One SPG only..?

[Albion]

Where's your buddy?

I dont know it was YOUR dive that i was turning into a CF (not your fault, i just started off with where you were at and added a failure)

I got slammed with the dark narc. I thumbed it and my buddies waved 'goodbye'

Ok i guess you were pre DIR then, but what if...............

I'm curious, why would you shut off the manifold? If the post is freeflowing, just shut the knob and you still have access to that gas, right?

Did i say 'only' the valve was free flowing??? i said Massive freeflow, i guess you are now advocating manifolds with out a valve on them, one less failur epoint huh? Have you ever dived doubles?

Anyway, you should have gas planned for just such an occurence and you stick to your plan exactly, immediately after you turn the dive. That's what proper gas planning is all about.

Proper gas planning doesnt account for a massive freeflow, that is what i am hypothesizing (spell check it for me). Spectre said he was down to 1200psi and heading back to the line (he should have turned the dive earleir, but what if he had been entangled for instance hence late turning the dive).

Just for a moment back away from the DIR classroom answers, and think, if this happened what would i do?

I repeat i dont have a second gauge or plan to get one, but if the above happened and it isnt unreasonable, a second gauge would give you data to help analyse your predicament. As it is i would head up so that i was in a position to use my deco gas when the primary shut down. If i had a proper DIR buddy with me this wouldn't be such a CF.

 

[jagfish]

I understand what Jonnythan is saying here,

"I'm curious, why would you shut off the manifold? If the post is freeflowing, just shut the knob and you still have access to that gas, right?"

But I totally miss how your response has anything to do with what he said...

Did i say 'only' the valve was free flowing??? i said Massive freeflow, i guess you are now advocating manifolds with out a valve on them, one less failur epoint huh? Have you ever dived doubles?

 

[jonnythan]

Did i say 'only' the valve was free flowing??? i said Massive freeflow, i guess you are now advocating manifolds with out a valve on them, one less failur epoint huh? Have you ever dived doubles?

I readily admit I have not dived doubles, but it is almost certain the actual valve is having a problem, not the seal at the tank neck.. so simply shutting off the post will presumably solve the problem, leaving the contents of both tanks accessible, right? What failure were you envisioning?

Proper gas planning doesnt account for a massive freeflow, that is what i am hypothesizing (spell check it for me). Spectre said he was down to 1200psi and heading back to the line (he should have turned the dive earleir, but what if he had been entangled for instance hence late turning the dive).

Well that's what your last third is for. Unplanned gas loss, or unplanned increase in time to exit point, etc. If you have multiple failures, that's what your buddy is for. If 1200 psi wasn't enough for what he was doing he should have turned earlier, but maybe that was all he needed.

 

[Albion]

I understand what Jonnythan is saying here,

"I'm curious, why would you shut off the manifold? If the post is freeflowing, just shut the knob and you still have access to that gas, right?"

But I totally miss how your response has anything to do with what he said...

ok free flowing is not the best word, let say failed, could be the tank o ring, could be the manifold to valve o rings. The manifold valve is there for a reason and we now need it!!!

You have just had a failure resulting in loss of gas (could be a lot, could be a little, you don't know anymore your valve is closed.
you may have had to also had to close the manifold (thats half as much gas that you dont know you have).
Even if you planned you gas responsibly, a combination of events could leave you with a dilema. how much gas do i have should i continue my deco plan or should i go up to where i could safely use my deco gas.

I am not trying to flame here, just asking the question. I dont think it is a consideration that would lead ME to take a second SPG. The orignal poster was asking a reasoned question, some of the answers have been simply 'you should know how much gas you have', 'proper gas planning would avoid this' they sound a bit smug to me and I dont think that is 100% going to be true. I am playing devils advocate and suggesting a failure combined with turning the dive being delayed could reasonably put you in a position where a second gauge could provide some meaningful data. Possibly using an AI computer in guage mode as your back up timer and right post SPG (THIS ISNT DIR DISCLAIMER).

 

[jonnythan]

ok free flowing is not the best word, let say failed, could be the tank o ring, could be the manifold to valve o rings. The manifold valve is there for a reason and we now need it!!!

Tank o-rings are slooooow leaks .. but point taken. So we need to shut down the manifold.

[blah blah blah, both of your tanks explode catastrophically]

So you use your buddy's gas. Even if you lose ALL of yours, he should still have enough to get your butt out of there, and that's the whole point. Anything you have in your tanks in the worst case scenario is just gravy. For practical purposes, your tanks will never totally blow up so you have enough gas to deal with the problem before you turn, even if you're pushing the ragged edge of your third.

 

[Uncle Pug]

Albion... the planned reserve takes into consideration the amount of gas needed to get both you and your buddy to your first gas switch. No need to change the plan... just implement it. An extra SPG serves no purpose. It is only another distraction and potential failure point.

 

[Albion]

Albion... the planned reserve takes into consideration the amount of gas needed to get both you and your buddy to your first gas switch. No need to change the plan... just implement it. An extra SPG serves no purpose. It is only another distraction and potential failure point.

Agreed the buddy is the saviour if one or all of these scenarios happened and it is a good example of why you should have one even with redundancy of equipment. But i did say we lost our buddy, like in Spectre's orignal story, he waved goodbye, but maybe separted due to someother scenario. (i am trying to make it tough here and see if enough failures would warrant an extra SPG :11: )
We lost our buddy, we have had an equipment failure and are down to one tank, with less than 1200psi, (thats what we had when the CF started) and we dont know how much leaked out before valves were shut and we are at 120 feet. (was going to add and we are being circled by white sharks but that would be silly, wouldnt it)
Dependant on the deco required, and based on my curent level it wouldn't be much obligation anyway, but my call would be to blow off the deep deco head to 30 feet. That would not require the use of another SPG, was wondering what others would consider.

This is DIR forum and only one SPG required, however it is an interesting topic and i just wanted to throw in this 'what if'

 

[VeniVidi]

[...] some of the answers have been simply 'you should know how much gas you have', 'proper gas planning would avoid this' they sound a bit smug to me and I dont think that is 100% going to be true. I am playing devils advocate and suggesting a failure combined with turning the dive being delayed could reasonably put you in a position where a second gauge could provide some meaningful data. Possibly using an AI computer in guage mode as your back up timer and right post SPG (THIS ISNT DIR DISCLAIMER).

Hello Albion

What you brought up is exactly the point of view I had 24 hours ago. However, this whole discussion left me with a lot of good input to think over. Now we must differntiate here very strictly.

This is the DIR forum. I have learned that planning and diving is executed ONLY and ALWAYS teamwise. That includes also gas management, which is conducted by the way very thoroughly. There is supposed to be NEVER a buddy loss whatsoever. Any incident that occurs will be solved by the involvement of the other team members. So DIR-like diving is, apart from the personal constitution, also a management type of task. Given these aspects, I can fully understand why no further instrument is required and will also consider that for application.

Now the sort of dives the both of us conduct, is not always like this. Be it because the people we dive with, are too heterogenous in their abilities and expectations. You might probably share my experience that sometimes buddies are of no great, no help at all - or worse - screw up the whole situation. This is also reflected in some of the fatality statistics.
Furthermore, the equipment of recreational divers vary much from each other. That is a fact that can be tolerated without problem in diving resorts where the equipment choice is not overly critical. Diving there, resembles more a catwalk rather than a sports center, anyway.

If you have to be solo competent because you are dealing with open water students, as a guide or for whatever reasons, the requirements on your configuration alter. I guess this sounds very heretic in the ears of a DIR-diver, yet this what I perceive from reality - and at this point I am most probably kindly requested to resume this discussion in another forum...

 

[Albion]

and at this point I am most probably kindly requested to resume this discussion in another forum...

ditto

 

[Spectre]

I dont know it was YOUR dive that i was turning into a CF (not your fault, i just started off with where you were at and added a failure)

You missed my point of my story. It was asked "to "who or what tells you that you stay cool if a calmity occurs?", and I was explaining that you can make an educated guess as to your ability to keep cool by looking at how you respond to problems:

"With experience comes confidence; as things happen you judge your reaction to them and make a call in post dive analysis if you were within your personal limits, close to them, or over them."

But to play along with your game, what would happen if I had a massive freeflow. Well, I'd probably have quit diving if I survived... I was in a single 80.

The question you asked was:

"Do you stick to your plan, or head up to 30feet so you can switch to your deco gas when back gas fails."

That was the question I was answering... "Where's your buddy".

You can throw enough failures to destroy any plan. What if your buddy then has their own freeflow and has to shut down a post? Right... your f-ed; you take your chances to get out the best you can. That's the point of the comment about not being able to anticipate for every failure.

That's why there are some dives you only do with some buddies, the buddies you trust unequivocally to cover your ***.

Adding an SPG doesn't give you any more gas. It's as simple as that. Your buddy has enough gas to get you out from the turning point; so your buddy has enough to get you out when your tanks end up empty. The second SPG doesn't keep you close to your buddy.