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kiwidiver
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First Name: jeremy
Location: Gosford, Australia

Double hose with modern gear + FX Aquamaster

Sun May 12, 2013 8:25 am

Aim: to integrate a double hose regulator into my existing gear configuration for everyday diving.

First of all a wee bit of an explanation of where I am coming from. Most of my diving these days consists of rocky shore dives mostly done solo or boat dives with the local dive shop usually with unknown buddy’s, so self-reliance has always been a big factor in my gear setups going back a long time. After messing around with big tanks, ponies, independent twins I have settled on my favourite tanks; two Faber steel 300 bar 7 litre tanks banded up with the usual modern isolating manifold. They give me heaps of air (~70cuft x 2 @ 300bar or ~55 cuft x 2 @ 232 bar ) nice and easy to handle on shore for those rocky entry’s, nice and balanced to dive with and have the ability to offer some redundancy. I was diving these tanks using an alloy backplate, wing and two Apeks regs. Now all was going well until my lifelong fascination with double hose regs finally got the better of me and I purchased a Pico DA, you know just to put in the display cabinet cuz its cool. Then I found VDH and discovered you can rebuild these things better than they ever were and realistically dive them, which I did with my DA along with its cousin my Spiro Mistral I was hooked.
Now as we all know the double hose doesn't always like to play nice with modern equipment, if you want to go all vintage then ok that’s great but it’s not for me, for solo diving in the ocean with modern steel tanks (negative) and using a modern (soft and compressible) wetsuit you need a wing, even though I don’t actually use it much. The best set up is the VDH back plate, with a small wing on a single tank, so I got one dived it works great. But I really wanted to use my little twin set with a double hose reg for every dive.

Problem 1; Manifold:
It has 300 bar DIN outlets on each side with the isolator in the middle so I would have to adapt a DH reg to DIN and mount it on one side, but then to get it into the correct position I would have to wear it down super low which then means the tanks bang my legs, I can't reach my valves and the reg is offset. Not good. I could go to an older style of manifold like the Sherwood but that would involve finding one and getting new bands made and forgoing the ability of 300 bar fills. Also I wanted to be able to get my tanks filled without grief, I get enough of that here just being a Kiwi let alone having weird tanks as well. I also didn't like the interference between the top of the wing and the DH reg when they are mounted on a central manifold.

Problem 2; back plate:
The modern backplate just doesn't work with the DH this has been discussed here heaps so no need to go into that, so it was either use no back plate just a harness like Luis uses or adapt the VDH back plate for a twin set.

Then it struck me what if I mount the DH reg directly to the back plate and remote feed it from another first stage then the manifold design would be immaterial, the regulator positioning would be independent of tank positioning meaning I could mount the tanks higher so I could reach the valves (bit of an issue for me as my shoulders suffer from a misspent youth crashing motorbikes) but still have the reg in the correct position, then the wing would then sit behind the DH. The independent first stage would then run the octi SPG and BCD feed.
HaHa so the fun begins, more to come.

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here are the tanks (ok they could do with a paint)

swimjim
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Re: Double hose with modern gear.

Sun May 12, 2013 8:55 am

Front mount?

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antique diver
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First Name: Bill
Location: North-Central Texas

Re: Double hose with modern gear.

Sun May 12, 2013 8:56 am

That sounds like a worthwhile project. Please post some photos of your results!
The older I get the better I was.

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Herman
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Re: Double hose with modern gear.

Sun May 12, 2013 9:45 am

A couple of thoughts. Removing the first stage and plugging it with Bryan's hooka plug seems to be in order, that would reduce the space needed for the regulator. Then I would drill and tap the adapter so I could scew it down to my plate. The biggest issue I see is finding room for the regulator in a spot close to the body....and I wonder about hose length, are they going to be long enough to get around all the tanks and manifold.....Personally, I would use a single tank and a pony, not quite as much gas but you can always surface and suface swim back if needs be.
Herman

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kiwidiver
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Joined: Thu Nov 29, 2012 9:24 pm
First Name: jeremy
Location: Gosford, Australia

Re: Double hose with modern gear.

Mon May 13, 2013 7:39 am

Project 1 making the remote feed reg:
I asked some advice from the board here; viewtopic.php?f=47&t=6876 and got some great info as usual from Luis and Herman, in the end I decided to go ahead and give it a go.
The build was super easy the DA body fits straight into Robs pre-cut cans, add the HPR and single stage diaphragm, remove the nozzle and plug it and you are good to go, almost.
The issues with the DA body and the FX cans are:
• The body is no longer offset so the second stage is further away from the horn which will affect the venturi
• For the same reason the leaver will not contact the diaphragm in the centre
• The DA body doesn’t protrude as far into the cans as it should
It took a lot of fiddling around with adjustments and testing in and out of the water but what I ended up with was:
• the HPR unscrewed enough for the venturi hole to have a clear path over the body ring.
• One washer added to the HPR to increase cracking effort.
• IP set to 10 BAR
• Both venturi bleed holes blocked by 50% (this for some reason gave a more stable effect than one completely blocked and one open)

It now cracks at about 0.5 inches and the venturi seems about right. For a comparison I put everything back into the DA cans and set it up as per Luis recommendations for a normal HPR installation and dove it then swapped it all back to the FX cans and jumped back in.
I am happy with how it performs in the water for now. Two issues I have noticed, there seems to be a bigger swing in cracking effort due to position in the water, this is something that Luis also mentioned when he tried the same setup as a chest mount. What I mean by this is imagine you have the identical set up, one in the DA cans and one in the FX both have the same WOB when horizontal in the water when you go head down the FX can setup will breath slightly harder than the DA can set up. when you go head up the FX will breath slightly easier than the DA can setup, this I am thinking is a result of the leavers not being centred, it is not a big issue for me at the moment so I will leave this issue for now. The other issue is that because the DA body doesn’t protrude into the cans enough the leavers aren’t as high as they should be I don’t think this is a big problem but it may be part of the performance swing issue, it also means that the venturi hole in the HPR doesn’t fire exactly down the middle of the horn, with that and the venturi outlet being a little further away from the horn makes me think that the venturi action isn’t as smooth as it should be. It can be made strong enough with both ports blocked it will out of control free flow. It works fine you can feel the venturi working but it doesn’t vent on inhalation it just feels a little rough like the flow coming out of the venturi hole is becoming a bit turbulent before it enters the horn, but it is ok for now a few more dives on it before I make any more changes.

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this is the first set up.


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The venturi only just peaks over the body ring i thought if i lined it up with a notch it would be ok but the venturi action was a bit unstable.

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Another shot with the HPR unscrewed a little.

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A bit better and the venturi action is more stable. Not perfect yet though.

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kiwidiver
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First Name: jeremy
Location: Gosford, Australia

Re: Double hose with modern gear.

Mon May 13, 2013 9:05 am

Project 2; Mounting:
As I have already stated I wanted the positioning if the reg to be independent of the tank positioning. To do this I decided to mount the reg directly to the plate, this is one of the primary reasons for using the FX cans as I couldn't think how to mount the DA cans without damaging them, also the tapered design of cans gives more clearance also I think they have a more modern look. So what I ended up doing is I removed the fins between the bottom two screws, replaced those screws with longer ones, drilled two holes through the plate and bolted it on using some rubber bushes. The whole reg has a lot of movement on the rubber bushes fore and aft which stops any pressure being transmitted to the reg. then it was a simple job of using some flush nuts to secure the plate to the band bolts then playing with the heights. Then add a first stage with a SPG and an octi and away you go. It works rather well, I was concerned that the reg stuck out a bit too far from the plate but in practice it is ok, you can actually feel the reg pressing between your shoulders and the whole thing is very solid. The big advantage is as I have already said you can have the tanks anywhere you want high or low and the reg stays put. Also with the wing behind the reg if you do need to add air at depth it is not pushing the reg away from your back, if anything it holds it in place. I have been diving it so far with just the one first stage but you can add another with the DH and SPG off one side and the octi and BCD feed off the other. All in all I am rather pleased with how it turned out I have done about 10 dives with it so far and it is a nice balanced set up. At this stage I don't know if it is worth developing it further other than just some more tweaking as I don't really want to do any major mods to the DA body. I have a couple of ideas that I may peruse using what I have learned to achieve what I want without the limitations the DA body presents. In the meantime, more diving to do.


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The flush nut thing of which the proper name escapes me.


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add a couple of notches and it can be screwed onto the band bolt using a washer, coin or a blunt point dive knife.

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Final set up using one first stage.


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luis
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Re: Double hose with modern gear.

Mon May 13, 2013 9:58 am

I like the set-up you are playing with. It has a lot of potentials. A very similar set up could be used with side mounted tanks (the latest rage in the tech dive industry) or even used with bottom mounted valves (for easier access).

Here is something I just posted in another thread were someone else is playing with Rob’s plastics cans:



Rob's plastic cans have a lot of potential uses. I have been experimenting with Rob’s plastic cans and the Argonaut.

Let me make it very clear: I am only using Rob’s cans as a test platform. Before anyone ask: the Argonaut will not be offered with modified Rob’s cans. The cans for the Argonauts will be a new design.

I have been experimenting with the geometry and the induced venturi flow. Let me just say that there are several variable that will affect venturi flow: flow geometry, flow velocity, gas density, etc. And stopping/ controlling the venturi flow is as important as initiating it.

When I have some time I will share some my observations.

For now I will probably continue more experiments using an old Phoenix in the modified Rob’s can. The US Divers type two stage regulators (Aqua Master, Royal Aqua Master, Phoenix RAM, and nor the Argonaut) are designed to be offset form the center by 0.3 inches.

I will have more information later.


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Luis

Buceador con escafandra autónoma clásica.

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kiwidiver
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First Name: jeremy
Location: Gosford, Australia

Re: Double hose with modern gear.

Mon May 13, 2013 8:00 pm

Cheers Luis, i am really looking forward to your results, like i said it's OK but it just doesn't feel quite right, and as you say where the venturi is concerned there is a lot going on. My original plan was to do this with a Mistral as i still prefer how my Spiro breathes but coming up with a low profile remote feed adapter to screw onto the nozzle was a bit too much as i don't have access to a lathe. So the Spiro is my goto reg for single tank dives. I have been mulling over in my weird little brain how adding a short nozzle to the second stage to make up the distance and height variation will affect things just for the sake of experimenting. in the meantime i am off to pick up a Healthways steel tank complete with a Scubastar reg and original harness attached i scored for 20 bucks.

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kiwidiver
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First Name: jeremy
Location: Gosford, Australia

Re: Double hose with modern gear.

Mon May 13, 2013 8:07 pm

Oh and i love the idea of upside down tanks, somthing i have wanted to do for ages. it would really spin out the locals. Divers over here are very set in their ways generally speaking and i have a weird pathological urge to do go against the norm, usually for no good reason and often to my detriment :wink: .

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kiwidiver
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Location: Gosford, Australia

Re: Double hose with modern gear.

Wed Jul 10, 2013 7:59 am

Well i got all inspired by Luis's pics of his experiments with the Argonaut and the FX cans, so decided to move forward on my DA/FX project. i was reluctant to make this step as it did involve cutting into the cans and i was a bit scared of cocking it up but in the end i decided to give it a crack. So what i ended up doing was to enlarge the hole in the can. Then i made an adapter plate out of some ABS. By mounting the adapter on the inside of the can i managed to increase the lever height relative to the diaphragm, get the venturi hole pointing down the center of the horn as well as the main aim which was to offset the body to the required .3 inches so that A; the venturi outlet is closer to the horn and B; the leavers contact the middle of the diaphragm. I have done a few dives with it now and it has made a huge difference. The WOB swings due to position are now not as severe and are now the same as what you expect from a normal DA or my Mistral for that matter, and the venturi action is a lot more predictable. i still have some fine tuning to do, the first couple of dives i had the cracking effort set too low so it was free flowing when i went even a little bit vertical. so i have added a couple of washers to the spring as i didn't want to lower the IP too much, the ip is set at 9bar currently and this fixed up the free flow. I also have one of the venturi adjust holes fully open and the other about a 1/4 blocked but it feels like it needs a little bit more venturi assist. having said that the last two dives were to 30m and i was very happy with the performance.
Luis i would love to hear more about your experiences with the Argonaut/Phoenix and the FX cans.


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kiwidiver
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Location: Gosford, Australia

Re: Double hose with modern gear.

Tue Sep 10, 2013 10:51 am

So I have done a few more dives and all is working well so I decided to make a better looking adapter plate, after some mucking around and testing I decided to cast it from epoxy and cast it in place rather than make a mould, here’s what I did;
Sealed the can on to a glass lid and blocked up the holes and gaps with plasticine. Made up a plug for where the body will go. Then greased it up with release agent.
Poured the resin. I used a casting resin mixed with a graphite extender and let it harden.

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Once it cured it pope out nice and easy then after a bit of sanding, shaping and polishing I ended up with a nice adapter plate that fits exactly.

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I needed to do some remedial work on the sealing surface for the body to get it smooth square and the correct thickness. Then I bonded the adapter into the can with a marine polyurethane sealant/adhesive.

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Now it looks a bit less homemade. It tunes up nice and weather permitting should get out to do some testing. I also now have a phoenix so I have the option of using it with a single tank too.
All in all the project is turning out nicely and I have a nice performing reg with the performance additions of the HPR and the DBE with a contemporary look that I can use without worrying about messing up the nice original cans. And since no major mods have been done it can be returned easily to its original state.
After a few more dives and some fine tuning I want to look closer at the venturi as I feel there can be some improvements made there.





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1969ivan1
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Re: Double hose with modern gear + FX Aquamaster

Tue Oct 15, 2013 9:20 pm

That looks like it belongs there. I love to see peoples projects and ideas come together.

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