Right post first?

[grazie42]

Someone who´s done Dir-f (and passed) told me that the valve-shutdown procedure on doubles is to start with the right post.

If that´s correct it seems as if you´re gambling your gas-reserve on "guessing right" instead of ensuring that you save half your gas and then try to solve the problem, knowing that you still have gas left. That seems like a bad idea to me, I know from experience that if the problem is in the 1st stage (as opposed to a freeflowing reg) it´s very hard to determine which one is the one with the problem...

[JohnKendall]

Quote: (Originally Posted by grazie42)

Someone who´s done Dir-f (and passed) told me that the valve-shutdown procedure on doubles is to start with the right post.

If that´s correct it seems as if you´re gambling your gas-reserve on "guessing right" instead of ensuring that you save half your gas and then try to solve the problem, knowing that you still have gas left. That seems like a bad idea to me, I know from experience that if the problem is in the 1st stage (as opposed to a freeflowing reg) it´s very hard to determine which one is the one with the problem...

A couple of things.

The Valve Drill always starts with the Right post. This doesn't mean that in the event of a problem you always go for the right post regardless. The reason we have a standardised Valve drill is so that when you are practicing, both you and your team have a framework to work to, and know what is going on.

In a real failure, you go for the post where you think the issue is. You then breath down/de-pressurise the reg. If the bubbles stop, you got it right, if they don't you go for the isolator and involve your team.

If you just blindly go for the isolator you've not gained anymore feedback, so to get any feedback you've now got to shut another valve.

Most of the time you will get the correct valve on your first go, so in these situations you've saved more gas. If you don't, or if it's a problem that can't be solved by shutting down a reg (Neck Oring, Manifold failure etc) then you need your team anyway, and that's going to take a little more time, so you now shutdown your isolator.

In any situation you should be signalling your team for assistance as soon as you realise you have an issue.

HTH
John

[Joe Hesketh]

Quote: (Originally Posted by Mark Chase)

Strange when I read Clare's report on the changes it read that thats exactly why it was changed.

The valve drill was changed because it more closely follows the sequence employed (as taught by GUE) on a real shut down (which ultimately is the point of the drill), i.e. it is unrealistic to ever shut off the left post whilst breathing it and have to switch to the long hose.

Reducing the likelihood of accidentally turning off all your gas or worrying about getting back to the long hose might be added benefits but AIUI not the point of the change.

[Clare Gledhill]

Quote: (Originally Posted by Mark Chase)

Strange when I read Clare's report on the changes it read that thats exactly why it was changed.

Not in the slightest Mark - although I may certainly have said that one of the advantages of the drill is that a diver is no longer running the risk of closing all his valves at the same time - which can happen when our brain takes a walk for a while....

The Valve drill was changed because breathing your backup whilst shutting down your left post just would not happen in real life - and led to all sorts of "do I unclip my primary first" questions which made the Training Council realise that a better way of practicing should be found. Whilst it is a "drill" it's nice that now we practice to purge our left post if we have shut it off - exactly as we would do in a real situation.

Quote:

The PLB thread is a case in point. We have Tec2 level GUE divers saying "we don't do up lines if we cant drift deco we don't dive" and JJ puting a section in his traiing manual about doing up lines?? Most odd

Dunno if this is aimed at me after our chat in the pub - but Bob and I have agreed to come out on the Delta boat and give it a go remember....

Thing is if other Tech 2 divers say that they don't want to do station deco that is their choice. Their reluctance has less to do with whether it is DIR or not and more that they simply can't be bothered

I've certainly never seen or heard any suggestion that DIR divers can't carry PLBs - not from the agency anyway. I always carry a spare mask, a spare spool, spare double ender, and quite often a spare SMB as well. Seems a bit silly not to - I know my team can get me out if I lose my mask but why go to all that hassle when I can carry a spare. If my team mate loses one - well he can have my spare if he doesn't have one of his own.

It's too easy to confuse statements on the internet by people who support the DIR system of diving with statements about the system itself.

When it comes to moving stages around - good lord that poor guy who dropped on on his training course - will he ever live it down? Let's be charitable and reasonable shall we and remind ourselves that if you can't make mistakes on a training course when can you?

[Mark Chase]

Quote: (Originally Posted by Clare Gledhill)

Not in the slightest Mark - although I may certainly have said that one of the advantages of the drill is that a diver is no longer running the risk of closing all his valves at the same time - which can happen when our brain takes a walk for a while....

The Valve drill was changed because breathing your backup whilst shutting down your left post just would not happen in real life - and led to all sorts of "do I unclip my primary first" questions which made the Training Council realise that a better way of practicing should be found. Whilst it is a "drill" it's nice that now we practice to purge our left post if we have shut it off - exactly as we would do in a real situation.



Dunno if this is aimed at me after our chat in the pub - but Bob and I have agreed to come out on the Delta boat and give it a go remember....

Thing is if other Tech 2 divers say that they don't want to do station deco that is their choice. Their reluctance has less to do with whether it is DIR or not and more that they simply can't be bothered

I've certainly never seen or heard any suggestion that DIR divers can't carry PLBs - not from the agency anyway. I always carry a spare mask, a spare spool, spare double ender, and quite often a spare SMB as well. Seems a bit silly not to - I know my team can get me out if I lose my mask but why go to all that hassle when I can carry a spare. If my team mate loses one - well he can have my spare if he doesn't have one of his own.

It's too easy to confuse statements on the internet by people who support the DIR system of diving with statements about the system itself.

When it comes to moving stages around - good lord that poor guy who dropped on on his training course - will he ever live it down? Let's be charitable and reasonable shall we and remind ourselves that if you can't make mistakes on a training course when can you?

Clare i am not having a go at anyone and I am not having a go at DIR or its standards. Unlike some, I don't have to degrade my posts with personal attacks because my arguments are so week either

I think its useful to see how information written down by respected DIR divers on here is perceived by newcomers. As an example, I get a strong impression from divers like your self, Bob and others, from previous posts, that up-lines and drift stations are not DIR.

I get a strong impression from most of the DIR divers i have met and dived with that they generally use a single depth and bottom timer and carry little or nothing in the way of back up equipment ie back up red SMB back up mask back up cutting devices.

Whilst i am well aware of DIR divers who take steps which i think are perfectly justifiable, like carrying yellow emergency SMBs and carrying large wreck reels for SMB usage, I would actually prefer to see more specific guidance or actual standards in these areas.

I answered this post on the basis of, Its a great achievement to have developed this system but.....

And this is exactly the way I feel. In its present guise its an amazing achievement but Id like to see more standards designed for deep wreck OW diving. (coz thats what i do). I am also more than aware that pedantic sods like me are the very people who would have delayed the standards in the first place with loads of arguments.

I cant help it its in my nature.

Andyp said to me the other day Christ Chasey is there ANYTHING left on your CCR thats original. And frankly apart from a scrubber can, gas manifold & loop hoses I have redesigned, rebuilt or replaced every thing in the search for the ultimate tool for the job. I have realized this is half the fun of it for me.

ATB

Mark Chase

[canucksubmariner]

Quote: (Originally Posted by JohnKendall)

A couple of things.

The Valve Drill always starts with the Right post. This doesn't mean that in the event of a problem you always go for the right post regardless. The reason we have a standardised Valve drill is so that when you are practicing, both you and your team have a framework to work to, and know what is going on.

In a real failure, you go for the post where you think the issue is. You then breath down/de-pressurise the reg. If the bubbles stop, you got it right, if they don't you go for the isolator and involve your team.

If you just blindly go for the isolator you've not gained anymore feedback, so to get any feedback you've now got to shut another valve.

Most of the time you will get the correct valve on your first go, so in these situations you've saved more gas. If you don't, or if it's a problem that can't be solved by shutting down a reg (Neck Oring, Manifold failure etc) then you need your team anyway, and that's going to take a little more time, so you now shutdown your isolator.

In any situation you should be signalling your team for assistance as soon as you realise you have an issue.

HTH
John

In a real emergency people do what they have trained and practiced. That means that judgement will not overcome repetitive training, thus regardless of the severity of the emergency they will shut the right post first. Gas is life underwater and I for one am not taking the chance to lose anymore than I have to.
Anyway the argument is moot to a skilled and thinking diver, a divers should be able to manipulate the center valve with either hand while also isolating a post with the other. It isn't even as hard as walking and chewing gum.

[rjack]

If you subscribe to the concept that the right reg is more likely to fail than a post, it makes more sense.

Whether anyone has any hard data to support regs failing more than posts, I doubt.

Richard

[canucksubmariner]

Quote: (Originally Posted by rjack)

If you subscribe to the concept that the right reg is more likely to fail than a post, it makes more sense.

Whether anyone has any hard data to support regs failing more than posts, I doubt.

Richard

Because the right post is the post you breath off and inflate the wing from it seems the logic is it gets more cycles, thus is more likely to fail. I personally don't really agree.

[grazie42]

Quote: (Originally Posted by rjack)

If you subscribe to the concept that the right reg is more likely to fail than a post, it makes more sense.

Whether anyone has any hard data to support regs failing more than posts, I doubt.

Richard

But if your gas-plan is ok (it should be as you´re DIR), you´d never need more than half your backgas to get out anyway...the "extra" gas you may save by closing the "right" valve first has no real survival value to you, while losing more than half could potentially get you killed...

Let´s say you dive 1/3s (the least conservative) and something happens just as you turn the dive. You can either:
1. Close your isolation valve, have a worst case scenario of ½ your BG left (=1/3) which is still enough for you to get yourself out.
or
2. Close whichever post you´re guessing has the problem, have a worst case scenario where you´re basically OOG.

Am I missing something?

[Mark Chase]

Quote: (Originally Posted by grazie42)

But if your gas-plan is ok (it should be as you´re DIR), you´d never need more than half your backgas to get out anyway...the "extra" gas you may save by closing the "right" valve first has no real survival value to you, while losing more than half could potentially get you killed...

Let´s say you dive 1/3s (the least conservative) and something happens just as you turn the dive. You can either:
1. Close your isolation valve, have a worst case scenario of ½ your BG left (=1/3) which is still enough for you to get yourself out.
or
2. Close whichever post you´re guessing has the problem, have a worst case scenario where you´re basically OOG.

I might have this wrong so bear with me

As i understand thirds its a third of the gas required to get you to the farthest point from the next available gas source and two thirds to get you and your buddy back from there to the next gas source.

On an OW dive if your next available gas source is 21m on 50% you could theoretically run your gas supply down to a few mins of gas needed to get you and said buddy from 60 to 21m?

At that point (yes I know its massively unlikely) a free flow could empty back gas before you got it sorted out.

QED the fastest way of saving gas is the best way.

So the argument is, is going for the primary reg post the fastest way to guarantee some gas reserves?

Obviously TDI we are taught to isolate the center valve first to guarantee 50% of remaining gas.

Just for "Comedic value" :D I used to do the isolator and the primary reg post at the same time. Isolator was only two turns open so took a second or so, primary took how ever long it took (I had good days and bad days) but significantly longer than the isolator.

ATB

Mark Chase