Argonaut Mix-mount or Tri-mount… as opposed to side-mount

[Luis H]

Argonaut Mix-mount or Tri-mount… as opposed to side-mount

The new side mount configuration has been talked a lot for technical diving and I can see a few situations where it can be beneficial. I am not interested in getting in tight spaces, but I would be interested in getting qualified for tri-mix and renting a couple of tri-mix cylinders when traveling to some specific destination.

For some decompression (extended range) diving, I have used doubles with a center outlet and an alternate outlet for a completely redundant regulator, but I would never travel with my doubles unless I was driving somewhere and then I am not interested in oxygen cleaning my doubles for the rare occasion where I want tri-mix (using partial pressure blending).

So I set this up for some Mix-mount diving, as opposed to side mount diving.

The good news:
The hose routing and plumbing worked great. The regulator performance and usability of the connections worked fantastic. I have actually triple redundancy with this system, three potentially independent air sources.

I used the Argonaut Kraken as a manifold block to share the IP from three different first stages. The back-gas is only an AL30 and I set the IP on the Kraken t 110 PSI. The IP on the two Conshelfs is set at 135 psi. Therefore, as long as the shut-off barrel valves are open on either side mount cylinder, the back-gas will not be touched and it will be an extra gas reserve.

There are quick disconnect with shut-off valves on each of the side mount cylinders regulators. I can isolate all three air sources and each one has an independent regulator.

The not so good news (well maybe not so bad):
This was my first in the water test day so my side cylinders position need some adjustment. They are too far forward and dangling too much. They were somewhat clumsy in this position. I also need to adjust my back harness a bit. It is going to take at least one more dive(or two) to get the kit all dialed in.

Using a drysuit and heavy neoprene gloves makes the entire testing process a lot more clumsy.

The side cylinders that I am using are small (61 cuft at 3300 psi) but they are very heavy. I can shed about 8 pounds of lead by using these cylinders. Out of the water they are almost 30 lb each, plus the back-gas cylinder, regulators, and harness it all adds up.

In all, this is an interesting and versatile setup and I will be experimenting and developing it further, but it will never replace my simple steel 72 (or a rental AL80 in the Caribbean) on my VDH backplate with a simple wing.

Here are some pictures taken by John in Sebago lake.

The front of the tanks are too low. The bottom tank band needs to be close to the center of the cylinders and the valves need to be tucked under my arm.
I will fix that next test dive.

BTW, this was also a working dive. John and I installed a mooring ball. On my right hand is a mesh bag with tools and on my left hand is a lift bag.

 

[Akimbo]

Interesting, a schematic would help me understand it a lot if you could get one in a "postable" format. Did you mention first stage relief/over pressure valves to protect hoses isolated by valves and/or QDs? I can't tell from the photos if you can reach the QDs or not.

How would the Argonaut perform if you fed it with LP gas from the second stages? That might be an option for semi-independent doubles rather than triples. Just off-the-top brainstorming.

 

[Luis H]

There is no need for over pressure relief valves. All three first stages (the Argonaut and the two Conshelf) have a second stage attached to each one. The Argonaut always has its second stage and the two Conshelf have Scubapro 109 attached to each one. The LP hoses are all protected by at least one second stage at all times.

I am always breathing from the Argonaut second stage and under normal diving condition it is being fed the 135 psi IP from either or both Conshelf. I lowered the IP output on the Argonaut first stage down to 110 psi. As long as the Conshelf is feeding 135 psi, the back-gas is not touched.

In the last picture, hanging from the two side tanks, you can see the LP hoses with the “high flow” quick disconnect and barrel shut-off valves. All the LP hoses tie into the Argonaut LP ports (I had to add one LP “Y” adapter). The LP section of the Argonaut works as a LP manifold or LP block. It is actually a very simple setup.

The BC QD inflator and the drysuit inflator are also attached to the Argonaut (I am obviously not running an octopus out of the Argonaut). In an out of air situation, I could hand off one of the cylinders to a dive buddy if needed.

The performance of the Argonaut when it is fed LP air from the Conshelf is that same as always. IMHO, it is fantastic.

I will try to take some detail pictures of the pluming and post it later.

Doing semi independent doubles would be very easy. I like running the valves in front of me. It makes it a lot easier to reach, specially with a drysuit and gloves.

Thanks

 

[RainPilot]

If one of the sidemount hoses fails or the second stage freeflows, wouldn't it empty the opposite side through the Kraken?

Love the idea just curious about the redundancy of it all.

 

[Couv]

Luis,

Using the l/p section of a first stage as a manifold is sheer genius. One could plumb different gas bottles into it and use the tank valve or inline shut off valves eliminating a switching block.

Using differential Intermediate Pressure for prioritizing tank order is inspired. Some aircraft use a similar system with fuel boost pumps so the fuel load is used in the preferred sequence.

Well done my friend.

 

[Luis H]

If one of the sidemount hoses fails or the second stage freeflows, wouldn't it empty the opposite side through the Kraken?

Love the idea just curious about the redundancy of it all.

I have inline shut-off valves on both sides and they are both in front of me with easy reach. I can shut off any free flowing regulator and if I want to I can also disconnect. Even if the Argonaut itself malfunction I can disconnect both side regulators and breath directly out of either second stage.

I should point out that out of the three regulators the Argonaut will always be the most reliable. The first and second stage in the Argonaut are always dry. No contaminates (sand, salt water, etc.) can reach the mechanism. There are also a list of other reasons why the Argonaut is more reliable than the average regulator, but that is different subject (the average regulator can be very reliable anyway).

Some could argue that the additional LP hoses does add a couple of extra failing points, but IMO that is insignificant and I have means of isolating it if needed. As I mentioned, I have three potentially independent air sources. That is one more than the typical technical diving setup.


My biggest task right now is adjusting those two cylinders so that they look like the ones in your avatar.

 

[Akimbo]

... Some could argue that the additional LP hoses does add a couple of extra failing points, but IMO that is insignificant and I have means of isolating it if needed. As I mentioned, I have three potentially independent air sources. That is one more than the typical technical diving setup...

Life (and safety) is all about choosing the compromises that suck the least.

Edit: fix typo

 

[Luis H]

In a couple of places I miss spelled shut-off valves and spell check did not help me in this case. I tried to correct all the miss spell, but I can't change the OP.

Thanks to Couv for sending me an email pointing the mistake.

 

[Akimbo]

In a couple of places I miss spelled shut-off valves and spell check did not help me in this case. I tried to correct all the miss spell, but I can't change the OP...

You can usually edit your posts within the first 24 hours.

 

[Luis H]

I just did. It took a couple of tries with the original post. When I tried to edit it, the pictures were not showing at first. I agree:

Thanks