mahjong
Contributor
These are all interesting possibilities for diving indies doubles. However, the OP has a non isolation manifold. He would have to break that down by removing the crossbar to do independent doubles. FWIW, I would say it makes more sense to replace the plain crossbar with an isolation crossbar. Nothing lost from your indie doubles, and some options gained.
QUOTE=DevonDiver;6208298]Whilst not "wrong", the advice isn't optimal either.
Seek out a cheap 2st stage and an extra SPG... and you've got a fully functional set of indie-doubles. This'll bring lots of advantages; primarily that you'll have redundancy and surplus gas. I dive indie doubles all the time, including to teach many recreational dive courses. It's very convenient and provides a lot of options and safeguards.
Depending on your air consumption, you could still do two dives from the two tanks:
Dive 1. Breathe from the LHS tank, until you reach your reserve 50bar/500psi etc. RHS tank is for redundancy on that dive.
Dive 2. Breathe from the RHS tank, until you reach your reserve 50bar/500psi etc. LHS is for redundancy - you'll have the 'extra' reserve left from dive 1.
**That's kind what you were asking, but without the reg on the second tank, you'd lose the redundancy. This will also result in the tanks becoming 'imbalanced' as the drained tank gets more buoyant...and the untouched tank remains more negative. This can screw with your trim (and, hence, comfort) in the water.
Alternatively, you could 'balance' the tanks over 2 dives:
Dive 1. Alternate the tanks, breathing a set amount (i.e. 35bar/500psi) from each, before changing... and repeat.
Dive 2. Continue that process.
Lastly, you can utilise both tanks for single, longer/deeper dives:
Breath 1/3rd of the RHS tank. Switch to the LHS tank and breathe 1/3rd of that. Return to the RHS tank and breath that down to a minimum reserve (can be less than 50bar/500psi). You retain the remaining 2/3rds of the LHS as a contingency reserve only. This meets the requirements of 'rule of thirds'.
To configure the regs for doubles, you need:
RHS cylinder: 1x 1st stage. 1x 2nd stage. 1x SPG. (+ 1x LPI if you have a double bladder or want LPI hose redundancy).
LHS cylinder 1x 1st stage. 1x 2nd stage. 1x SPG. 1x LPI.
It works very nicely if you configure it for long (5'-7') /short (22-24") hoses for the regs... and get shorter (24") SPG hoses also.
Here's how mine looks:
View attachment 114862[/QUOTE]
QUOTE=DevonDiver;6208298]Whilst not "wrong", the advice isn't optimal either.
Seek out a cheap 2st stage and an extra SPG... and you've got a fully functional set of indie-doubles. This'll bring lots of advantages; primarily that you'll have redundancy and surplus gas. I dive indie doubles all the time, including to teach many recreational dive courses. It's very convenient and provides a lot of options and safeguards.
Depending on your air consumption, you could still do two dives from the two tanks:
Dive 1. Breathe from the LHS tank, until you reach your reserve 50bar/500psi etc. RHS tank is for redundancy on that dive.
Dive 2. Breathe from the RHS tank, until you reach your reserve 50bar/500psi etc. LHS is for redundancy - you'll have the 'extra' reserve left from dive 1.
**That's kind what you were asking, but without the reg on the second tank, you'd lose the redundancy. This will also result in the tanks becoming 'imbalanced' as the drained tank gets more buoyant...and the untouched tank remains more negative. This can screw with your trim (and, hence, comfort) in the water.
Alternatively, you could 'balance' the tanks over 2 dives:
Dive 1. Alternate the tanks, breathing a set amount (i.e. 35bar/500psi) from each, before changing... and repeat.
Dive 2. Continue that process.
Lastly, you can utilise both tanks for single, longer/deeper dives:
Breath 1/3rd of the RHS tank. Switch to the LHS tank and breathe 1/3rd of that. Return to the RHS tank and breath that down to a minimum reserve (can be less than 50bar/500psi). You retain the remaining 2/3rds of the LHS as a contingency reserve only. This meets the requirements of 'rule of thirds'.
To configure the regs for doubles, you need:
RHS cylinder: 1x 1st stage. 1x 2nd stage. 1x SPG. (+ 1x LPI if you have a double bladder or want LPI hose redundancy).
LHS cylinder 1x 1st stage. 1x 2nd stage. 1x SPG. 1x LPI.
It works very nicely if you configure it for long (5'-7') /short (22-24") hoses for the regs... and get shorter (24") SPG hoses also.
Here's how mine looks:
View attachment 114862[/QUOTE]