LP Hose Length for Chest Mount Regulator ?

[Bryan]

Since you can easily chest mount your regulator now I have had a few requests for LP hoses with 3/8" male fittings on each end to connect 1st stage to hookah port adaptor. It's no problem getting them made up but I'm trying to get an idea of what length is going to work best for most divers? Thinking somewhere around 29" should work? Any advice is appreciated since they will be custom hoses and can't be returned.

[captain]

Instead of getting hoses made what about an adapter with 3/8 on one end and a standard 2nd stage regulator connection on the other. That way any 2nd stage hose would be useable and it would swivel to keep out any tendency to kink.

[Bryan]

Great idea! 3/8"-24 male to 9/16"-18 male low pressure adaptor.

Golem Gear sells them cheaper than my current source can get them to me...Here is the link. I'll keep searching and try and stock some in the store soon.

http://www.golemgear.com/p-305-adapter- ... ssure.aspx

Thank you Tom!

[gj1963]

Great idea Tom - Thanks for that... I had not thought of the need for it to swivel.

[sthtxdiver]

can anybody post some pic of a chest mounted rig ?? thanx in advanced best

[luis]

Great idea! 3/8"-24 male to 9/16"-18 male low pressure adaptor.

Golem Gear sells them cheaper than my current source can get them to me...Here is the link. I'll keep searching and try and stock some in the store soon.

http://www.golemgear.com/p-305-adapter- ... ssure.aspx

Thank you Tom!

Using this solution also allows you to use an in-line shut-off valve like this.
http://www.golemgear.com/p-249-isolatio ... -1-od.aspx

The shut-off valve would take care of any free flow when the mouthpiece is out of your mouth.


If you do use a shut-off valve, you do need to make sure there is another second stage or a pressure relief valve in the first stage.

Here is a pressure relieve valve:
http://www.golemgear.com/p-157-over-pre ... or-38.aspx

[gj1963]

Thanks for the idea on the shut off valve. Here is my setup so far. Waiting on adapter now. Rebuilt Conshelf first and a DA that ironically had the nicest near perfect HP nozzle I had seen.

[luis]

I may dive this tomorrow.
It is a chest mounted HPR in a plastic case…

When and Aqua Master main body is mounted in a plastic case, the yoke is not centered with the case, but in this case there is no yoke.

The contact point of the HPR levers are not on the center of the diaphragm, but they are close enough to work. I had to bend the lever some in order to raise them.

Notice the shot-off valve and 90 degree swivel in the LP supply line.

I attached a 3/4” strap with snap buckle using the closure screws on the case. I am going to use the strap to attach the regulator to the shoulder straps of my tank back-plate harness.

The plastic case should be very comfortable on my chest.
You may notice that I reversed the angle of the horns.

Maybe I will have some pictures of the dive tomorrow.

[Drado]

Hmm, if you mounted a 3 port adaptor on hookah, and attached adaptors with shutoff valves to it (maybe a QD in somewhere) it would make for an interesting side-mount system...

[luis]

I have been looking at the QD for a side mount rig.
http://www.golemgear.com/c-29-quick-disconnects.aspx

I could again chest mount the regulator or I could wear it on my back like a hookah rig.

With a tank on each side I could switch between them with a quick disconnect (you could also use a switching block, but those are more expensive).


BTW, the side mounting is all very interesting, but for my normal diving it doesn’t really have a real practical application… I am personally not planning on taking any of this into a cave or similar…

[DaleC]

Looking forward to your results Luis.

I'm planning to chest mount my DAAM with this backpack using a leather pouch (like the shoulder pads) that clips into the D rings.



I've tried running my DAAM off the hookah and know it will work so my hurdles are mainly cosmetic. I think I want to strip a set of cans down to brass so they will eventually gain a patina to match the rest of the rig but wonder if there will be any issues down the road with doing that? I also don't like the waist belt and plan to replace it with something more fitting but haven't found a brass buckle I like so far.

I've kept tweaking the plywood plate (that image is prototype #3 of 4) but had an epiphany the other day. Why use plywood at all when I can run three brass flats horizontal to connect the shoulder hoop bolt holes, and bolt the tank band to the middle one. This also would suck the tank 1/2" closer to my back. So that's what I'm working on now. BTW, brass is very expensive

Here's a video of the backpack in action. I'm running a pony to power my drysuit and know I didn't route the hoses that well. It was something of an after thought.

http://www.youtube.com/watch?v=NsUSlert ... ature=plcp

[luis]

I did do a 55 minute dive yesterday with the chest mounted regulator. Water temperature was 58 degrees F. I was wearing a 7 mm two piece wet suit.

This is not my first chest mounted dive, but it was the longest.

The regulator worked well, but it was very odd having the bubbles around my chest. It wasn’t objectionable, just odd.

The positive pressure breathing is very different from what is encountered with a venturi induced positive pressure. With the venturi the positive pressure is only momentary during inhalation.

The positive pressure in this configuration is a constant steady state condition, similar to using an Interspiro/ AGA full-face mask and regulator (http://www.interspiro.com/diving.htm).

Actually, this configuration would probably work great with a full-face mask. The positive pressure would keep any water out of a full-face mask and would be comfortable held in place with the mask spider straps.

As you can see I used a conventional double hose mouthpiece. Due to the slight positive pressure you due have to hold the mouthpiece with you mouth. This is not much harder than holding a single hose regulator, but as compared to a normal double hose that just sits in your mouth, it was noticeable during a long dive.

With a conventional double hose mouthpiece it is probably best to keep a slight head down position during a long dive, in order to reduce the positive pressure in the mouthpiece.

I have a Cressi full face mask with a Hope Page mouthpiece I may try for something different.





This testing would be easier if I didn’t have all this neoprene and weights.

[DaleC]

I had a somewhat similar experience recently with my perhaps "too" finely tuned mistral. At the end of the dive with less than 300psi I was surface swimming (forwards) with the reg in my mouth and couldn't figure out why I was hyperventilating. I kept thinking "what is wrong with me?" until I realized it was the reg forcing air into my lungs as soon as I exhaled.

Do you think a detuned reg would perform better chest mounted for a traditional mouthpiece?

[gj1963]

Thank you for the informative write up Luis. Very interesting. Think the whole idea is neat if not the most practical. My own setup is slowly progressing.

[luis]

Do you think a detuned reg would perform better chest mounted for a traditional mouthpiece?

I think you should just try it and decide what you think.

Perception is a very personal thing… that is why I try to make instrumented measurements when ever possible. But I don’t have instruments that I can take in the water with me to measure inhalation pressures, etc.