Doubles Hose Routing: What Goes on Each Post and Why

On DIR backmount doubles, the right post feeds the long-hose primary and the wing inflator. The left post feeds the necklace backup, the pressure gauge and, if you dive dry, the drysuit inflator. The split is deliberate. Lose either post and you still have a regulator to breathe and a way to add buoyancy.

By Jeremiah Gardner · Last reviewed October 27, 2026

You're kitting up on the boat. Your doubles sit on the bench next to your teammate's. Picture their left post. You already know what's on it.

You know without looking.

That's the whole idea. A doubles rig can be plumbed a hundred ways, and most of them work fine. Right up until something fails. Then the only layout that matters is the one you, and your team, can work with your eyes closed.

What goes on each post?

Post	Hose	Where it goes
Right	Long-hose primary (7 ft)	Down your right side, across your chest, around your neck
Right	Wing inflator	To the inflator on your left shoulder
Left	Necklace backup	To the bungee necklace under your chin
Left	Pressure gauge	Down your left side to the left hip D-ring
Left	Drysuit inflator	Under your left arm to the suit valve

Two posts. Five hoses. Nothing extra.

Why split it this way?

Here's the thing. Doubles aren't really about more gas. They're about options when something breaks.

Two cylinders, joined by an isolator manifold, each with its own first stage. If one side fails, you shut it down and keep breathing from the other while your team ends the dive. The layout decides what you still have when you do.

Lose the right post. Your long hose and wing inflator are gone. You breathe your backup, on the left. Your drysuit still takes gas from the left, and your wing still has its oral inflator.

Lose the left post. Your backup, gauge and suit inflation are gone. You still have your long hose to breathe and your wing to add lift.

Either way: one regulator to breathe, one way to add buoyancy. That's not an accident. It's the design.

What you do in each of those failures, in what order, is the valve drill, and that's learned in the water.

Why does everyone plumb it the same way?

Let's be honest. Most people don't build a messy rig on purpose. They build it one hose at a time, the way it fit that day.

The comfortable belief: it's my rig, so I'll set it up the way I like.

The truth: your rig is your team's rig too. When your teammate reaches for your left post in the dark, it had better be where theirs is.

The usual problems all break that rule: wing and drysuit on the same post, hoses that loop out past your outline, a long hose trapped under other gear, a gauge that dangles. Each one is a snag point or a failure that costs more than it should.

Can you name every hose?

Go look at your rig. Right post. Left post. Can you name every hose without looking? Can your teammate? Could you say exactly what you'd lose if either side shut down?

For how the long hose routes, read Long Hose Configuration. For the rest of the rig, read DIR Gear Configuration.

If the answer is "not yet," that's what the Doubles course is for. Bring your rig. We'll set it up right, with you.

Frequently asked questions

Which post does the long hose go on in doubles?

The right post. The long hose runs down your right side and comes into your mouth from the right, so it presents straight to a teammate when you donate it.

Why is the wing inflator on the right post?

It keeps the wing and the drysuit on different posts, so losing one post never takes away every way to add gas.

Where does the drysuit inflator go on doubles?

On the left post, unless you use a separate inflation bottle.

What hose lengths should I use on doubles?

The long hose is 7 feet, the same as on a single tank. The rest are fitted to you and your rig, and we set them up with you in the Doubles course.