When to Use Dump Valve

[Bob DBF]

I use the rear dump when horizontal or head down which is the vast majority of the time. I don't have a pull dump on this rig, however I used it frequently on my last rig.

I second this. Anyone that has serviced pull dump inflators can vouch for their fragility. The worst I have seen is the aqualung version.

I've used and serviced pull dump inflators, and don't find them particularly fragile, but are made of plastic. Misuse makes anything fragile.

IMHO the pull dump inflator mechanism is for emergency only. For standard venting always use a dump valve or deflate button.

The ScubaPro BC manual makes no reference to the pull dump being for emergency use only. In addition it is the first description on how to deflate the BC given in the manual. It also tells the user that pulling on the dump harder will not open the valve more once fully open.



Bob

 

[Dubious]

I just wanted to thank everyone for their replies. I did not expect so many responses. I am glad I found this board.

 

[Dubious]

My wife and I did our first post certification dives in the same quarry we did our open water dives this past Sunday. First dive was following the shop manager. Second dive my wife and I worked on skills.

Anyways, before the dive, I practiced reaching for the dump valve out of water. After some time I felt I had it. My mistake was I did not practice in my 5mm gloves. I had a very hard time locating the string for the valve with the gloves on. Oh well, another skill to work on.

 

[tbone1004]

@Dubious good for you for trying at the surface! One of these days I need to make a video on how to pull them properly which makes finding them with thick gloves easy.
In short, you reach back and found the dump assembly itself which is pretty easy to find. From there you close your thumb and index finger to grab the line as close to the dump body as you can. Again, that should be pretty easy considering it's in the middle of the dump. Since you have it close to the body, you bring the tips of your thumb and index finger in, essentially collapsing the circle that you created in the first place. This pulls the line while pushing the body with your knuckles. This gives you the most control, but also easy to find in thick gloves

 

[KenGordon]

“What’s a kidney dump?” Under water they can’t see you cry...

This subject is close to my heart.

A lot of issues are related to divers being obsessed by the inflator hose. Not being able or comfortable with the kidney dump leads to not being comfortable being in flat trim. Descending feet first dumping from the inflator hose leads to off balance divers, falling backwards due to the heavy cylinder and then flailing about trying to get their feet behind them. Lifting an arm to operate the dump can leave all the excess drysuit gas in that arm so they are unable to sink.

Using the inflator hose all the time is lazy and ineffective. Not being able to operate all the controls on your kit is a terrible place to be.

Sadly new divers like to stick with what works. They are overwhelmed and until comfortable find it difficult to find brain space to consider new things, like reaching round and behind for a dump. If the jacket is fully inflated and they are in a suit, have gloves etc they can find that hard. So the comfort zone becomes being a sea horse, holding a hose all the time. From their point of view it works, up and down buttons to hand, slightly negative the whole time, fine adjustment via finning.

So, OP, just say no to the man outside the school gates holding up an inflator hose. Use the shoulder dump in preference if upright, and then be flat and use the hip dump in general.

 

[KenGordon]

I also concentrate on having my students develop their "muscle memory" with the corrugated hose to deflate, and only introduce other options down the road. My main concern with introducing other options too soon is that the next BCD they use may not have that option.

Not all BCs have a corrugated/inflator hose dump button. I think all that do also have a hip or kidney dump, although the side varies.

 

[AJ]

@Dubious good for you for trying at the surface! One of these days I need to make a video on how to pull them properly which makes finding them with thick gloves easy.

What works for me is a stiff peace of rope about 2 inches/5 cm's. Two knots in it and I have no trouble finding the dump valve, even with very thick gloves. Normal rope deliverd with the wing does not work for me.

 

[rongoodman]

What works for me is a stiff peace of rope about 2 inches/5 cm's. Two knots in it and I have no trouble finding the dump valve, even with very thick gloves. Normal rope deliverd with the wing does not work for me.

Deep Sea Supply made a replacement OPV with thicker cord. I have several on various wings. When I quit diving I'll sell them here and make a fortune!

 

[BlueTrin]

My wife and I did our first post certification dives in the same quarry we did our open water dives this past Sunday. First dive was following the shop manager. Second dive my wife and I worked on skills.

Anyways, before the dive, I practiced reaching for the dump valve out of water. After some time I felt I had it. My mistake was I did not practice in my 5mm gloves. I had a very hard time locating the string for the valve with the gloves on. Oh well, another skill to work on.

If you want a fool proof technique to find the rope to dump.

Grab first the valve itself, then rotate your index around the valve, the rope will get caught around your index.

When this happens push gently backwards and upwards to dump.

If you want you can tie some small knots on the dump valve rope to help gripping your gloves. Some people put a bigger plastic thing at the end of the rope although some agencies will frown upon this.

This video demonstrates better than I can explain:

 

[happy-diver]

Now that's a fat string, look it even stands up by itself

Make your own fat string a couple of knots find the dump and pull it nothing else to think about