Needed for Cavern??

[PfcAJ]

I doubt you could rotate a burst disk with a ceiling under pressure. Ask the guy I shot a burst disk at when I tried to "rotate" the burst disk out of tank with a wrench that still had air in the tank. I thought to myself seconds before I did something really really stupid. Man this think is friggin tight in here. I gotta get a bigger ratchet. Never occured to me that I forgot to drain the tank.

But, one could burst, one could shear off.

It happened to a friend of mine.

 

[Superlyte27]

Except for the part that if you really lose a tank, half of your gas is gone right when your heart rate is going to be at its highest. Plus, you're back to the same old "which reg do I donate" thing.

Aren't you a cave diver?
If you lose the right tank, breathe off the left regulator. If you lose the left tank, breathe off the right regulator. You're not going to donate anything. You had the failure.

If you dive 1/3 of your air in, and at your max penetration you lose half of your remaining air, how much air do you have left?

1/3 of your air used, leaves 2/3's exit gas. Then tank loses a burst disk (about the quickest loss of gas I know of) and you lose one tank. If you are diving independant doubles how much gas do you have left? 1/3. Which if flow is at your back, should get you out.

Now, you are excited, a little freaked, and a burst disk has really screwed up vis. Is 1/3 enough air to get you back out? That's why alot of people dive 1/3 +

If you are diving isolator manifold, how fast can you shut a manifold?

 

[PfcAJ]

I am a cave diver.

Thats a nice hypothesis, but I'm not one for putting all my eggs in one basket, if I can help it.

Lose a reg, lose half you gas, you might have enough to get out in the other tank. Wanna try it? Lose a reg on manifolded doubles, you certainly have enough gas to get out (provided you can actually close your valves).

When you lose that reg, two things are going to happen. Your heart rate is going to go up, and bubbles are going to be EVERYWHERE. The pucker factor is going to be pretty high, I guarantee it. You better hope you are on top of your game when that happens.

Knowing this, I have my gear configured in a manner that gives me access to the MOST gas after the MOST common failure.

I can shut down my valves in a matter of seconds (I practice it), can you? If not...

With SM, you're switching regs. Are both on an appropriate hose for donation? Which one? Is this a good idea for someone who is new at cave diving? I think the answer is pretty clear here.

 

[Superlyte27]

We're getting way off topic, but a few points.

I'll take a reg failure before a burst disk any day.
I've seen countless reg failures over the 13 years i've been cave diving (none of them mine). None of them emptied as quickly as the burst disk failure I saw two weeks ago.
I can absolutely reach and shut my valves. If not, you shouldn't be cave diving. Essentially you have no redundancy on a manifold system.
It's the uncommon failure that I fear, not the MOST common failure. I plan for the worse case scenario, not the best case one.
And one more time, quite honestly... If I lose a burst disk, I could give a rats a$$ about whether I can donate my long hose or not. LOL.

If you're new at cave diving, and your instructor didn't lay out everything we just discussed. Get a new instructor he's failing you. Everything I just said is elementary.

 

[Superlyte27]

It happened to a friend of mine.

What's his name. I live in Orlando, perhaps I know him.

 

[PfcAJ]

We're getting way off topic, but a few points.

I'll take a reg failure before a burst disk any day.
I've seen countless reg failures over the 13 years i've been cave diving (none of them mine). None of them emptied as quickly as the burst disk failure I saw two weeks ago.
I can absolutely reach and shut my valves. If not, you shouldn't be cave diving. Essentially you have no redundancy on a manifold system.
It's the uncommon failure that I fear, not the MOST common failure. I plan for the worse case scenario, not the best case one.
And one more time, quite honestly... If I lose a burst disk, I could give a rats a$$ about whether I can donate my long hose or not. LOL.

If you're new at cave diving, and your instructor didn't lay out everything we just discussed. Get a new instructor he's failing you. Everything I just said is elementary.

PM sent about the dude who told me that.

A burst disk failure IS mitigated by the isolator. So with doubles vs sm, you have equal amounts of gas available if a burst disk/ tank oring goes, but you have MORE available if a reg goes (which happens often). I'll stick with more gas most of the time.

Seems cut and dry to me. Now, if you really honestly need SM and you are an experienced cave diver, then we can reach a middle ground.

 

[The Chairman]

Hey, I live in Winter Park. It seems like we have this entire thread out of the CFL area.

 

[Superlyte27]

I'm not sure I understand your argument. Ok, I got your argument. Planning on a reg failure, you still have whatever available gas you would have, after you closed a valve, in both tanks. Vs. in independant doubles, you really only have whatever you save in the one good tank.
I'm not saying sidemount for everyone. I'm saying I want to switch to sidemount. For several reasons.

I want to see the Crystal Caves of Abaco one day
I'm fat and old and sick of lugging doubles around
I like the idea of completely independant systems
It looks cooler?

 

[Superlyte27]

Yeah, I knew that Netdoc.
I'm going to bed. You guys have fun,
Netdoc and PfcAJ let me know when you guys are taking me diving.

 

[ianr33]

Lose a reg, lose half you gas, you might have enough to get out in the other tank. Wanna try it? .

Surely you mean "Lose a reg and the buddy team exits uneventfully with plenty of gas to spare?

Or do you dive solo?