SM LP Inflator Hose Routing Question

[73diver]

I am committed to convert to sidemount. I immediately liked the features of the Hollis SMS75 so I purchased one. On the SMS75 the inflator can be attached to the left bottom of the wing or at the left shoulder. It came attached to the bottom. Mounted at the bottom, the inflator seemed to "always be in the way" of D-rings, SPG, etc. I noticed that "the pros" mounted the inflator over the shoulder. In addition, with the inflator bottom mounted, air is released from the shoulder dump-OPV. I like the convenience of releasing air using the shoulder dump-OPV. However, the surface of the OPV is semi spherical and the line makes a hard 90 degree angle. The OPV is situated under the left shoulder strap. With the OPV next to my suit under the shoulder strap I found that once activated the OPV remained open.

I decided to mount the inflator at the shoulder for the reasons above, which raises my question of hose routing. I have a 22" LP hose right now which is the wrong length. To keep hoses under control, I am considering routing the LP inflator hose up the inflator, over the shoulder and along the wing to around my left waist with a 30-36" hose. I could use the wing bungee to secure the hose. At the waist strap I propose to have a QD that connects to a 9" LP hose attached to the regulator. I know that adding another QD is adding another failure point but both QD's are within view and I have my drysuit inflator on the other regulator as a backup whether I am in drysuit or wetsuit.

What do you think?

Thanks,

Ken

 

[matt_w]

Just two points. I doubt you will find a "pro" consensus for where the inflator is mounted in sidemount. Up or down is a personal choice more than anything else.

On the hose length, I am not sure why you would want a 36" hose. A short hose from the reg under the shoulder strap and to the inflator is all you need. I have a friend that uses a short hose with an extender bent in a U on the inflator hose (semi permanently) to make it point downward. Then a short hose from the reg can go straight up to it.

I am not sure how much or what type of diving you do, but in my opinion, a 3 foot inflator hose you have to route up and then down the inflator every time you get in the water sounds like a pain. I am not sure what benefit it will provide.

 

[73diver]

a 3 foot inflator hose you have to route up and then down the inflator every time you get in the water sounds like a pain. I am not sure what benefit it will provide.

Thanks for the comments. I now realize that a picture or diagram would probably help my question. I was not proposing that every dive would involve routing a hose from the regulator under the wing over the shoulder through several bungees into the inflator QD. That would not be a convenient solution. The 3' hose (routed over the shoulder) would be always attached to the inflator and routed over the shoulder along the wing. The 3' hose rather than being attached directly to the regulator would end with a 3/8"-Male QD union. That Male-QD would be at the left waist. The left cylinder regulator would have a Female-QD on a 9" hose. The pre-dive connection would be between the 9" hose (Female-QD) on the left regulator and the Male-QD on the inflator hose near the left waist. There would be no hose routing involved. An aftermarket vendor sells this kit and refers to is as the "over the shoulder" hose routing for sidemount.

 

[decompression]

Personally, I favor the "more traditional" placement of lower left for the inflator. Deflating isn't much of an issue as there should be very little gas depending on your tanks/dive profile. If it's routed by bungee to the left D ring, towards the chest it shouldn't interfere with anything. Nice, tight and streamlined. No comment on the over shoulder placement as It's not one I've used proficiently enough to offer advice.


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[victorzamora]

I've used the "Over The Shoulder" routing before, and I tried like 8 different hose lengths before I gave up. Then I tried the bottom-up routing as is "stock" on the SMS75. It's MUCH better that way. Edd Sorenson, the designer of that rig and well known cave diver, routes it from the bottom-up on all of his rigs. It's interesting to me that the "successful" SM rigs all have an alternative to the "Over-the-shoulder" method. The Stealth, Razor, Hog, Halcyon, SMS75, and many more all have bottom-up type inflator routing. The "Pros" all seem to avoid over-the-shoulder as much as possible.

If you put your inflator in the middle of your chest, it's a neat, clean method of routing it that keeps everything out of the way. You also get a MUCH cleaner shot for your inflator hose. Also, you get a MUCH easier method of venting gas by going the way the SMS75 was intended.

 

[DevonDiver]

Mounted at the bottom, the inflator seemed to "always be in the way" of D-rings, SPG, etc.

A picture of your rig, as worn, would help. I just can't imagine how you are having a problem with this... you are routing it across the chest, to the opposite shoulder D-ring??

I noticed that "the pros" mounted the inflator over the shoulder.

I've never noticed that. Bottom-routing seems much more prevalent, especially given the popularity of rigs like the Razor, Stealth, Z-Trim etc.... Maybe it's a regional thing?

For me, there's never been a clean match up in hose routing to feed a top-mounted LPI. With a regulator 5th-Port, the hose routing is very deft to an across-the-chest, bottom mounted LPI.

In addition, with the inflator bottom mounted, air is released from the shoulder dump-OPV.

It's a flawed practice to try and tire-iron sidemount diving protocols to resemble back-mount. That's what I see with some of the rig designs hitting the market. I think they are meant to appeal to less experienced divers, who think "it's just like my back-mount, so it must be good"...

It's not hard to dump air from a bottom-mounted LPI. You'd only use that for initial descent from the surface anyway. Thereafter, you'd be using a lower pull-dump (as you would in a wing etc)... because you'd be in proper horizontal trim (wouldn't you?).

Decent sidemount training puts all those pieces in place.

The only people I see struggling with fundamental sidemount approaches are those that tried self-teaching, based on back-mount experience.... or those that elected to get tuition from a zero-to-hero, 3-day experience, band-wagon jumping sidemount 'instructor'.

I like the convenience of releasing air using the shoulder dump-OPV.

It's what some my call "an equipment solution to a skills problem".

....my question of hose routing. I have a 22" LP hose right now which is the wrong length. To keep hoses under control, I am considering routing the LP inflator hose up the inflator, over the shoulder and along the wing to around my left waist with a 30-36" hose.

So... in essence... your 'convenient' solution caused a host of follow-on problems, which are now very inconvenient to solve?

What do you think?

Take your chosen rig to a credible sidemount instructor, who has specific experience with that rig, and let them show you how to optimize it... in set-up and use. Good sidemount instructors spend a lot of time in rig set-up and/or customization.

 

[73diver]

It sounds like I may have ruffled some feathers with my questions. I took my training using a rented Nomad with side mounted inflator. My Hollis system is a little different and I'm getting used to it. The video to set up the Hollis, demonstrated attaching the inflator to the shoulder mounted location. The pros that made the video (cave diving instructors, I believe) are shown in the photo with the shoulder mounted inflator.

 

[DevonDiver]

It sounds like I may have ruffled some feathers with my questions.

I don't see any indication you've ruffled feathers; only that some people have expressed alternative opinions and/or offered some advice from their experience.

The pros that made the video (cave diving instructors, I believe) are shown in the photo with the shoulder mounted inflator.

If Hollis employ (or sponsor, or 'brand ambassador' etc...) instructors to make a product video, then it's unsurprising they promote the virtues of the equipment, configured as it is sold.

What you need to understand is that Hollis is one of several non-specialist sidemount manufacturers who have attempted to capitalize on the emerging recreational sidemount market by producing 'sport' or 'blue-water' versions of rigs. The main feature of which is top-mounted LPI. The notion being promoted is that low-mounted LPI is for overhead environment, wheras top-mounted is optimal for open-water diving. There is very little to support that notion, other than excusing recreational divers for having weak fundamental skills and poor diving ability; for instance, having to abandon proper horizontal trim and go vertical every time they need to dump air.

 

[victorzamora]

There are no ruffled feathers here, either. However, I will point out that the "Famous pro" you posted a picture of is the same one posted below. Big name instructor. He dives like this still, and teaches students to dive like this. I've had first and second hand experience with this instructor, his students, and the Instructor candidates he's created. BELIEVE ME when I say he is NOT the role model I recommend for any diver. Just something to think about.

 

[ajduplessis]

I was under the impression SM is all about steamlinig? Looking at the pic above I must be mistaken then? Who is the mutt in the pic? It is also clear that PADI and its marketing team have no idea what proper SM looks like.