't trolling (nor am I with this followup post). I'm getting ready to switch to a long hose and I've been weighing the merits of a bungeed backup vs. octo-inflator. My reasoning is that if I were to do the latter, I would want the shoulder dump to facilitate venting during the ascent. But it recently occurred to me that, even with the cable, there might be undue strain on the corrugated hose and the wing.

Yes, yes, I know. There are no drawbacks to the bungeed backup and a million death traps to the octo-inflator. It's been discussed ad infinitum on this board. I'm almost there.

 

[Web Monkey]

Well, I'm the OP and I wasn't trolling (nor am I with this followup post). I'm getting ready to switch to a long hose and I've been weighing the merits of a bungeed backup vs. octo-inflator. My reasoning is that if I were to do the latter, I would want the shoulder dump to facilitate venting during the ascent. But it recently occurred to me that, even with the cable, there might be undue strain on the corrugated hose and the wing.

Yes, yes, I know. There are no drawbacks to the bungeed backup and a million death traps to the octo-inflator. It's been discussed ad infinitum on this board. I'm almost there.

An octo-inflater is at worst an annoyance, and certainly not a death trap.

However a shoulder dump integrated into the inflator hose almost does qualify as a death trap, since it's really easy for a stressed out diver to pull hard enough to break the cable and tear the hose, leaving a BC that won't hold air without some clear thinking and the ability to maintain head-down trim.

I haven't used mine since almost ten years ago, when I ripped the hose off over a wall in Cozumel. The "rings" that make the hose flexible are perfect perforations and rip really easily if dried out, nicked or cracked at all.

Terry

 

[RJP]

I'm getting ready to switch to a long hose and I've been weighing the merits of a bungeed backup vs. octo-inflator. My reasoning is that if I were to do the latter, I would want the shoulder dump to facilitate venting during the ascent.

Let's think this the rest of the way through...

You're going to put the octo-inflator in your mouth...and then pull on it to vent from the shoulder dump?

:shocked2:

 

[Thalassamania]

I have.

...

Either way, there's no real need for one.

Agreed.