Mounting plate for tank and pony bottle

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Cthippo

Contributor
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Location
Bellingham WA
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25 - 49
I've looked at the options for back mounting a pony bottle and I'm not thrilled with them.

My Current BP / W has a piece of C channel that the main tank straps onto, and of course no accommodation for a pony. Most of the pony systems I have seen either strap onto the main tank, or else attack to the main tank straps. I have yet to see a system where each tank is held independently with it's own straps and they can be easily removed and replaced without affecting the other tank. Some attempt and balancing them side to side would also be nice (i.e. main slightly off to one side and pony further to the other side).

Is anyone aware of a mounting system that allows main and pony to be removed without touching the other one? Maybe a piece of tee profile material mounted to the back plate with a set of straps on each side, or perhaps a W shaped plate that holds the tanks in the correct separation?
 
I'm a big fan of slinging pony tanks. This fulfills the requirement of being able to swap the main-tank, without touching the pony. You have full access to the tank at all times, and could even detach or re-attach it underwater, manipulate the valve, or hand it off.

You can also do a "sidemount" style, under your armpits, which is fairly streamlined. The way I often dive is side-mount, with an AL80 and AL19. Despite these tanks being completely different sizes, I never noticed any trim issues. The AL19 is used as purely-redundant, despite being mounted exactly how a side-mount tank is mounted. The AL19 is usually at about 2500 psi the whole dive and not used other than for practice and verifying function.

Some people also sling tanks diagonally across their chest. Perhaps a slight increase in drag, but it would be balanced left-to-right.

Another advantage of slinging is you can reduce the hose-routing hassles. Use a short-hose 9-inch on the SPG, ditch the BCD inflator (or use a short-hose for your dry-suit, if applicable), and all you really have is the regulator-hose, which you can tuck under bungies on the tank. I actually have a 7ft hose on mine, but it's almost no different than a short-hose, because it's all under the bungies.

(These are just alternative suggestions, I definitely understand if you wish to back-mount the pony).
 
I actually have a 7ft hose on mine, but it's almost no different than a short-hose, because it's all under the bungies.
You have a 7’ hose on your AL19 pony?
 
You have a 7’ hose on your AL19 pony?
Yes. Disclaimer that this is how I dive, and what works for me. This is not necessarily always the "proper" or "best" or "ideal" way that other people should dive.

I typically dive sidemount, and use the same regulators (2 complete sets, no octo), whether I'm doing real sidemount (2 full sized tanks), or my weird-lazy-sidemount (80cu + 19cu). While I mostly dive solo, my right-tank is always my donate-side, and I tell dive-buddies the green-hose regulator is the one to grab.

Anyway, I don't want to drive this thread too far off-topic, so this is just an idea to consider, but maybe or maybe not something OP would be interested in.

20220624_070721.jpg
 
You're close to describing Independant Doubles using dual cam band slots found on most plates.

Not exactly what you want, but the Trident Quick Draw mounts work well. Yes the pony is attached to the main tank strap, but the mount stays with the strap. Pull pins to remove/install pony when changing tanks.
Very simple and solid..love mine. You can slide it around a bit prior to strapping to find your favored spot. It is very snug fitting to the strap so does not move when strap is loose. Mine is close in to my side, inverted.
Only thing I changed was the pin cables. They kept coming undone, so used heavy mono and crimps to fix.
AQUTPB_ALL.jpg20220624_094521.jpg
 
I'm a big fan of carrying my pony on the front of my rig, rather than attached to the tank on my back. If I have an emergency & need to reach for the pony quickly, I want it in front of me, where I can clearly see everything & I can reach it easily.
 
I'm still thinking about this and i have come up with three possible solutions...

photo_2022-06-27_02-18-21.jpg
This is my setup, a Hollis backplate with a C45 wing. Nothing really special. The wing and tank holder mount to the back plate with two bolts, mounted in the center, top and bottom. They used wingnuts, which seems, well, nuts to me, and which I plan to replace with stainless locknuts.

These are the three options I am playing with for a tank holder. Again the goal is to secure mount both a main tank and a pony in such a way that either can be removed without having to touch the other. In addition, it is designed so that the mount can be shifted side to side to try and balance different sized and weight tanks. Tank straps are not shown in the drawings, but I'm sure you can add them in your imagination.

Option 1 uses a Tee profile. It would give a fair bit of support to both bottles and accommodate different diameters, but would have very little side to side travel. I am also concerned about the forces from the cam bands distorting the flanges of the plate.

Option 2 is a W shaped plate with horizontal slots for the mounting bolts, allowing some movement from side to side. This would be a very strong system since it would be made from a single piece of metal (probably stainless) but would create a limit on the diameter of tanks you could use and while it would have more adjustability side to side than option 1, it wouldn't be much more. This would also be a fairly heavy chunk of metal.

Option 3 is a fabricated rig with two pieces of channel stock joined by crossbars which could be slotted for the mounting bolts. This design is lighter than option 2, but probably less durable, while having some of the same issues with larger diameter tanks. It would also require a welding process versus bending plate,
Tank configurations.jpg
Obviously these are just concept art, not detailed drawings, but i'm soliciting thoughts on them. I can't imagine I am the first person to decide this was a big enough problem to be worth solving.
 
Obviously these are just concept art, not detailed drawings, but i'm soliciting thoughts on them. I can't imagine I am the first person to decide this was a big enough problem to be worth solving.

No you are not, but by the time you do that, you'll have up graded to doubles:wink:
I assume by the pictures you are offsetting the main tank?
Maybe instead of that.
make an offset channel that can bolt on. Like a drysuit argon bottle.... or make a heavier duty version of that mount
 
No you are not, but by the time you do that, you'll have up graded to doubles:wink:
I assume by the pictures you are offsetting the main tank?
Maybe instead of that.
make an offset channel that can bolt on. Like a drysuit argon bottle.... or make a heavier duty version of that mount
Or just carry it slung, perhaps with a bungee from the backplate and around the pony valve, and not have to faff with any of the above
 
Or just carry it slung, perhaps with a bungee from the backplate and around the pony valve, and not have to faff with any of the above
That's what I do.
I have length of 3/16 bungee from my backplate though my chest D ring, and back to the back plate, it stays there all the time, great for a pony or stowing a dpv that I am not using...
 

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