Can you reach your tank knob to turn it on?

[espenskogen]

This is definitely for a single cylinder still....and note that even a dual outlet valve is only 'recommended' - not required. There is no requirement for another redundant cylinder such as a pony or whatever.
I don't know about other agencies at this entry level stage.

Possibly - I don't teach IANTD - However for the cavern and overhead environment course from Padi, it has to be taught within the daylight zone, and with no more than 40 meters distance horizontally and vertically from the surface.

So even so, you can still do a cesa if you have to. But the better option would be to get your buddy's AAS, as he's likely to be far closer than 40 meters anyway.

For any more challenging overhead environment courses, it would be absolutely NUTS to do it without redundant air - Regardless what the standard says. If IANTD runs the cavern course as a tech course, then allowing the course without redundant gas does nothing to validate diving with only one gas supply - It only highlights the insufficiencies of the standards. Surely the whole point of a cavern or cave course is to allow for exploration safely. In my opinion, doing so without redundant gas, is as dangerous as it can get.

 

[jonnythan]

I don't know if anyone mentioned this, but a valve that is barely on can breathe fine at the surface, but suddenly not give you enough air at 75 feet.

Reaching behind your head to turn your valve fully on is a quick easy fix.. compared to trying to get your buddy's attention while you ascend and hoping he understands what you're triyng to tell him.. and hoping he doesn't turn the valve the wrong way.

 

[Kim]

Possibly - I don't teach IANTD - However for the cavern and overhead environment course from Padi, it has to be taught within the daylight zone, and with no more than 40 meters distance horizontally and vertically from the surface.

So even so, you can still do a cesa if you have to. But the better option would be to get your buddy's AAS, as he's likely to be far closer than 40 meters anyway.

For any more challenging overhead environment courses, it would be absolutely NUTS to do it without redundant air - Regardless what the standard says. If IANTD runs the cavern course as a tech course, then allowing the course without redundant gas does nothing to validate diving with only one gas supply - It only highlights the insufficiencies of the standards. Surely the whole point of a cavern or cave course is to allow for exploration safely. In my opinion, doing so without redundant gas, is as dangerous as it can get.

I would agree with you. The IANTD course is also taught within the daylight zone although they don't have the distance limits as far as I know. Still.....even with PADI, if you're 20 meters down and 20 meters in personally I'm not convinced that everyone will make it out and up with one lungful of air! By the way...the IANTD course is listed under their Sport diver section so it's still actually on the Rec side....not technical. Anything more serious changes the requirements considerably.

 

[espenskogen]

I would say though that the main reason an ordinary diver might want to be able to reach his valve is for when he jumps in with it turned of. It can really ruin your day if you can't reach it.
I never understand the problem some seem to have with this very simple skill. You just make sure that your tank is set up so you can reach it and then IF you ever need to, you can. Where's the problem with that?

Like you said......'It's not exactly rocket science you know!'

I agree - this is the main reason you'd want to reach your valve, and I'm not in disagreement that this is useful and nice. But it's not critical IF you stick to proper predive safety checks.

To jump in without the air turned on is an entirely avoidable problem which is in its entirety down to complacency during your checks.It simply is NO excuse for jumping in with your air turned off.

So basically, I agree that it's a good thing to be able to do. But if you didn't totally mess up before you even entered the water, you will never need it in a real world scenario.

 

[espenskogen]

I don't know if anyone mentioned this, but a valve that is barely on can breathe fine at the surface, but suddenly not give you enough air at 75 feet.

Reaching behind your head to turn your valve fully on is a quick easy fix.. compared to trying to get your buddy's attention while you ascend and hoping he understands what you're triyng to tell him.. and hoping he doesn't turn the valve the wrong way.

This is true - But when you do your checks, you will see that your pressure gauge is dropping and rising with every breath. So as I've said above, there simply is no excuse for jumping in with your air turned off, or almost off. If you do (as in screw up on the boat before you even hit the water) then sure it's helpful to reach your own valve. My point though, is that you should NEVER EVER need to.

 

[Kim]

But if you didn't totally mess up before you even entered the water, you will never need it in a real world scenario.

Again I agree. Me.....I like to cover my bases to include that one lapse of concentration or 'Murphy's Law' moment. In all honesty I've never needed it in reality....and I hope I never will. I agree with something I saw JeffG write recently:

Hope for the best, but plan for the worst..

(if I've remembered his quote accurately!)

 

[espenskogen]

Again I agree. Me.....I like to cover my bases to include that one lapse of concentration or 'Murphy's Law' moment. In all honesty I've never needed it in reality....and I hope I never will. I agree with something I saw JeffG write recently:

(if I've remembered his quote accurately!)

We're on the same page. Personally, I can reach my valve on both my single and twin setup. The point I was making was that the skill is nowhere near as valuable as being able to do a reg recovery. In fact, it's probably so far down the list that a snorkel/regulator exchange is a more valuable skill.

E

 

[dherbman]

It's not exactly rocket science you know..

Right, it's simple math. How much time do you have when your tank is in a full out freeflow, starting with 1000PSI? How long to do a safe ascent from 90'?

BTW, the last time I saw this scenario play out was in February.

 

[KMD]

So basically, I agree that it's a good thing to be able to do. But if you didn't totally mess up before you even entered the water, you will never need it in a real world scenario.

What happens if the upline or anchor line gets caught beween the valve and tank during descent or rubs against it during ascent and you have a partial for complete rolloff?

 

[Kim]

What happens if the upline or anchor line gets caught beween the valve and tank during descent or rubs against it during ascent and you have a partial for complete rolloff?

Depends if you can reach your valve or not!

Me....I'd just turn it back on! eyebrow