Closed isolation valve during dive.

[Hobby]

Outstanding.I enjoy learning such Machiavellian "activities of daily living".Now,I'm off to train fluffy labrador pups to retreive hand grenades!Hey,if it's good enough for the Russians.......
Tip for the day,"Throw bread in the air for the seagulls when under way on your liveaboard.When you have their undivided attention,launch a handfull of alka seltza tabs.(Go to confession when back in port)
Yours,(horribly),Hobby.

[Dr Stevil]

Is that the,AIUI, urban myth about them exploding 'cos of the gas?
I reckon its more likely they'll barf their guts onto the boat first, unless you know otherwise...?
BTW Hobby, Was it you who explained the origin of the phrase "Booby Trap" recently
CHee-az
Steve

[Hobby]

Sorry mate,not me on the booby trap.As for the gulls,it's supposed to be true as they can't expel the gas.Having said that the world was flat once y'know!Regards,Hobby.

[Jay]

I find that, instead of adding helium to my mix, adding smoke from some Amsterdam skunk mellows me out and makes the effects of narcosis almost indiscernable. I recommend about 1/8 oz per 12 litre tank. It works out about the same price as a trimix fill but it makes the surface interval pass so much more enjoyably.

[JohnK]

Following on from Daves question, and this might be a bit numpty but here goes.

My SPG is on my LH tank. If I have to isolate this tank and run just from the RH one will the SPG show pressure remaining in the RH tank given that they are manifolded. Effectively will air from the RH tank flow thru manifold up to isolated LH tank valve then into SPG  

Jeez - hard enough trying to describe what I mean !!!

[Ammers]

Of course it won't. The gauge on the left tank will show you only what is in the left tank.  You are effectively guessing what is in the right tank if you have to isolate. With DIR, you have to question why George and JJ choose particular configuration and consider the environment they are applying it to.  The caves in the UK are small, tight and have very limited visibility. I had to isolate my tanks inside Hurtle pot and I could not see how much gas I had left in my right tank. You really need to have a gauge on both tanks.


(Edited by Ammers at 8:28 pm on Jan. 17, 2003)

[JP]

Anne Marie, surely if you were shut down and couldn't get to the iso'd tank then I have two points.

If it was a blow out that meant you could not reopen after the shut down, there by leaving the SPG redundant

OR

If you couldn't reopen cos the free flow restarted on opening the iso valve  Then I have a question:

who cares how much gas you have left???Its time to go, no questions asked?  Did you feel like you had time to check yur guage?  Time to go..no?

So why have a second SPG?  more fail points and clutter for what benefit?

Just a thought.

[Dr Stevil]

If a problem develops and you need to shut down, and it isn't solved on reopening the valve, then I think it's time to head back up (assuming you want to live long enough to become a boring old git like me)
All in my very humble opinion of course...
Chee-az
Steve (2 tanks & 1 spg)

[Driftwood]

Just remembered this....

Guy was diving twin-12's on the Kintyre last year and had not opened his isolator (or not realised it was shut) before jumping in on his first dive.

Twinset, lots of gas, no need to check the spg right?

Went OOA ascending after half an hour, buddy was too far away or unable to help, they were unable to open the iso....

May they rest in peace.

[Davey Willo]

I'm confused on this one Drifty, why didn't he go to his back up regulator which was I assume being fed from the full cylinder?