Recommended depths/times - Shutdowns!

[Mal Bridgeman]

Originally Posted by Mark Chase

Some schools of thought have the isolator fully open but they also tend to go for the primary reg post first rather than the isolator. Which is cool assuming the fault is on the primary reg and you can reach it OK.

A certain agency with a "worldwide interest in exploring the underwater environment" recommends the isolator be left fully open but that you go for the valve that's leaking, be it left or right .... if you are not sure then go for the right cos that's the most likely. Either way you signal your buddies as soon as you hear the bubbles and they are in place ready to help diagnose and fix the fault within a short period of time anyway

I am pretty sure I read somewhere (though I can't now find the source) that the actual manipulation of any valve must be in under 15 secs .... anyone able to confirm that?

HTH
Mal

[japandiver]

Shutdowns are important, but, to echo Howard, reliably holding stops is a key skill.

Practice holding midwater stops with a visual reference - ie shot and then turn around and hold them without being able to see the shot. This is something that can and should be done at the end of every dive.

Next step - start task loading at a mid-water stop with no reference - deploy your DSMB, flood and clear your mask, remove and replace mask, swap mask.

Once your happy with all of these and your confident that you can reach your valves then spend time at the beginning of dives and at 6m doing shutdowns.

Once you've got the buoyancy control and the flexibility / kit set up valve drills are not a drama. Slow and steady is good, rushed and chaotic is not.

Hugh

PS - next time you're stuck in a traffic jam do some arm stretches - reach round behind your neck rest as far as you can and hold until the traffic moves. It's more productive then getting stressed at the traffic.

[Mark Chase]

Originally Posted by Timbobaggins

Get a Rebreather, then you don't have to worry about all this cr****p

No we have completly new crap for you to worry about



By the by the ONLY freeflow I have ever suffered was on a CCR. I reached back and isolated my gas and in the time it took to turn off the valve the tank was totaly empty. Admitidly it was a 3ltr but I lost 510ltrs of gas in the time it took to shut down an inverted easy access valve from fully open.

ATB

Mark

[James The Badger]

Originally Posted by Rod Abbotson

E
make sure you can do the full drill quickly at max depth were narcosis becomes a factor.

Not my idea of fun, getting the whole team smashed at depth on a crap mix and then start shutting things down.
Personally I would choose lots of a nice gas that removes that problem, or if you have spent all your pocket money on wrist slates and day glow lanyards, just do the drills at 6m

[Mark Chase]

Originally Posted by Mal Bridgeman

A certain agency with a "worldwide interest in exploring the underwater environment" recommends the isolator be left fully open but that you go for the valve that's leaking, be it left or right .... if you are not sure then go for the right cos that's the most likely. Either way you signal your buddies as soon as you hear the bubbles and they are in place ready to help diagnose and fix the fault within a short period of time anyway

I am pretty sure I read somewhere (though I can't now find the source) that the actual manipulation of any valve must be in under 15 secs .... anyone able to confirm that?

HTH
Mal

They say because if the valve is not fully open you might turn it the wrong way to close it????????


Obviously the course was designed for Americans


ATB

Mark

[SoggyFox]

Originally Posted by Mark Chase

Admitidly it was a 3ltr but I lost 510ltrs of gas in the time it took to shut down an inverted easy access valve from fully open.

you run your valves fully open?

i usually have mine 3 hand turns (more like half turns open), then its second or 2 at most to shut them off.

[Mark Powell]

TDI standards state that a shutdown drill should be conducted no deeper than 30m.

[Mark Powell]

Originally Posted by Mark Chase

They say because if the valve is not fully open you might turn it the wrong way to close it????????


Obviously the course was designed for Americans


ATB

Mark

I've seen plenty of people in this country get confused about this when under stress.

[SoggyFox]

Originally Posted by Mark Powell

I've seen plenty of people in this country get confused about this when under stress.

are these the same people who walk into doors, with the sign "PULL" on them.

[nigelH]

Originally Posted by Mark Powell

I've seen plenty of people in this country get confused about this when under stress.

They clearly didn't have Meccano as children.
That puts it in at brain stem level.
Your fingers know do-up from undo reaching backwards, upside down in a hole pointing back towards you.


Of course it does mean that a left hand thread causes much angst and anguish. I had a very standard looking 15mm LHT nut and bolt on my desk at one engineering company and I've seen grown men just sit and wind it in and out for ages with a look of total pain on their faces. They knew what it was but something inside just wouldn't quite believe.