Twin tanks: manifold or redundant

[TSandM]

I don't think that back-mounted, manifolded doubles are the best recipe for easy access to valves, but I think it should be possible for virtually anyone to learn to reach and manipulate their valves in an expeditious fashion. It took me a long time, and in the end, I had to change exposure protection to optimize it, but in every drysuit I have owned, I have been able to reach and close my valves. It does take work.

If you are unable to close your valves, you should either dive a system where you can reach them (eg. sidemount) or keep your dives where you don't need the redundancy (in which case, why dive doubles?)

 

[ianr33]

I've used independent doubles, manifolded doubles and sidemount.

For diving with a buddy in open water ,or good sized caves, makes no big difference to me which I use.Ideally I would go with manifolded doubles.

Open water solo dives I prefer NOT to use manifolded doubles. Not so much because the gear might fail but because I might. In the worst case scenario of a roaring mass of bubbles behind your head you need to react quickly (Within a minute or so) and react correctly. Get it wrong and you die. While I'm 99% sure I would fix the problem and abort the dive I prefer the peace of mind I get from independent tanks.

In tight caves ,or ones with extremely high flow sidemount is the way to go IMHO.
Sharing air from way back in a silty cave with a bunch of restrictions along the way is not something I ever want to roll the dice with.
I know someone who switched regs on sidemount only to find the tank was empty. How did that happen? The flow was so strong it had freeflowed the reg. Freeflow was not noticed as the bubbles were going horizontally and not heard due to the roar from the flow. Had he been in backmount then he would have been OOA

 

[TSandM]

Had he been in backmount then he would have been OOA

Although, in backmount, he would have had one reg in his mouth and the other directly below his chin. It is difficult not to notice a freeflow from a necklaced regulator (although not impossible).

 

[DaleC]

If you are unable to close your valves, you should either dive a system where you can reach them (eg. sidemount) or keep your dives where you don't need the redundancy (in which case, why dive doubles?)

I don't agree with this theoretically but I do in reality (if that makes sense). If you are diving a manifold it is true but the value of independants is that redundancy does not depend on closing the valve. That's the theory but I in reality I do like to be able to work my valves. I have left/ right valves so my twins looks and acts the same as a manifold setup just sans the isolator. It is also about 2" narrower as I don't use metal bands.

 

[elan]

My Cave 2 instructor does his valve drills by shutting down the right post and isolator at the same time -- I haven't tried it yet, but I watched him, and it's clearly possible.

In doing scenario-based training in warm water, with no hood, I've found it pretty easy to identify the side where the bubbles are. In cold water, I'm not as good at that, and I also don't have anywhere near the ability to FEEL the bubbles behind me. Of course, in cold water, I doubt I'd be able to reach a post and the isolator at the same time, either (although I have not tried this).

Try most likely your doubts will go away.

Just out of curiosity I tried to do it today. We were diving 36F water and I was wearing my cold water set - 200 gram undies + under armor set with extra 200 gram vest. I could do it fairly easy without even taking the light off the left hand. It was no more difficult than reaching the valves during regular drill.

 

[Sas]

Try most likely your doubts will go away.

Just out of curiosity I tried to do it today. We were diving 36F water and I was wearing my cold water set - 200 gram undies + under armor set with extra 200 gram vest. I could do it fairly easy without even taking the light off the left hand. It was no more difficult than reaching the valves during regular drill.

Hahaha, yea I tried it on the weekend too after reading that post. No worries here either.

 

[Kern]

Try most likely your doubts will go away.

Just out of curiosity I tried to do it today. We were diving 36F water and I was wearing my cold water set - 200 gram undies + under armor set with extra 200 gram vest. I could do it fairly easy without even taking the light off the left hand. It was no more difficult than reaching the valves during regular drill.

Hahaha, yea I tried it on the weekend too after reading that post. No worries here either.

WHAT!!!!

You can't learn to dive on the intrawebs. You chaps will surely die! :mooner:

 

[Sas]

WHAT!!!!

You can't learn to dive on the intrawebs. You chaps will surely die! :mooner:

Chap??

Ok I'll forget I ever read this thread

 

[Kern]

Chap??

Ok I'll forget I ever read this thread

Well, in todays PC world, where we have a girl actor & steward rather than actress & stewardess I'm sure we can have girly chaps.