Pull Dumps — lose them

[gcarter]

Sorry to pull this thread back to its origins, but I realized some time back that a pull dump is a LESS likely configuration to disconnect where the inflator hose attaches to the elbow. . .

There is, after all, a stainless cable that attaches at both the dump valve and the elbow (and that cable is designed to be shorter than the inflator hose). I have no idea what the breaking strength of that cable might be, but I'm certain it is more than could possibly be exerted (even in a full scale panic)

The constant use of a pull dump places stress on the joint where the flange is welded/glued to the bladder. Pulling on a relatively unbreakable steel cable makes it more likely that you will eventually tear out or break the flange it is all attached to. You are simply moving the weak point.

Much better to never even view pulling on the hose as a thing to do.

 

[gcarter]

Power inflator mount to bc repair needed

Note post #6

 

[Bob DBF]

I have never seen any value in the pull dump. When I first started diving I found it hard to control anyway. The valve at the end of the hose gave me better control.

The value in a pull dump is when you are breathing on your Air2 and need to dump air. Other than on the poodle jacket with an Air2 clone, I have never had a pull dump as standard equipment on any BC I have had.

I agree there is more control with the valve at the end of the hose.



Bob

 

[Coztick]

My first bc (Zeagle) had a pull dump that I was aware of but preferred not to use as I saw it as unnecessary.
I've since gone to a harness and wing that has no venting on the top, inflator on the left,bottom and in side of the wing and a butt dump/OPV valve on the right, bottom, in side.

I'm pretty sure that there is no need to hold the inflator overhead to descend as all I do is lay back on the wing and it vents just fine from the bottom through either vent. And yes, I'm properly weighted.

All this talk of stuck power inflators has got me thinking I should reserve its use for surface and emergency.
I will connect and test it but I'm thinking I may be well served by making oral inflation a skill to master.
In the event of a stuck inflator, I don't think trying to vent through a pull dump would be as effective as venting through a butt dump and finning down to maintain depth.

 

[grf88]

In the event of a stuck inflator, I don't think trying to vent through a pull dump would be as effective as venting through a butt dump and finning down to maintain depth.

The problem with that is it leaves you only one hand to disconnect the inflator hose. I find it better to hold the inflator high and dump from there while at the same time disconnecting the inflator hose allowing you to use both hands to disconnect. If you are holding the inflator higher than the wing or BC most air will take the easier path straight out instead of going into the bladder. I would suggest you try it in the pool or shallow to see if it works for you with your gear.

 

[AdivingBel]

All this talk of stuck power inflators has got me thinking I should reserve its use for surface and emergency. I will connect and test it but I'm thinking I may be well served by making oral inflation a skill to master.

Maybe if I personally had repeated issues with a power inflator I would consider abandoning it's use (would probably just get a more reliable power inflator), but I wouldn't do it based on SB hearsay. Not to demean SB expertise, but we're talking about something that's used thousands of times per failure (and more if properly maintained) and you can learn to deal with the odd issue. It's awfully convenient to press a button to bump a little air when you drop in to your desired depth. That said, nothing wrong with mastering a new skill. All IMHO, YMMV.

 

[John Bantin]

And the weight of the gas used during the dive, which these days can be substantially more than that contained in the smaller cylinders of old.

About 2.5kg for a regular 80.

 

[The Chairman]

How come back before there were BC’s nobody ever seemed to have a problem?

What are you talking about? That was always an incredible problem. There was never any rest on the surface: you had to keep kicking and kicking and kicking. Snorkels were important back then because of this. Now you can inflate your bc and float on your back. Who needs a snorkel anymore?

Surely, the primary point of a Buoyancy Compensator is to compensate for the loss of buoyancy caused as the suit is reduced in volume due to the pressure of depth?

That wasn't the original intent. Some of the first ones I remember had a CO cartridge in them. They were for safety after the dive.

 

[BRT]

What are you talking about? That was always an incredible problem. There was never any rest on the surface: you had to keep kicking and kicking and kicking. Snorkels were important back then because of this. Now you can inflate your bc and float on your back. Who needs a snorkel anymore?

That wasn't the original intent. Some of the first ones I remember had a CO cartridge in them. They were for safety after the dive.

This is so true. When there is stress on the surface there is nothing like blowing up your BCD and getting your head way above the water.

 

[rsingler]

Maybe if I personally had repeated issues with a power inflator I would consider abandoning it's use (would probably just get a more reliable power inflator), but I wouldn't do it based on SB hearsay. Not to demean SB expertise, but we're talking about something that's used thousands of times per failure (and more if properly maintained) and you can learn to deal with the odd issue. It's awfully convenient to press a button to bump a little air when you drop in to your desired depth. That said, nothing wrong with mastering a new skill. All IMHO, YMMV.

+1!!!
Two extremely accurate observations, either one of which would markedly decrease the incidence of a stuck inflator, and all the anguish we've been sharing:
1) "would probably just get a more reliable power inflator"
2) "more if properly maintained"

Yep!
Pay $200 for an Atomic titanium inflator, and ignore it like so many divers do,
or regularly service your inflator.
Or replace it every year or two if it's one of the $17 k-valves.