Using back mount doubles as single tanks

[BlueTrin]

I'm only assuming based on the thread that I linked that those found dead with a gas left panicked. Maybe some were medical incidents, who knows. Maybe narked? I don't know.

I agree that you "should" be able to form a skill set that prevents or greatly minimizes the chance for there to be an issue.

I've never ran out of gas, I've never had an isolator issue, I "think" I've trained these issues out of my human brain, but never is a strong word. Humans inevitably make mistakes. That's a guarantee. We've all shown up to a dive either without fins, or forgot the hood.. maybe no lights. Why is the manifold any different? I would like to think that it can't happen to me, I've trained it out, but people with worlds more experience then me have died with air left. Enough people to pause and think based on that other thread (that no one seems to have actually read).


I don't know why it would happen, I just have it in the back of my mind that it can happen.

Where's Gareth Lock when you need him!?! Lol. I think he does worlds better at explaining the human factor, which will make mistakes one day. We all do. I don't have answers for any of it, I still dive with an isolated manifold just like you all do.

So I am not saying that manifolded is 100% safe. I am saying that before to switch to independent, you need to see what you lose vs what you gain.

Trying to fixate on the problems of manifolded to say that I should go indies without checking in a pro vs cons manner is a bias.

It is unclear to me that I would be safer by switching to manifolded, but happy to discuss. Also I reckon that I am slightly paranoid when I dive and I perform a lot of checks so it may not work for someone else equally.

 

[rob.mwpropane]

I just wanted to point out that there are ways of mitigating the risk of human mistakes with isolator valves, other than eliminating it. Training, procedures and practice all contribute to dealing with the human factors. If you think the risk of a closed isolator is too high, why not change the procedures to mitigate it? You could use checklists, always analyze both posts, use buddy/team confirmation and pre and post splash protocols. Pretty sure Garett Lock dives with an isolator when he's on OC...

I dive with an isolation valve, so I'm not disagreeing with anything anyone said, I just think it's good to know there are pros and cons to both ways. I think it's fascinating that there are different views in the subject and even more fascinating that people with 1000's of dives actually lean the other way.

At 1st glance one would think a manifold set of doubles is the safest thing there is. No matter what you have at least 50% of gas remaining, but apparently there is more to it.

So I am not saying that manifolded is 100% safe. I am saying that before to switch to independent, you need to see what you lose vs what you gain.

Trying to fixate on the problems of manifolded to say that I should go indies without checking in a pro vs cons manner is a bias.

It is unclear to me that I would be safer by switching to manifolded, but happy to discuss. Also I reckon that I am slightly paranoid when I dive and I perform a lot of checks so it may not work for someone else equally.

? I never said go ID. I have zero experience with that setup, I've just seen a few guys use it. I think before you switch to any system it's important to understand the risks of that system... kind of where this conversation is I think. Anyone saying "my way is the best, the only way" is sort of defeating the purpose of having an open discussion.

I LOVE my manifolded with isolation valve back mount doubles.. so much so that I have 7 sets! I just "try" to keep an open mind and not get sucked into some dogma that keeps me from learning something new.

 

[steinbil]

I dive with an isolation valve, so I'm not disagreeing with anything anyone said, I just think it's good to know there are pros and cons to both ways. I think it's fascinating that there are different views in the subject and even more fascinating that people with 1000's of dives actually lean the other way.

At 1st glance one would think a manifold set of doubles is the safest thing there is. No matter what you have at least 50% of gas remaining, but apparently there is more to it.


? I never said go ID. I have zero experience with that setup, I've just seen a few guys use it. I think before you switch to any system it's important to understand the risks of that system... kind of where this conversation is I think. Anyone saying "my way is the best, the only way" is sort of defeating the purpose of having an open discussion.

I LOVE my manifolded with isolation valve back mount doubles.. so much so that I have 7 sets! I just "try" to keep an open mind and not get sucked into some dogma that keeps me from learning something new.

I appreciate the argument, as it has helped me solidify my own understanding and confidence in my choices, and I think it is valuable to keep an open mind and question the dogmatic "truths". I have, however, come to see that the experienced DIR crowd usually have very good reasons for their choices and most are willing and able to articulate convincing reasons for why the standards are what they are.

 

[BlueTrin]

I dive with an isolation valve, so I'm not disagreeing with anything anyone said, I just think it's good to know there are pros and cons to both ways. I think it's fascinating that there are different views in the subject and even more fascinating that people with 1000's of dives actually lean the other way.

At 1st glance one would think a manifold set of doubles is the safest thing there is. No matter what you have at least 50% of gas remaining, but apparently there is more to it.


? I never said go ID. I have zero experience with that setup, I've just seen a few guys use it. I think before you switch to any system it's important to understand the risks of that system... kind of where this conversation is I think. Anyone saying "my way is the best, the only way" is sort of defeating the purpose of having an open discussion.

I LOVE my manifolded with isolation valve back mount doubles.. so much so that I have 7 sets! I just "try" to keep an open mind and not get sucked into some dogma that keeps me from learning something new.

Agree I think that’s very sane to question everything so you are confident with your choices.

Maybe I used the wrong words, but it was not aimed at you, only doing the same than you: trying to not fall in a dogma and not looking in “isolation” () to one side by proposing some counter arguments. Apologies, it was not intended to be a dig.

I guess on the ‘con’ side: it is probably easier to forget to check your secondary since you won’t switch regularly during the dive. So if you were rushed and somehow skipped some checks and have a failure maybe you switch to a reg that won’t deliver?

 

[PfcAJ]

Do you know if either of the burst disks had been recently serviced... or not ever?

Of the isolator or L / R valves?

Did you know that the founder of the WKPP and namesake of the Hogarthian system, who is still an active cave explorer, doesn't use an isolator on his doubles... he uses straight bar (this is an excerpt from another member on this forum, but I'm not sure if he wants to be dragged into this discussion so I just copy pasted).

I'm not really arguing against isolators, I like mine, I use it. Just playing devils advocate. When anyone says "this is the only way" and then I hear of guys with many moons diving saying the contrary it's a good discussion to have.

Fun fact; just this afternoon I was working on my car changing fuel injectors. Had to spin a nut in a precarious situation upside down behind the engine and low and behold... I spun it backwards a few times before I realized what I was doing. No panic, no fear, just an honest mistake. I threaded pipe for a lot of years, so this is really really uncalled for, but I'll admit I did it. I can 100% see how in a panicked diver turning the valve the wrong way can happen.

To my knowledge they were serviced and the leak was caused by ceiling impact.

Crossbar leaks. The barrel o rings that interface with the valves.

I am aware of the config Bill Main uses. I don’t really care what Bill Main uses. Good guy, done a lot, doesn’t dive with the WKPP anymore.

There are plenty of ways to do things. Some better than others.