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The DSMB means PUT THE KETTLE ON !!
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Discussion Starter · #1 ·
Hi All,

Can i get views on something please... Im new as you all know and going to be using twin 7s as opposed to a 15 shortly.. Now i understand the setup for twins but the question i have is ... As i am not going to be using them independently for the forseeable future, Is there a reason why i cant u use my R395 Octo as the alternate second stage on the second first stage (if you follow that lol)

I basically see the way i want to use them as a big 14 cylinder that can be isolated if required, almost no different to the way im using my 15 at the mo. If i had a failure then id be getting out just as i would with a single, but i see the only difference is i might be able to salvage some air to get out with

Any thoughts or comments would be apprecieted.

Cheers, AndyG.
 

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Is there a reason why i cant u use my R395 Octo as the alternate second stage on the second first stage (if you follow that lol)

I basically see the way i want to use them as a big 14 cylinder that can be isolated if required, almost no different to the way im using my 15 at the mo. I
As you say, they will act as a 14l single. A couple of things to be wary of......
  • Make sure the isolator is open, otherwise you are on a single 7
  • Be aware that, in theory, it might be possible for the other valve to open, leading to gas loss. It can happen going down a shot line, contact with wrackage etc. Not often, but it's why twinset divers do flow checks and valve drills:)
  • Hose routing might suffer, depending on what post you put the reg on, as drysuit hosand bcd hoses might seem a couple of inches shorter.
Having said that, any particular reason why you can't just get another first stage?
 

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The DSMB means PUT THE KETTLE ON !!
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201 Posts
Discussion Starter · #3 ·
Hey Londonsean69

Thanks for the reply... i DO intend on having two first stages on the set, Its more questioning the reason on why i would need to buy another second stage (S600) when i would not intend to use it that much and i have a brand new R395 on my current setup. I would also have an SPG on each first stage too just to make sure i knew if gas wasnt on, or not emptying in sync.

Does that make more sense ??

:)
 

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Your use of the word independantly has thrown me a little. What do you mean by using them independantly, as they are already manifolded.

Personally, I would dive them as normal twins, and only bother with one SPG. An R395 is a fine reg to use as your backup reg.

It would have been a lot easier to ask "Is an R395 OK to use as the backup reg on a twinset";)
 

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That's Members Representative to you!
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Sorry for the confusion, i meant independently as some divers put different mixes in each side and regularly swap regs about.
Different mixes in twin 7's? Rather them than me....

Have a look at the DIR setup for twinsets - to be fair you can't really go wrong with their setup and thinking for diving twins...
 

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The worlds slowest sailor.
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2,970 Posts
Hi All,

Can i get views on something please... Im new as you all know and going to be using twin 7s as opposed to a 15 shortly.. Now i understand the setup for twins but the question i have is ... As i am not going to be using them independently for the forseeable future, Is there a reason why i cant u use my R395 Octo as the alternate second stage on the second first stage (if you follow that lol)

I basically see the way i want to use them as a big 14 cylinder that can be isolated if required, almost no different to the way im using my 15 at the mo. If i had a failure then id be getting out just as i would with a single, but i see the only difference is i might be able to salvage some air to get out with

Any thoughts or comments would be apprecieted.

Cheers, AndyG.
seems a complicated way of having 200 lts less gas.

why not get a small stage cylinder?

2p
 

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Platinum Member - I wish...
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im using my 15 at the mo.
If your using a 15L at the moment, an on dives you are using bulk of the gas then if you get twin 7's you and want to do a two dive day you are going to need two sets which could get rather expensive.

You could always use your 15L to decant out of I suppose.

Or if you gas usage is inbetween, you could always get a 8.5lt twinset and hopefully get two dives from that. (Though atm think it's just Halcyon importing them so new, it's not the cheapest option.)

If you know/have worked out your SAC, always a good idea to run some profiles through Suunto dive manager and see what is realistically possible with the size of cylinders.

Matty
 
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