anatomy of the GUE Valve Drill

[MATTBIN]

Sorry this isnt meant as a hijack, When I went invert a while ago on for me a new twinset there was a discussion on here about how to shutdown, I stated that I would go for the rh valve (same reasons as you - most likely) and I'm sure I recall one of the DIR guys/instructors saying "go for the isolator", I will see, when I have a moment if I can find it in the archives.

I'm still not sure though that item 11, close and open isolator will tell you if the manifold has gone or not, surely only by closing both pillar valves will you then know, gas can only escape through the manifold whilst you have gas in the tanks, shutting the isolator will tell you nothing about the manifold. It wont stop the gas leaking from it.

Matt

[David]

Garf is a Pandemic..

valve drill well I can say that last night i did a valve drill simlar to garfs discription, well I think it was but this was my first ever atempt at it and I was very pleased with myself if only because I could reach the valves. we chatted about Diving on way to the pool apart from no clue about frog kicking the valves on my new twin set were worring me a little. now I have a least some hope of saving some gas.

David

[Garf]

Originally Posted by MATTBIN

Sorry this isnt meant as a hijack, When I went invert a while ago on for me a new twinset there was a discussion on here about how to shutdown, I stated that I would go for the rh valve (same reasons as you - most likely) and I'm sure I recall one of the DIR guys/instructors saying "go for the isolator", I will see, when I have a moment if I can find it in the archives.

I'm still not sure though that item 11, close and open isolator will tell you if the manifold has gone or not, surely only by closing both pillar valves will you then know, gas can only escape through the manifold whilst you have gas in the tanks, shutting the isolator will tell you nothing about the manifold. It wont stop the gas leaking from it.

Matt

We have already disgnosed that the right post is not the cause of the problem. that leaves the junctions between the manifold and left and right posts, the isolator, and the left post.

If we isolate at this point, we limit the escaping gas if it is either side of the manifold. closing the isolator will keep the gas in either side of the set, whichever side has failed.

The isolator itself we can do nothing about if it has failed.The gas is going to go.

that then leaves us free to diagnose the left post. Remember this is a drill. would I open the isolator immediately after closing it. No. This is a drill to build muscle memory, not to replace the thought process of diagnosing a problem. this is adifferenc ein approach between the nonDIR and DIr approach. the TDI method I taught was all about "SAVE the GAS" and then worry about the cuase later. The GUE approach is completely different, more about diagnosis and understanding. If I can't save the gas it's no biggie anyway. everyone else in the team has enough gas to get them and me to the next gas source.

[Mark Powell]

Originally Posted by Garf

the valve drill in DIR, as with all DIR drills, is not something an individual does, as in a TDI valve drill, it is a team drill.

I have to pick you up on this. A TDI valve drill should still have your team monitoring the diver doing the drill for exactly the same reasons.

GUE don't have the monopoly on diving as a team.

[GLOC]

Originally Posted by Mark Powell

I have to pick you up on this. A TDI valve drill should still have your team monitoring the diver doing the drill for exactly the same reasons.

GUE don't have the monopoly on diving as a team.

I agree with that Mark, but I don't remember when I did my TDI trg that the team is used to diagnose the fault after the initial shutdown has taken place. This maybe what Garf was alluding to.

[Mark Powell]

Originally Posted by GLOC

I agree with that Mark, but I don't remember when I did my TDI trg that the team is used to diagnose the fault after the initial shutdown has taken place. This maybe what Garf was alluding to.

That may well have been what Garf was alluding too but team diagnosis wasn't mentioned in the breakdown of the drill. The quote I objected to said that a DIR shutdown is a team drill whereas a TDI shutdown isn't. It's only that statement I was objecting to.

[Foggy]

Thanks for the post Garf, very informative.

Garf you know me well enough not to take the following the wrong way, but I still have some problems about the logic involved in the drill, and would be genuinely grateful if someone could clarify ....

Originally Posted by Garf

we shut down the right post as that is the most likely to fail. And agreed sometimes you cannot tell where the bubbles are coming from.

But to some extent we are playing the numbers. We know that gas is leaking from somewhere. If we shut down the isolator and it is the isolator that has failed, then the gas is going to continue to leak out and we have gained nothing. We shut down the right post becuase that IS the most likely to fail and if we shut it down we will limit the amount of lost gas. Its down to a difference in how you approach the problem. The "isolate first" school of thought basically involves reserving half the remaining gas. The DIR school of thought is more to do with diagnosing the problem, and closing the isolator first gives us no feedback about the nature of the problem if the bubbles do not stop. If we agree that the failure can be either one of the posts. It's almost certainly not going to be the left post, as that is sitting around your neck not under stress, and a left post failure is usually obvious from the location of the bubbles. that means its likely to be the isolator or the right post. If the isolator has failed you are going to lose all of your gas anyway. So you might as well go for the one that is most likely to have failed, and already start learninig about where the failurer has occurred.

Crystal clear, if the source of the problem isn't known...shut the post most likely to have caused the problem. Now you know if it is the problem, reopen if it isn't, OK...

Originally Posted by Garf

We have already disgnosed that the right post is not the cause of the problem. that leaves the junctions between the manifold and left and right posts, the isolator, and the left post.

With you so far...

Originally Posted by Garf

If we isolate at this point, we limit the escaping gas if it is either side of the manifold. closing the isolator will keep the gas in either side of the set, whichever side has failed.

Whilst this is true, it was also true at step 1. For the same logic you applied in chosing to shut down the RHS first rather than isolate, I think you should shut the LHS post next. Indeed, I think you already know this.....

Originally Posted by Garf

The isolator itself we can do nothing about if it has failed.The gas is going to go.

So why waste time shutting it? If it wasn't the RH post, the left is the only thing you can do anything about so surely this should be shut next?

Originally Posted by Garf

that then leaves us free to diagnose the left post.

Whoa, back up there. You shut the RH post = lets say its not the problem. You've already said that leaves the manifold which you can do nothing about or the LH post - You have already diagnosed this just by shutting the RH post..... or did I miss something??

Originally Posted by Garf

Remember this is a drill. would I open the isolator immediately after closing it. No. This is a drill to build muscle memory, not to replace the thought process of diagnosing a problem.

I know it is a drill, but drills do more than just build muscle memory - they aid in calming a dangerous situation because you just F'n do it - you know its the right thing to do and you do not have to engage the brain. I personally go all weak kneed at the sight of blood, but I have treated some gory first aid incidents by reverting to drill.

Originally Posted by Garf

The GUE approach is completely different, more about diagnosis and understanding. If I can't save the gas it's no biggie anyway. everyone else in the team has enough gas to get them and me to the next gas source.

Now I am confused. If I follow this last piece of logic, why do you use twins with all those extra failure points? If the team has enough gas anyway??

[milldog]

Originally Posted by GLOC

I agree with that Mark, but I don't remember when I did my TDI trg that the team is used to diagnose the fault after the initial shutdown has taken place. This maybe what Garf was alluding to.

I would disagree with this if i was diving with Gary and he had a problem i would assist in diagnostic and remedy if i could, and we carry enough gas to get each other to the next gas switch or surface if need be.

i didnt pass my Trimix course first time because i didnt watch and help my buddy team so it is taught on TDI courses

i don't know anyone who wouldn't do this and they are not all DIR

[Garf]

Originally Posted by Mark Powell

I have to pick you up on this. A TDI valve drill should still have your team monitoring the diver doing the drill for exactly the same reasons.

100% agree with this, my apologies Mark. However, what I was alluding to was this. When I had to go back and redo part of the TDI deco procedures course, I had to go back and do a valve drill. However, in Tech1 we stand or fall on our drills as a team. Whilst there is a team element to TDI training, and perhaps you emphasise it more than other instructors I have met, I do not believe the team element is as rigidly enforced as in GUE training.

However, as for giving the impression that TDI is based on sole skills andnot team orientated, you are correct and I apologise.

[Garf]

Originally Posted by Foggy

Whilst this is true, it was also true at step 1. For the same logic you applied in chosing to shut down the RHS first rather than isolate, I think you should shut the LHS post next. Indeed, I think you already know this.....
So why waste time shutting it? If it wasn't the RH post, the left is the only thing you can do anything about so surely this should be shut next?

You can shut either post and still lose all the gas from that cylinder. Shutting the isolator will stop the gas migrating from one side to the other

Whoa, back up there. You shut the RH post = lets say its not the problem. You've already said that leaves the manifold which you can do nothing about or the LH post - You have already diagnosed this just by shutting the RH post..... or did I miss something??

yup, I said we can do nothing about the isolator. We can certainly do something about the manifold. By closing the isolator we can isolate leaks at the point where the isolator joins the right and left posts. A leak at one of these points will result in the los of all gas from one cylinder, but isolating limits it to one cylinder.

I know it is a drill, but drills do more than just build muscle memory - they aid in calming a dangerous situation because you just F'n do it - you know its the right thing to do and you do not have to engage the brain. I personally go all weak kneed at the sight of blood, but I have treated some gory first aid incidents by reverting to drill.

"just F'n do it" is actually what we are trying to avoid. the DIR approach is to think about what might be wrong and diagnose the problem, rather than leaping in. Other approaches might then take a "OK, now calm down and diagnose the problem", I guess DIR just tries to do that from the first step.

Now I am confused. If I follow this last piece of logic, why do you use twins with all those extra failure points? If the team has enough gas anyway??

Becuase hopefully none of these failures will occur and we get to take advantage of having all that extra gas. It's the same logic as using thirds. Using thirds means a team of 3 divers comes up with a spare twinset of gas between them. How is that any different from us planning to keep enough to get two divers up to the next gas source? Using DIR's principle of minimum has means we always reserve enough gas to get outselves and another diver up to the next gas source, whether that be a gas switch or the surface. That's a calculation that tells us how much gas we need should one diver lose ALL their gas. It's just a gas rule like thirds is, with a little more refinement as it is calculated based on depth.

However, you've just got me thinking, and expect another thread on this subject imminently