Is a BOW fast enough to save a life?

PCDiver

Good one Stuart. Have some green.

But I saw a perfect rebreather once ... on TV. I believe it was James Bond who used.

Ben Field

Hi Peter,

I'm not going to get excited over how someone uses their ADV but I do have a couple of questions...

How does having your ADV off help with your 1-4 list?
(I can understand No.2 even if I point out that it shouldn't be leaking I realise it might start to leak on a dive!)
I don't see how it helps the other 3 at all?

I ask as other than shutting my dil off at the tank I can't disable my ADV and I have no issues with those 3 (or 4) points, in fact for 1 and 3 I would prefer to have my ADV active!

(I'll conceed it may be an operation issue particular to your unit which I'm not trained on only familiar with)

regards,
BEN

__________________

Beware Fridge Suck

Dave Sutton

Nonsense. Not in any sort of quality kit that was well maintained before the trip. The regulator mechanism is internal to the rig.... how much salt gets in there? If you have sufficient salty-skudge in your rig's innards to worry about your ADV, you've already had more trouble than a freeflowing ADV...... you're recovering from the aftermath of a loop flood (or from really poor chronic maintenance deficiency.... meaning over months, not days).

In any event, there's more than one way to skin the cat. Until you need to do a quick flush without using your hands, your way will work. Mine works with both hands occupied and I've never had an ADV freeflow, while I have quite gladly gone open-loop on many occasions (in some small way on 100% of my dives, for little utility reasons like fine bouyancy control and PP02 adjustment), so what works works. And I'd *never* consider a rig that has an ADV that freeflows when I roll to one side to be "well designed"... it's a design deficiency. If you accept that and have developed a work around method.... good for ya. Just don't believe for a moment that you're doing anything other than working around a flaw. That's not bad... we do it all the time in many machines we use. Just recognize it's truth. If I had to dive a YBOD (*Really* unlikely, but.. *if*...), I'd design and make an ADV that *worked*. It would not be in the counterlung.... it would be where it belongs, in the head (actually exterior to the head on a YBOD, but functionally it would be "at the head". Shit, maybe I'll make one anyhow for someone to try.

Actually I'd just wait for the combined BOV/ADV prototype that will be here in September.... . That'll cure the argument.


Dave

trob09

"The more I see people argue about religion, the happier I am to be agnostic"

- someone wiser than I

PCDiver

1. detection of loss of loop volume - any loss of gas will be noticed by not being able to take full breaths. So you add manually. Adding manually is a step that is more noticable to the diver than the ADV kicking in, especially if it happens too often.

3. just my way of doing it. I hate an ADV during long deco hangs. They kick in when not needed. The earlier I close it the better.

4. better diluent control - I'm just more aware of gas consumption with the ADV closed, because every time I have to manually add, I makes me think about where the gas went. Have I been breathing out via my nose, depth changes, clearing my mask, ....

Dave Sutton

Cannot really argue with that. Just an observation though, the CIS was the first rig with an ADV "off" mode, and it was generally reserved only for deco, as you suggest, or for a failure of the ADV. On the bottom it was generally left open...

All of your other statements are points well taken, although I respectfully disagree with your conclusions. You can tell with ease when an ADV is triggered at depth, no matter how easy it cracks, and it ought to trigger the same question-set in the brain as what you suggest is true when you manually add dil. In any event, the differences are *very* slight and probably have no practical difference in typical situations. With that said, I'm still going to have an open-loop mode available hands-free whenever I can, which is most of the time.


Best,

Dave

nigelh

Careful. That's the cry of the twinset wannabee We have moved beyond that. They recite it like it was some holy matra but why do you want an uncluttered chest? That's the one place you can reach fast so that's where you want the important things. You'll be putting the valves at the top next.

Back to ADVs... I have one of the old Bob ones. I liked it so much I bought his BOV. I have it set very slack so I really don't feel minimum loop tighten the breathing as some people tell me I should but I still seem to stay near enough there. It's not based on an expensive reg so I doubt it's really high quality breathe but it's got me out of trouble once. I have an Apeks flowstop on it but that's really only there for disaster recovery and so I can get a negative test without draining it all down. Once I have both hands on the camera my ADV and my nose become my fine trim control.

I guess if I'm ever forced into oxygen topup mode I'd better shut it off but that's a bit alpinest for me.

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nigelh

Drmike

imo spot on - especially the last part!


i close mine on ascent to aid keeping min loop/ppo2 levels otherwise its left open.

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Cave diving is a sport
Wreck diving is a sport
Diving in general is a sport

'Rebreather diving' is not a sport
its the delusional obsession with a highly dangerous and often inappropriate piece of equipment

Gilles

This is what I have always understood to be the purpose of the S/O valve.

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Gilles
http://www.dirrebreather.com

ScubaDadMiami

Where I will be at a constant depth, I close the ADV so that I can maintain minimum loop volume without the ADV adding gas when I don't want it to. When I will be varying my depth throughout the dive, such as in a cave, I leave it open since there will be too much fiddling around with it otherwise.

You see, you're all right no matter which side you are on here.

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Howard Packer
IANTD CCR Instructor
Miami Beach, Florida
CCRDiveTraining.com