Hose routing for backmount doubles?

[UTscuba]

Covid's pretty much killed my plans of starting tech classes this year.

I'd originally planned taking the class in back mount doubles, and have been building a pair of twin Al80 tanks and getting a bp/w set up in preparation. I was going to buy a new set of backmount regs, but I'm now thinking of temporarily re-configuring my sidemount regs and spending the summer learning to dive backmount doubles in my swimming pool.

But I can't find any good resource online showing hose routing. Can anyone point me towards anything either on youtube, or anywhere that'll get me started?

Thanks in advance

 

[ChuckP]

Here's an example - I'm not sure what the GUE Gods say is correct.

 

[ToneNQ]

SM regs are the neatest set up, the 5th port makes it much neater. I have both regs flat, facing in. Same routing as shown above, but I think I utilise my inflator hoses in reverse. I don't have the collision between the two 5th ports that the pictured Halcyon regs have.

I think the regs being flat gives much neater hose routes. Flat regs has the 5th port hoses coming straight out at the right level for my shoulders. It also keeps the AI transmitters located just offcentre from the tank neck; with the regs in that position I think the transmitters would be in the way during a valve drill. I use Miflex hoses, have a 90° elbow on my short hose and a 110° on the long hose. I have always run a 65cm HP hose to an SPG as per #5, just mine went straight down. Whatever you end up with, play with it until it suits you.

 

[UTscuba]

Here's an example - I'm not sure what the GUE Gods say is correct.

thank you, I'd never have guessed this orientation, nor would I have worked out using the 5th port for the backup reg.

How do the hoses continue around? Do they come under the arms and then wrap around the neck? And is the backup/short hose now truly a backup and only used in extremis?

And why only a single spg? What happens if that tank requires a shutdown and you're left breathing from the other?

 

[UTscuba]

I think the regs being flat gives much neater hose routes. Flat regs has the 5th port hoses coming straight out at the right level for my shoulders. It also keeps the AI transmitters located just offcentre from the tank neck; with the regs in that position I think the transmitters would be in the way during a valve drill.

Thanks, I'll try both ways. I have AI, so that's helpful

 

[ToneNQ]

thank you, I'd never have guessed this orientation, nor would I have worked out using the 5th port for the backup reg.

You would've once you started rigging it up, you're bending hoses and the 5th port is looking up at you yearning to be used.

How do the hoses continue around? Do they come under the arms and then wrap around the neck? And is the backup/short hose now truly a backup and only used in extremis?

The short hose comes from the left post and around the right side of your neck and the the 2nd stage on your necklace. A good test is to see how much head movement you have breathing from your short hose. Mine came with a 55cm hose (22") and it restricted being able to look left. A 90° elbow at the 2nd stage solved that and keeps the hose short. I use my secondary whenever I feel like it, ie changing stage regs and don't want to unclip your primary, use your secondary. This hose system is a primary donate, you donate the long hose on backgas. Tech diving is a many gas mixes with varying depth limits so you always donate the reg from your mouth.

#1 goes down the right side, gets tucked into your front waist band, up your left front, around your neck and clipped off on the right shoulder. #5 goes down to the left side waist D-ring. The others loop back up and come across your shoulders. The inflator hoses come over your left shoulder. Run those hoses, then put your secondary across the top and over your right shoulder, then loop your primary around your neck and clip it off.

And why only a single spg? What happens if that tank requires a shutdown and you're left breathing from the other?

You're ending the dive anyway. If you've isolated the manifold first in your V drill, the right tank will have enough air to get you home safely even if your left tank empties. Run two if you like but SPGs are heavy.

 

[UTscuba]

You would've once you started rigging it up, you're bending hoses and the 5th port is looking up at you yearning to be used.

[snip]

You're ending the dive anyway. If you've isolated the manifold first in your V drill, the right tank will have enough air to get you home safely even if your left tank empties. Run two if you like but SPGs are heavy.

Thank you! That is invaluable, and answered pretty much every question I had.

 

[Marie13]

Thanks, I'll try both ways. I have AI, so that's helpful

I have my transmitter coming off the right post. It’s on a 6” stainless steel braided HP hose. I have it tied to my long hose with a bit of bungee cord. Doesn’t flop all over the place. Works a charm. I saw someone else local do that and it’s worked the best for me. Tech instructor has no issue with it. The other diver I got the idea from is another student of his.

 

[UTscuba]

I have my transmitter coming off the right post. It’s on a 6” stainless steel braided HP hose. I have it tied to my long hose with a bit of bungee cord. Doesn’t flop all over the place. Works a charm. I saw someone else local do that and it’s worked the best for me. Tech instructor has no issue with it. The other diver I got the idea from is another student of his.

thanks, my spg's are on 6" hoses at the moment, so that's an easy thing to try

 

[Marie13]

thanks, my spg's are on 6" hoses at the moment, so that's an easy thing to try

This is what it looks like.