Regulator Configuration For Sidemount Diving – Another Hose Routing Option [Video] | Stephan Fehringer | Dive Instructor
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Regulator Configuration For Sidemount Diving – Another Hose Routing Option [Video]

sidemount tanks with two longhoses on it

Regulator Configuration For Sidemount Diving – Another Hose Routing Option [Video]

Divers who want to switch to sidemount diving have to make their decision which sidemount system or sidemount harness they should take. Then it comes to tanks and how to rig them perfectly, followed by the question about regs. This is what I want to talk about in this thread. But, there is no general answer to all that points at all.

How to setup sidemount regulators was, and still is an interesting advanced topic on sidemount configuration. Actually, there is a huge discussion going on regarding the “right” hose configuration for sidemount diving. It all started with a recommendation from Achim Schlöffel for ISE (Inner Space Explorers) sidemount dive courses. It was like a BOOM.  The ongoing discussion on the ISE´s Facebook page went viral, but in my opinion in a wrong direction and for some times also off topic. So I decided not to add anything onto this, however it´s time to get open minded, I think.

This text about sidemount regulator configurations should show you just another option. It may help you to see it from a different perspective and is NOT what I teach on my ISE courses!!


First things first.


I am diving the whole year around in both, warm and cold waters and in different environments like wrecks or caves. For me it is not important what kind of system I use, either backmount, sidemount system or rebreather, my approach is that different dives need different equipment. So I use a backmounted single tank for shallow dives far off any decompression obligation, double tanks (sidemount or backmount) for nitrox and trimix dives with max. two deco stages. For deeper dives and also for long dives I use a rebreather.


“Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth.” (Marcus Aurelius)


Playing around with different systems to learn about their advantages and more important their disadvantages is absolute essential for me. “What would happen when…” is the common question connecting all different systems together. During my dive courses, I never taught any strict way how to do things. Every diver and particularly diving instructors should think about the why and how. We should not simply copy a system or setup what we get taught or have read somewhere.


The worst thing happening on a dive is when someone run out of gas.


donating gas from the left tank in out of air situation

OOG – donating gas from the left tank

Never flouting the safety rules we all should end up at the same- or not!? For those who are trained on backmounted twinsets will already know: Deploy the regulator you breathe from, which is usually the longhose or your deco gas. Deploying the reg you breathe from is crucial, not only in the DIR community. First, this regulator is definitely working. Second, you breathe the right gas, so you donate the right gas. This is the golden rule, invented by DIR divers long time ago and maximizing the safety on every open circuit configuration.

On sidemount diving it is not so easy. Some people have a short and a long-hose on their tanks which is in general a good idea because of the benefits of having a long hose, specially in overhead environment. With this short/long hose sidemount system configuration you always deploy the long-hose because the short hose is attached with a necklace and can not get removed quickly. On a sidemount system you change the regulators regularly so the deployed long-hose is most probably working.


But honestly, probably working is not definitely working!


regular change of the regulators

regular change of the regulators

Try to imagine what will happen when you deploy a not working regulator to an out of gas diver. His eyes will become bigger and then he will grab your reg without asking you. You think that´s funny? You think it´s easy to handle such a situation? You can try it, but most probably only once!

The initial idea for diving a sidemount system was the ability do remove the tanks from your body to pass restrictions. This require the weights to be on the diver and the usage of neutral buoyant tanks to stay in position. In the unlikely case of an OOG situation it is easy just to pass one tank after granting the gas supply. Running out of gas on a double tank configuration, either sidemount or backmount, happens very rarely and there must have been some other unfixed problems before.

But there is also a second side of the medal. You give half of your gas away. This is not an excuse! Imagine the opposite way around. As long as you have done an accurate gas calculation this should not be a problem at all.

So why using a long-hose on sidemount then?


difficult hose routing- not streamlined from the right side, tried something new on the left tank

difficult hose routing- not streamlined from the right side, tried something new on the left tank

There might be some situations where it is appropriate to use the longhose to make it more comfortable instead of passing a tank. For example you are right before to change to another gas or in front of an restriction. Exchanging the tanks can also be a solution and then you do not need the longhose anymore.

So why not taking two short hoses on a sidemount system?

Routing a 1 meter hose streamlined can be very tricky. I know from myself and a lot of other sidemount divers, specially on the left tank when you breathe from it, it is almost impossible to route the hose streamlined. When using a turret on the first stages then a hose with less than 70 cm is long enough to breathe comfortably from it and it is routed streamlined without any unnecessary wide bends. On the picture on the left I used a black 90 cm hose and a yellow 100 cm hose. The yellow one I tried to fix on the tank to get it tight-fitted. But due the tank´s neck it does not hold good. Using two 70 cm hoses can force problems when donating them…

There are many pros and cons, but giving away the advantage of a longhose by using two (bad routed) short hoses can not be the perfect solution for proper sidemount diving.


Using two longhoses on sidemount diving!?


Let me point out some things using two long-hoses without a necklace. This sidemount hose configuration gives you maximum flexibility. Let´s see the facts:

  • You always can deploy the regulator from which you are actually breathing from.
  • There are not more weak points compared to other configurations.
  • You can benefit from having a longhose.
  • The long-hoses are tight routed onto the tanks, it is easy to adjust their length to your size and they are easy to deploy.
  • Same OOG procedure on both sides.
  • With a doublender or a boltsnap attached to both regulators they can be stored perfectly streamlined when not in use.
  • Using two different mouthpieces (or simply make a little cut in one) make it easy to remind from which side you are currently breathing from without touching it in case of a free-flowing regulator or any other malfunction in your system. Different boltsnaps on them can work as well.
  • No need to unclip the regulator in an OOG situation.
  • You do not need to pass your tank if you really worry about your own gas calculation.


adjusting the hose length on the left tank

adjusting the hose length on the left tank

sidemount tanks with two longhoses on it

sidemount tanks with two longhoses on it

So why not using two longhoses for sidemount diving?!


I am always trying to avoid weak points and unnecessary dive gear on every diving system I use. But on sidemount hose configuration, to say the truth, I did not find some reasons why not using a longhose on both cylinders. There are not more o-rings, its not more complex, regular regulator changing is very easy and quick,… it´s just a bit more streamlined and safely stored breathing-hose which gives you more possibilities in the unlikely case of any OOG situation on your dives.

Here is the video I made to show you an example of this sidemount hose configuration in action under water.


If you can not play the video from here, try this link.


This should show, that there are other ways to do it. So think yourself about it and build your own opinion. I´m always open for new ways and surely you´ll have some suggestions on this. I´m looking forward to your comments!


Always stay open minded!



  • Tóvári Sándor
    Tóvári Sándor
    Posted at 14:14h, 23 August Reply

    Nice article. Gonna try out soon 😉 safe dives!

  • Mike van Splunteren
    Mike van Splunteren
    Posted at 14:35h, 23 August Reply

    I think it is not about better or worse, I think it depends on from where you come.

  • Anton van Rosmalen
    Anton van Rosmalen
    Posted at 14:58h, 23 August Reply

    People that are looking for the “one and only” SM configuration, are missing the point of SM.

  • Anton van Rosmalen
    Anton van Rosmalen
    Posted at 15:05h, 23 August Reply

    Two longhoses sucks by the way, they get entangled all the time making it hard to donate anything.

    Personally I think the ability to donate is overrated on SM. In which realistic scenario could a SM diver go fully out of gas?

    • Anton van Rosmalen
      Anton van Rosmalen
      Posted at 16:25h, 23 August Reply

      I see two scenarios for a longhose: steel tanks that cannot be donated since they are part of the weighting system and mixed teams.

    • Mike van Splunteren
      Mike van Splunteren
      Posted at 17:27h, 23 August Reply

      Anton van Rosmalen, you probably know this out of experience, have you guys been using 2 longhoses? I have never tried that yet.

    • Anton van Rosmalen
      Anton van Rosmalen
      Posted at 17:30h, 23 August Reply

      We tested it years ago. I thought it really, really sucked. The problem is that both hoses are clipped off. You don;t know which is which and each tank requires a different move when clipping and unclipping in order to prevent twisting the hoses. During a dive, I want to focus on the dive, not on distinguishing which hose is which.

      Try it, you will find out immediately what I mean.

    • Mike van Splunteren
      Mike van Splunteren
      Posted at 17:31h, 23 August Reply

      Anton van Rosmalen, one big clipping/unclipping party…;-)

    • Anton van Rosmalen
      Anton van Rosmalen
      Posted at 17:31h, 23 August Reply

      Though I understand the reasoning behind it, it just creates more problems than it solves.

    • Stephan Fehringer
      Stephan Fehringer
      Posted at 18:39h, 23 August Reply

      see in the video: left hose always goes over right hose. On a shutdown you need to know from which side you breathe from anyway.

    • Anton van Rosmalen
      Anton van Rosmalen
      Posted at 21:15h, 23 August Reply

      I’m sure that statement really makes sense while sitting behind your computer.

    • Mark Rowe
      Mark Rowe
      Posted at 23:30h, 23 August Reply

      Seen two 5ft hoses Mike, worked ok. Again practice.

  • Ashley Hiscock
    Ashley Hiscock
    Posted at 18:05h, 23 August Reply

    Why do you need a long hose at all?

    You’re adding complication to an already redundant system.

  • Stephan Fehringer
    Stephan Fehringer
    Posted at 18:46h, 23 August Reply

    its not about the longhose, the point is that it is very hard for small divers to route a 100cm hose close to the body. using a shorter hose could force problems on OOG situations. So the whole thing ended up with two longhoses for routing and you do not need to use its whole length, but you can. The consideration was to find a solution for donating the gas you breathe from.

  • Malcolm Smith
    Malcolm Smith
    Posted at 18:47h, 23 August Reply

    I use one on my right cylinder purely to route the reg comfortably round the back of my neck to approach from the right. It’s an old apex 50, will only approach from the right and it’s all I’ve got : ) I have a pony length goes on the left cylinder also round the back of my neck to approach from the right. It’s a pain if you’re carrying any distance though!

  • Ashley Hiscock
    Ashley Hiscock
    Posted at 18:54h, 23 August Reply

    I use two 100cm hoses, they both sit behind my head and feed nice into my gob.

    Smaller diver? Use smaller hoses?

    Saying “oh, well this 100cm hose is clearly too long for a shorter diver, so everyone will use 210cm hoses” is ridiculous.

    Problems OOG? You’ve got another bottle, right there, next to you. Just swap regs!

  • Jason Renoux
    Jason Renoux
    Posted at 19:18h, 23 August Reply

    Is my hose shorter (or in that case, longer…) than mine??

    The reasoning behind the longhose/shorthose necklace is that “most” sidemount divers come from a backmount background, therefore the transition is already (if not pretty logical) in the muscle memory.
    Finding the crack in the system has its pros but you’ve got to justify the why’s you’re changing something that is already working…
    If you are smart and/or properly train in the voodoo craft that is sidemount, you know to balance the gas in your tanks and have sound gas management system. So for you or your (sidemount) teammates to run out of gas are very very slim but ok, shit happens… You’ve got a second tank, so here you go. Between sidemount divers, there should never be a need for gas sharing.
    Now, in a mixed team, you (the sidemount extraterrestrial diver) have a duty of ignorance: do a proper pre-dive check and S drill, during which you do a complete gas sharing drill. It may take a bit longer than the backmount divers but a good habit to get into.
    Remember, you are a safe, sound and caring sidemount diver, I couldn’t tell so much about the others… 😂 and so, you switch regulator very often to keep your tanks super trimmed. Telling this to your backmount Muppet..heu..meant “friend”, you tell them that 50% of the time, the longhose is clipped to the right shoulder D-ring, with a brake-away clip…for a reason.

    So as far as to use “the crack in the sidemount configuration” by saying ‘ah but if you don’t give the regulator you’re breathing from, equals to an attempted murder…or something equally unethical, is in my taste and many other sidemount instructors, very far fetched, if not unnecessary bitchy. But if you want to go this way, and leurre unconscious and incompetent divers into your “new testament”, go forth and I wish you to prosper.
    For the rest of us, we stick with what we know works.

    Dive safe and take care down there.

  • Mike van Splunteren
    Mike van Splunteren
    Posted at 19:48h, 23 August Reply

    Jason Renoux, hey man ! you just! …what is it that you stick to? because what I see, and what I have been taught, and what gets to me from far away…;-) is very different to what you might stick to. I see, 2 shorthoses, I see regulators from the right from the left, longhose on the left cylinder/on the right cylinder, I have even noticed yes yes….3 regulators on 2 cylinders and the list goes oooooon..We have talked about it many times, I agree with you, of course, the Longose isn’t gonna kill everyone, however, imho, there is a clear need for a clear description of what that modern sidemount system (that I teach as well) is. Go mountain climbing and you will find your knots…go rafting, you will find the how and what…go diving…and do what everrrrrrr?..that’s not the best way to create safe divers. What do you think?

  • Steve Davis
    Steve Davis
    Posted at 20:36h, 23 August Reply

    Stephan, you and I have dived together a lot in Gozo. It has always been safe, well executed and a pleasure. I love your approach and there is logic in the two long hose idea. There is also logic in two 100cm and also the short hose long hose configuration. So what is best? As you quoted this is all opinion and perspective… so here is mine :). Regarding the hose and cylinder discussions started by Achim’s video, a lot of the points of view draw on assumptions and then follow a path from that point. Case in point is DIR, “donate what you breathe”. There is logic there in not stressing out the OOA diver but in backmount once I donate, I then go to a backup reg that I haven’t breathed since I checked it on the surface… you make the point…”probably working but not definitely” and definitely more of a risk here than in sidemount where worst case, I have breathed it only a few minutes ago! In the event it is not working we now have two stressed divers… Doing it Right… I am not so sure. So, I have been running a straw poll of Technical Divers and Instructors in Gozo. I ask them… you are in sidemount and have a reg failure/gas issue on the reg/cylinder you are breathing… what will you do? In every case they have answered… “I switch to another reg”. In no case do they go to their buddy for gas as their first corrective action. They will certainly alert him/her that they have an issue and absolutely call the dive. Maybe somewhere before the exit they have to share gas but not yet. This is why we have redundancy – to be initially self-sufficient. In this circumstance, they have time to check all of their gear is working and see what they are up against. Same scenario during deco… my deco gas is gone… do I go to my buddy for his? No, my first action is to switch to another of my regulators/gases – bottom or travel. Then I alert my buddy and we figure a plan. This may well involve me taking my buddy’s deco reg and AL cylinder but I see no circumstance where we need to hand off a primary or secondary steel cylinder. I have trained hard for some years now in Sidemount using a short and long hose. Jason Renoux started me on this path. It works, really well!! Tom Steiner has furthered this to Trimix and up to two deco cylinders… it still works, really well!! Is it the best configuration? I think so but I am open to others doing it a different way and can definitely cope with diving in mixed teams provided they don’t expect me to be giving away my primary or secondary cylinder. Truth is – there is no need due to my long hose that I have just breathed and if necessary will breakaway from its clip and have it in your eyeline just as fast as pulling it from my mouth and switching to another reg. Bottom line there is logic in all of this and we each have to choose what is best for us and our diving. We then choose to dive with team mates that we have confidence in, and have confidence in us. What is wrong… is to say someone else’s considered and proven configuration is wrong… and that is where I take issue with Achim’s video!

    • Jason Renoux
      Jason Renoux
      Posted at 05:20h, 24 August Reply

      I would add that the way you have been taught Steve, is what is taught in Mexico and in many parts of the world too. This sidemount regulator configuration has been established as a standard and it works. Thousands of sidemount dives per year and no one has died. On top of that, diving in caves that are very complex and offer many restrictions possibilities to put at test the system.

    • Stephan Fehringer
      Stephan Fehringer
      Posted at 07:22h, 24 August Reply

      the long/short hose config is not wrong. If the short one is quickly removable from the necklace- than it does what I want from it. Give what you breathe. Another solution!

    • Jason Renoux
      Jason Renoux
      Posted at 08:32h, 24 August Reply

      “if the short one is quickly removable from the necklace then it does what I want from it”
      What is it that you don’t understand in sidemount Stephan?

    • Steve Davis
      Steve Davis
      Posted at 08:47h, 24 August Reply

      Jason Renoux If I may… Stephan understands and dives sidemount fine. He is a ISE Instructor so is set on the doctrine of “donate what you breathe”. The problem from “our perspective” is the primary is bungeed for a reason and we don’t want to remove it. The long hose we donate solves the problem and from our perspective also solves the… “is it working” problem i.e. we just breathed it. In sidemount it is far more reliable than the Backmount equivalent on which the DIR “donate what you breathe” doctrine was born. Would it be better to be able to donate either reg in sidemount? Maybe but then we lose the benefits of having a bungeed reg right there under our chin. I come back to my earlier comments that this all tries to solve a problem that in my opinion is not that prevalent i.e. a Sidemount OOA where all of my redundancy has failed. Can happen and all of the systems discussed can address this problem of donating gas to our unfortunate team mate.

    • Stephan Fehringer
      Stephan Fehringer
      Posted at 09:22h, 24 August Reply

      you may Steve.
      I dive mostly long/short as it is common and I like this config. “give what you breathe” get easy done with a breakable necklace which I always had. A bungee without knots fixed to the mouthpiece.
      “old” DIR ideas may sound religious, but it was a big step forward on safety at that time. Now more and more agencies pick out some pieces of it- late but they do…
      I can´t understand why “give what you breathe” is so bad for some divers. It is a little improvement on safety – which is always good I think- and can be easily done by removing a knot on the necklace (thats one solution). imho its just because “I´ve always done it in my way” – so I do not even think about…
      Sorry guys don´t feel attacked!! But only because the majority does it, does not mean that this is perfect and nothing to improve anymore.

    • InnerSpace Explorers
      InnerSpace Explorers
      Posted at 10:17h, 24 August Reply

      history is made by the few who did different and tried to improve! They where never popular at the time but became standards to follow in the books and now the net! Otherwise we would be still hunting deer with a speer and chasing women by the smell! LOL

    • Steve Davis
      Steve Davis
      Posted at 11:16h, 24 August Reply

      InnerSpace Explorers I guess, but there have also been plenty of missteps along the way, purported innovations that are really driven by dogma and of course adages like… “if it ain’t broke, don’t fix it”. I like the search for improvement so if that is truly the philosophy (and the video was more dogma) then bring it on. I look forward to the advances that might come in the future.

    • Jason Renoux
      Jason Renoux
      Posted at 12:08h, 24 August Reply

      That’s what it is about then… It makes more sense 😎

  • David Pearce
    David Pearce
    Posted at 22:13h, 23 August Reply

    My two cents worth – I learnt sidemount from Steve Davis, so my views are influenced by his, but one additional point I have found is that I currently have to dive a lot with back mount divers. Using the long-hose/short hose on a necklace config means that my hoses are routed around my neck almost exactly the same as a DIR back mount diver. This means that it is easy to explain to a back mount buddy what is going to happen in a donation situation, and that the way I present my long hose to a team member requiring a share is exactly the same as I would present it on back mount, and the way we would then exit is also the same. I’ve followed the other developments in sidemount hose configuration with interest, and I don’t think most of them are ‘wrong’ per se, but in my situation I think the long/short hose config is the most common sense one, and least likely to result in confusion if I have to share with a team member who is not on sidemount.

  • Bent Hansen
    Posted at 16:19h, 25 August Reply

    Great article! Steve Davis is making very good points, IMHO.
    People are trying to force DIR principles onto SM, that’s a mistake as far as I’m concernd.

  • Bent Hansen
    Posted at 00:52h, 26 August Reply

    BWT: Some of you guys totally should have posted that stuff on the fb thread (i assume you guys are ISE too). Don’t let the B-Team run the show on FB, 🙂

  • Benedek Hovanyi
    Posted at 01:34h, 29 January Reply

    Two things comes to my mind:

    1. Why not use 2 longhoses, but setup one of them as a short hose, with a brakeaway nacklace and the longhose tucked away.
    And pretend that it is a short hose, untill it’s needed by somebody. 🙂
    What could be the downside ?

    2. In a mixed team, (which is reality for me on holidays) what is the safest config?
    – 1 cylinder with the traditional 2 regs (yellow octo) setup?
    — In this case no confusion for the donor or for the OOG diver?
    – 2 cylinders with 2 separate longhoses
    — and use a yellow reg (perhaps with yellow hose also on one of the cylinders) to signal correctly to the other divers, who are not familiar to this kind of setup.

    Most fresh OW/AOW (PADI) divers are trained to go for the yellow octo in an OOG.
    Would it not be beneficial for all parties, in all kind of diving, to have a yellow reg, which is ment to be donated?
    Most GUE/DIR divers have all black regs, as they always have.

    Best regards //Benci

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