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On 7/25/98 6:26, Jim Cobb, cobber@ci*.co* posted:
>Jammer I am thinking in terms of deco diving. IMHO a H or Y valve does
>not turn a single into a true redundant system suitable for decompression
>diving. The problem is that you have 2 knobs but they are still feeding
>into essentially one valve. If you have a problem with a valve, busting a
>knob off for example, you cannot isolate your gas. With doubles you close
>the iso valve and you still have enough gas if you are doing thirds. With
>an H valve you are shit out of luck. So, don't do deco with a single, if
>you do you are fooling yourself.
I agree that H valves aren't going to get it- going more on faith there,
I've spoken with a DIR diver who tried them, here, for single tank dives.
He said that one of them is backwards, and it doesn't mimic a dual tank
system. I'm particularly interested in his opinion., and I've bcc'd him
with this.
I've seen a new Y valve though, that looks like it would be OK.
No, I agree that Y valves don't provide true redundancy, but then neither
do duals.
Both systems provide a single source of gas that can be accessed from
either post, while isolating a failure that occurs on one of the post.
There's a single point that will compromise both systems, and it's been
my understanding (someone yell if I'm wrong) that a failure in the
isolation valve could compromise doubles, while a failure of the main
stem O ring could compromise a Y valve.
I further understood, (and need to be yelled at if it's wrong) that these
failures were statistically insignifigant, that the rates of failure at
these points were acceptable risks, and far smaller than the failure
rates of single systems.
I haven't bought a set of Y valves yet, but I AM looking for a way to
clean up single tank diving, and get rid of that FUCKING 30.
Had one of the best dives of my career a couple months ago- I re-rigged
my octo, and left my 30 on the boat.
Allright, I'm listening, everybody begin yelling.
Ready, ....
YELL!
"C'mon, you sons of bitches, you want to live forever?"
-First Sergeant Dan Daley
"Who wants to live forever?"
-Freddie Mercury
"I swear, I'm going to live forever"
-Jon Bon Jovi
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