One thing that I always seem to talk about when I dive with other people on twins is how we route our hoses trying to find the best configuration. Everyone seems to do it slightly different and I've spent a lot of time on mine getting the right layout and lengths. Instead of blindly assembling your regs take some time to talk to your Instructor and buddies to see how they route their hoses and don't be afraid to ask why all the time because often the answer is 'because that's how my Instructor did it'.
Training agencies around the world have spent decades assessing configurations and reasons behind them, but the most important factor is that you and your team is comfortable and confident in each others configuration. So use this as a starting point, reassess often with your team and only accept perfection.
- x2 2nd Stages
- x2 5 Port 1st Stages
- x1 210cm Reg Hose
- x1 60 -65cm Reg Hose
- x1 55cm LPI Hose
- x1 85-90cm LPI Hose
- x1 65cm HP Hose
- x1 Glass/Brass HP Gauge
- x1 75mm Boltsnap
- x1 120mm Boltsnap
- x1 Bungee Necklace 65cm
- Cave Line
LONG HOSE PRIMARY DONATE
I dive with a long 2.1m hose that comes off my right cylinder, down the length of the cylinder, under my right arm, under my knife, up the front of my body, over my left shoulder, around the back of my neck and in my mouth. Now that might sound complicated but it is very quick and easy to donate and you know it's functioning. I've only had to donate a few times in a real world situation but this is by far the most convenient configuration. The length gives flexibility so you don't have to dive side-by-side and wrapping it like this holds it close to your body while being quick release and deployment. It's vital that you don this hose last as any tangles can make out of air situations tricky with a 2nd stage trapped under another hose.
My alternate comes off my left cylinder, over my right cylinder onto a bungeed necklace so it's right where I need it in a scrape. It needs to be close to your body so it doesn't dangle but it needs to be mobile enough to be practical.
I then need a low pressure QD for my BCD and for my Drysuit, these are both buoyancy devices so I fit one to each cylinder for redundancy. My BCD hose comes over my left shoulder from my right cylinder and drysuit drops straight down from my left cylinder under my left arm close to the body.
My SPG comes off my left cylinder and down to my left hip, simple and effective.
With this setup a 5th port 1st stage, like a DST or Mk25, is neater so your hoses don't have to bend as much to get to where you need them and the LP hoses can route better down the side of your cylinders.
RIGHT 1ST STAGE
So my right 1st stage has my primary 2nd stage and my BCD hose only. These two are on my right post because if I swim forward in an overhead environment the valve handle will only be turned in an open position and I won't loose my primary gas and buoyancy supply.
LEFT 1ST STAGE
My left 1st stage is my redundancy package and SPG, my alternate air source and my drysuit hose come off the left cylinder with the SPG which sits neatly out of the way and is easily accessible even when my right hand is occupied.
My primary and BCD hose are fitted to my right post because in an overhead environment swimming forwards if the valve rolls on the surface it will roll in an open position so should never un-knowingly close (that's what my Instructor told me).
Everything has been made to be as simple and reliable as possible with minimal failure points and excess hose that can catch and snag but each is long enough to be comfortable and functional.
There are kits out there that give you a good starting point with dedicated 1st stages made for twins like the Tek3 and 25X Regs. Sidemount sets are also a good starting point but take your time and don't buy the first set you see, look around for the set you need.
How do you set up your twin Regs? Let me know in the comments below and help some divers new to Twins get some ideas for setting up their rigs.