Roll Off!

[Scubastud16]

then you should have some kind of redunant lift. So either a drysuit or dual bladder wing.

While you should, there are many that do not.

[TonyDCaver]

then you should have some kind of redunant lift. So either a drysuit or dual bladder wing.

Touche.

[atedeschi]

You dont have to go out and buy a dual bladder you can find a cheap used single bladder and just sandwhich them together. But you should def have something for backup lift and a liftbag does not cut it in my book, def not in a cave.

[TonyDCaver]

You dont have to go out and buy a dual bladder you can find a cheap used single bladder and just sandwhich them together. But you should def have something for backup lift and a liftbag does not cut it in my book, def not in a cave.

I start diving dry sometime next week. Crap we have completely derailed this thread.

As far as valve drills go, I completely agree.

[cavemark]

The comment about the isolator half open/closed seems like a good idea, how many do this and what are the cons? ...also, at times just removing the isolator seems like a good idea as well but that discussion has been beat to death and it seems like a push to me.

The con I see is the possibility that in a real situation you may open instead of closing the isolator and waste valuable time until you realize the mistake. Unless you practice your valve drills single handed (I just realized that I need to start doing that) and you have to isolate with your non-dominant hand, it would be very easy to open instead of close. I feel more comfortable with the valves fully turned.

My first day of cavern I was told to open the valves fully, unlike the way taught in OW class where you open all the way and then close a little. That way you know if you have been making contact sufficient to turn a valve.

Mark

[atedeschi]

The con I see is the possibility that in a real situation you may open instead of closing the isolator and waste valuable time until you realize the mistake. Unless you practice your valve drills single handed (I just realized that I need to start doing that) and you have to isolate with your non-dominant hand, it would be very easy to open instead of close. I feel more comfortable with the valves fully turned.

My first day of cavern I was told to open the valves fully, unlike the way taught in OW class where you open all the way and then close a little. That way you know if you have been making contact sufficient to turn a valve.

Mark

But if you only crack the isolator about 3/4 of a turn, you know when you go to close it if it takes more then that then you are going the wrong way. I also do not like to open my any valves all the way untill the stop and leave them there, just in case the same up. I can't tell you how many time when filling tanks that someones isolator was stuck up because they leave it open all the time on surface and during dives. I had isolator I had trouble closing on land, there was no way someone could do it underwater. So at least make you are shutting or checking your isolator. I personal shut mine after I fill my tanks incase of a leak or for traveling incase the valve gets bumped open, i dont loose all my gas. Its saved a dive or to for me and def found a leak or two.

[LCF]

One of the things that perturbed me about my Cavern/Intro class sequence was that the ONLY valve problem I had to handle was when my instructor swam up to me with a note on his slate, "Bubbles from behind you -- close isolator!" Yes, I was able to reach back and close the isolator. But I showed no poise, no diagnostic ability, and no team skills.

In my subsequent, repeat class, I handled many valve failures (indicated by air-gun). But I didn't have to handle a roll off, because the instructor was forbidden to close our valves. It was actually in a recreational helium class, when an instructor first faced me with a roll-off situation -- I handled it fine.

My cave instructors told me that their goal is that, when you encounter a problem underwater in a cave, you will shrug and say, "Oh, not THAT again . . ." I have to say that, at least to date, they succeeded with me.