double tank equipment

[agilis]

Both tank valves need to be open when you fill manifolded doubles?

There is plenty of comedy in this thread, that is for sure.

If you want to fill both tanks simultaneously, yes, I'd assume so. Or you can do them one at a time, if you wish, but that's manifestly obvious.

 

[Adobo]

If you want to fill both tanks simultaneously, yes, I'd assume so. Or you can do them one at a time, if you wish, but that's manifestly obvious.

Oh, this is just precious.

Just to be clear, in this scenario, talking about doubles with an isolation manifold, in your mind, I am the unskilled/incompetent and you are the highly skilled. Is that right?

 

[agilis]

Let's keep this simple. I asked you to provide a *single* notation in the literature to support your conclusions regarding Dunning-Kruger.

Not 4 paragraphs of nonsense, just a single citation.

Still waiting.

Tobin

A single citation of what? I applied the logic of D-K, an observed phenomenon, to a specific set of circumstances. The tendency of the less skilled to overestimate themselves while underestimating others, and the tendency of the more skilled to underestimate themselves while overestimating others, is the heart of Dunning- Kruger.

The situational applications of this phenomenon are essentially limitless. I expected you to easily follow the logic that, within the D-K construct, the less skilled, underestimating the ability of others, are more likely to assume that other people require some sort of training intervention.

 

[cool_hardware52]

A single citation of what? I applied the logic of D-K, an observed phenomenon, to a specific set of circumstances. The tendency of the less skilled to overestimate themselves while underestimating others, and the tendency of the more skilled to underestimate themselves while overestimating others, is the heart of Dunning- Kruger.

The situational applications of this phenomenon are essentially limitless. I expected you to easily follow the logic that, within the D-K construct, the less skilled, underestimating the ability of others, are more likely to assume that other people require some sort of training intervention.

Eventually even cats get tire of their mouse, but one more time, a specific citation that supports your "conclusion" that the unskilled would "obviously prescribe" the skilled seek more training. I find this no more obvious than your hilarious claim that the proper operation of a manifold is obvious.

As seen here in your post #68

The unskilled group will obviously prescribe unnecessary formal training for some of the simplest functions, while the highly skilled might assume anyone certified to do something can figure things out on their own.

I've seen nothing in the literature to support this conclusion. I'd suggest the reverse is true.

Tobin

 

[agilis]

Oh, this is just precious.

Just to be clear, in this scenario, talking about doubles with an isolation manifold, in your mind, I am the unskilled/incompetent and you are the highly skilled. Is that right?

Not at all. I have never used one. The diagrammatic descriptions are all I have to rely on, along with watching them being filled. The diagrams seem to suggest a manifold shared by two first stages and two gas bottles, each with its own valve, and a communicating valve that permits the isolation of one tank or the other.

My logic is that if a bottle's dedicated individual valve is closed it cannot be either filled or emptied. That is the only assertion I made. Beyond that, my only experience with doubles is with those that have a common valve that cannot isolate one tank from the other, and which consequently function as a single tank.

I have no interest in the double regulator isolation manifolds, but they seem reasonably straightforward. No rocket science involved just some valve arrangements. Plumbing, in effect.

---------- Post added June 18th, 2015 at 06:20 PM ----------

Eventually even cats get tire of their mouse, but one more time, a specific citation that supports your "conclusion" that the unskilled would "obviously prescribe" the skilled seek more training. I find this no more obvious than your hilarious claim that the proper operation of a manifold is obvious.

As seen here in your post #68



I've seen nothing in the literature to support this conclusion. I'd suggest the reverse is true.

Tobin

As simply put as I can manage, those who underestimate the skills of others are more likely to assume that other people need training than those who overestimate the skills of others.

Forget these fustian references to 'the literature', usually inappropriate when examining individual applications of a general principal. You sound like a graduate student.

 

[cool_hardware52]

Not at all. I have never used one. The diagrammatic descriptions are all I have to rely on, along with watching them being filled. The diagrams seem to suggest a manifold shared by two first stages and two gas bottles, each with its own valve, and a communicating valve that permits the isolation of one tank or the other.

My logic is that if a bottle's dedicated individual valve is closed it cannot be either filled or emptied. That is the only assertion I made. Beyond that, my only experience with doubles is with those that have a common valve that cannot isolate one tank from the other, and which consequently function as a single tank.

I have no interest in the double regulator isolation manifolds, but they seem reasonably straightforward. No rocket science involved just some valve arrangements. Plumbing, in effect.

Dead wrong.

Let's take a look at your powers of logic.

1) If one reg / oring / hose fails and that "post" is turned off how does the diver access the gas in *both* tanks if what you say is true?

2) If either "post" functions as your logic and years of experience lead you to believe what is the purpose of an Isolation valve?


Here is the reality: Each "Post" only controls the orifice in that post. The manifold communicates with both tanks all the time. This is true with or without an Isolation valve. The Iso valve will Isolate one tank, and it's associated "post" from the other.

Normal good practice at the fill station is to connect a whip to *ONE POST* Open that one valve, *and* the Iso valve (which should be open pretty much all the time anyway) and fill both tanks. The gas flows in through the post in to the first tanks *and* through the manifold into the second tank. Ya, I know this runs counter to your logic and counter to what you claim to be obvious, but that's how it works in the real world.

Filling with the Iso closed has lead directly to fatalities, apparently logic and er, uh, well obviousness wasn't quite enough.

Didn't they cover all this in your BOW class like Stoker claims? Color me shocked.

Tobin

 

[Adobo]

Not at all. I have never used one. The diagrammatic descriptions are all I have to rely on, along with watching them being filled. The diagrams seem to suggest a manifold shared by two first stages and two gas bottles, each with its own valve, and a communicating valve that permits the isolation of one tank or the other.

My logic is that if a bottle's dedicated individual valve is closed it cannot be either filled or emptied. That is the only assertion I made. Beyond that, my only experience with doubles is with those that have a common valve that cannot isolate one tank from the other, and which consequently function as a single tank.

I have no interest in the double regulator isolation manifolds, but they seem reasonably straightforward. No rocket science involved just some valve arrangements. Plumbing, in effect.

I'll concede that you clearly have diving experience. I don't have the wherewithal to assess how much experience you have based on our brief interactions on this thread. But clearly, you know a lot about diving.

Which only reinforces the argument that anyone who is embarking on diving doubles for the first time would benefit from instruction from a competent resource. Because even someone who has as much knowledge as you do, wasn't able to figure out the proper operation of the valves and manifold based on looking at diagrams and schematics.

Finally, I'd like to say that it really wasn't very nice of you to say things such as:

I don't mean to sound antagonistic, but I feel like I'm having a conversation with an adolescent suffering from assburgers.

Your remarks about my age are a sad commentary on your moral construct. Do you really think any of that indoor Plunbing/Couteau stuff was clever?

I agree that there is a lot of misinformation and lack of accuracy surfacing in various posts. One need look no further than your amateurish stuff.

Actually, you do sound like a kid.

I think the reality is that you are out of facts, very short on practical information with only moderate experience and bereft of any logical consistency. A formalistic zombie with the zeal of a convert.

Writing that everything is incorrect without any specificity suggests a limited knowledge base and a tiny mind.

I mean, my knowledge on this topic, limited as it is, is from personal research, formal training and personal experience diving using this configuration in a range of environments. Not to mention that I belong to a dive club with a majority of divers using doubles almost exclusively.

Whereas your knowledge on this topic comes from, well... never mind.

I am sorry that I was not better able to adequately express the more important points of using doubles. If I had, perhaps this conversation would have gone a lot better.

And I think I'll just leave it at that.

 

[agilis]

I'll concede that you clearly have diving experience. I don't have the wherewithal to assess how much experience you have based on our brief interactions on this thread. But clearly, you know a lot about diving.

Which only reinforces the argument that anyone who is embarking on diving doubles for the first time would benefit from instruction from a competent resource. Because even someone who has as much knowledge as you do, wasn't able to figure out the proper operation of the valves and manifold based on looking at diagrams and schematics.

Finally, I'd like to say that it really wasn't very nice of you to say things such as:







I mean, my knowledge on this topic, limited as it is, is from personal research, formal training and personal experience diving in a range of environments.

I am sorry that I was not better able to adequately express the more important points of using doubles. If I had, perhaps this conversation would have gone a lot better.

And I think I'll just leave it at that.

You are correct in that I misinterpreted the operational details of an isolation valve, based not so much on schematics, which I've barely glanced at, but more from somewhat disinterestedly (not uninterestedly) watching them being filled at my local dive shop. Thanks for the brief lesson. I doubt I'd need much more were I to decide to use this kind of arrangement. Certainly no course of formal instruction. I'm a fairly good amateur plumber and the principles involved are not especially different.

I got involved in this string because I was interested in finding an updated version of the simple single regulator doubles setup with twin 40s I used a long time ago, not for longer diving duration but for better weight distribution, something that has become increasingly important as I approach my mid-70s. I was successful in this quest, and it seemed to me that the purpose, the reason for wanting to use doubles, and the way in which they would be used were important factors in determining the need for any significant preparation.

I got involved in this more heated discussion because it seemed obvious to me that a properly trained diver should know that they must familiarize themselves intimately with new equipment, and because doing so is not all that difficult. Just basic plumbing, in this instance, with the added elements common to all diving involving breathing gas under pressure, something I've been doing for well over 50 years.

I mention this experience not to assert any special ability or skill; I no longer do any deep or cold water diving, and dive between October and July only in the tropics. Just like a typical vacation diver, which is what I've become. It was not always so, but why go back to a period before indoor plumbing when Moses walked the Earth. Much of my experience is irrelevant.

I have seen a lot though, and managed to do my first few years of diving with no formal instruction, to make the switch from double to single hose regs, to learn to use SPGs instead of J valves, to learn to use BCDs (even now I do very shallow dives without one), to use a computer, rebuild my own regulators and valves, and a number of other developments over the years, all without any formal instruction and managing a couple of thousand dives without any untoward incidents.

I apologize for anything I wrote that was offensive, but it seemed to me that I was as much sinned against as sinning. I have a tendency to bite back.

 

[DaleC]

Sigh... this is why I prefer to argue ideas rather than personalities.

One thing I have learned over the years is that the internet does not do well in terms of transmitting the subtle parts of conversation, so that people (myself included) can often get hung up on arguing what they perceive the other is saying. The same with responding to the OP. When I took my fundies course, something I was a little worried about because of some heated debates I have had on the board, I worried it would be antagonistic. The reality was that IRL we were as careful about how we said things as we were about what we said. Something that gets a little lost here.

When I think of instruction I see three pathways: Formal, Informal (mentoring), and Self taught. I really don't see any one being exclusive as I have benefited from all three. It is often mentioned that informal education can be unreliable because the mentor may not know everything, which is true. But I think we could also look at the quality of formal education in that regard. high standards in regard to formal instruction in the dive industry leaves a lot to be desired.

Formal instruction also carries the subtle potential for passive learning, wherein the student switches off critical thinking and relies on another to present relative information. It also puts the onus of improving on the instructor. If there is a deficiency people will commonly say "they were not taught well" whether that is true or not.

Self educated people tend to more actively engaged (again I am speaking in generalities and I am sure everyone can find an exception). The onus is on the individual and if there is an issue it would be commonly said "they did not learn well" which would be true. It is very hard to blame anyone else for your deficiency when you are self taught. And most self taught people know that.

As to knowing/not knowing what you don't know. The internet today contains a plethora of information and is an excellent vehicle for the spread of information to people in a wide geographic region. That fact is not lost on most, if not all of the agencies who offer portions of their courses online. The internet also allows a back and forth discussion that one does not get in books. All one really needs is the basic ability to verify what one is learning with several sources to see if it is valid or junk.

To me, formal education has a definite role in my learning. I see it as valuable when what I need to know involves a large paradigm shift and I do not have enough prerequisite understanding to be able to discern what is valid and what is junk, or to grasp concepts. I am terrible at math, and never took physics, so EAN, at the time, was a good example of such a shift. For others, EAN is very ground level academic stuff and they can learn it all from less formal sources.

Diving doubles for me was like that. I already had a good grasp of the basics of diving, managing more than one air source, weighting issues etc... so I did not feel I needed a "formal course" to start using them. I just applied the same style of incremental exposure that I used for many other ideas and verified my experiences as I went along.

Answering a question such as the OP with good information can't hurt IMO. If they have common sense they will follow up with more questions and then assess whether they can grasp the concepts informally or if the subject is more than they imagined and realize they need a formal course. I engage people as if they had common sense until they prove otherwise and don't just assume, because of the nature of the first query, that they must be as confused as their question might be... especially if there is a language issue.

Saying "take a course" may be part of the discussion, but to offer it as the end of discussion (not saying that happened here) just sends people away with no more understanding than when they started. I feel the value of a discussion board such as SB is that it allows us to share ideas. And that brings us back to ideas, points of view and perspective. Invariably, when we argue we do so from our own experience. Those from the formal camp have theirs, those from the informal theirs and those from the self taught theirs. Which one is right(er) depends on how well the ideas are transmitted, and the particular orientation of the receiver. People tend to learn best, and gravitate towards, their particular style of learning.

From the limited exchange of the OP I can't determine what that is for them yet so I just present the best case information from my POV and trust that they will take what they need and leave the rest.

 

[DaleC]

I can understand your perspective partly because I know you spend a great deal of time talking to people in a business sense about things they do not know. You see this day in and day out.

But if scuba is full of people that need help replacing an LP hose perhaps the formal model of education, which has been in effect for nearly 50 years, isn't working so well. Most of the informal/self learners I know take far more responsibility for knowing their equipment than that. We share field repair tips with each other at dive sites and garages all the time. A good example of this is the education night we host at our club annually. There we learn how to do the basics like open the second stage, tighten schrader valves, correct OPV issues, replace spindles in SPG's etc...

On the other end of the spectrum some people are so invested in the "dive professional" model that they become lazy, are afraid they will screw something up, or have been told it is all life support equipment and can't be tampered with by non professionals long enough not to even try to learn.

I'm not anti professional either, but I am somewhat jaded as to what passes as such in diving. I have had "professionals" tell me my steel tanks are no good because they are more than 20years old and prone to cracking. When I try to explain the difference between 6351 Al and Steel I can tell they have no idea what I'm talking about. They have adopted the power of veto without understanding the rationale because they are now unquestioned as professionals. I think the professional class in diving could use a good shaking up that way to separate the wheat from the chaff and I will admit arguing sometimes to try to achieve that effect.

Another example is when I say I dive sometimes without SPG or BCD. I am told either it can't be done, or is patently unsafe. I don't always blame them really because they don't know what they don't know (to coin that phrase). They were educated and certified to teach diving without being exposed to those basic diving techniques. Of little consequence when just one more opinion but a little sad when it carries the weight of professionalism with it.