I wanted the safety of a pony bottle, but I could not find any
setup that fit my kind of diving. I'm a spearfishermen and a
lobster hunter. I'm frequently laying on the sand digging under
a rock hole to grab a bug with my arm. So any 2nd stage can't be
strapped by my stomach or it's going to get sand in it as I reach
way back into the hole, laying on my front and side.

I also already have my octo on a necklace to also keep
it out of the sand so putting another hose and 2nd stage up
there is just going to lead to confusion in a panic situation.

I needed to meet a couple of personal requirements.

1. Get me from 105 feet with without blowing my ascent rate indicator.
2. Give me 3 minutes to stop at 15 feet.
3. Must have air gauge on the pony since I'm already freaked out.
4. Very low psi air purge for end of dive dis-assembly so I don't have to refill pony
5. Must be able to hand-off to buddy.
6. Must be attached to my BC so I can easily go from tank to tank
7. It must be compact so I'll always use it. Not like a 19 cu ft tank.

All the mounts out there, just didn't work, so I rigged my own.
Here's my redneck version of a pony mount....

I started by looking for a backing plate that was plastic but
had some strength so not bend under the rubberbands and being
tossed in my dive bag week after week. I tried 5 gallon buckets,
flat hard plastics, and other things. But this item had the curvature,
thickness, size and strength to do the job. It's a sprinkler valve
bucket easily available at Home Depot or a hardware store.
The pictured one is green, but mines black.

I cut it about 3-3/4" wide and 9 inches tall. I tried
to include the 2 small stiffener ridges on the piece
and then cut right next to them and then all the way
to the top. This made the bottom a clean edge and the top
a clean edge that didn't have to be sanded.

I then cut four 2 inch slots on one side and 4 matching
2 inch slots opposite of them so you can thread
the elastic bands through. Here is a back side of the mount
and you can see the cuts that I made.

I bought a couple of feet of 2 inch elastic waist band
material from a fabric store. I then double wrapped/threaded
the elastic through the slots and hand sewed it on the backside
of the hard plastic. The relaxed diameter on the bands is
8". That's because the diameter on the 6cuft pony is 10 inches.
This allows enough grip as well as flexibility to slip the pony
out of the bands when under water and wet. Remember that the
water will act as a lubricant underwater to ease pulling it out.
At the same time it will act as friction when dry and you are doing
your giant strides for more grip.

No matter what you have to hand stitch the elastic after it is threaded onto
the backing play. The easiest way to do the elastic is to lay it straight
out on a table and measure it out. The first
measurement to mark with a pen or I used a white out pen, should be at
about 1 inch. That is so you have some material to start the stitching.

Then measure out another 8". That will give you the diameter of 8" relaxed.
Make a mark there. Then measure out another 8" and mark that, then add
another 1" for stitching room and finally cut it there. I would not cut all
four pieces at once. Do the first one, thread it and sew it. To thread it,
start from the back and feed all of it through the one slot until you are
just hanging on to that 1st one inch mark. Then take the long end that you
just threaded and thread it back into the 2nd slot. Match up your 1inch
mark, with your 1st 8" mark and hold it with your fingers. Then feed it
again into slot number 1, out the front and back into slot #2 and match up
your 2nd 8" mark with the other 2 marks in back. At the actual stitching
point you should be stitching 3 elastic layers together, but there will
still be just a doubled up band in the front. Look for any mistakes, then go
ahead and cut the other 2, NOT 3 remaining pieces. Remember that band number
3 is the outside band to accommodate the tank strap.

Band number 3 is the tank band. That is the one that will go on the outside
edges. To give it a lot of strength, cut those slots fairly wide apart, so
the tank has plenty of plastic to grab. This part of the plastic is what
will take all the weight of the pony bottle. Don't worry because that
plastic if pretty thick and sturdy, but it's best to do it right.
On the picture below you can see that the 3rd band from the bottom
does not loop behind the hard plastic, but instead wraps around the
outside edge. This is so that you have room to thread the tank
cam band through the hard plastic to mount the pony.

Still measure out the exact same measurements,
but instead of threading from the
back, this time you will start the threading from the front. When done,
again you will have a doubled up band and at the stitching point will be 3
layers of elastic to sew.

After you are done stitching all four elastic bands and trimming the excess
back, don't forget to singe/burn the ends to seal them off from fraying.

The next two pictures will show some other angles.

Make sure you take a small round file and knock down the edges to
smooth them out so they don't snag the soft elastic and fray it
from the stretching it will take.

I also drilled a small hole at the top of the hard plastic to
attach a thin bungie so that I could put a octo cover. This will
keep the mouth piece clear and when you pulled whole pony it will
pop right off.

Now look at the pony setup for some notes on additional items.

First off is you need to look at the ports on your 1st stage
and try to line up the HP port for the button pressure gauge
along with a low pressure port for the 6 inch hose to be
right under it. This is so that on your ascent you can have the
reg in your mouth and still Right eyeball the button pressure
gauge to monitor psi. Remember in a panic attack you are still
freaked out and breathing heavy, seeing the gauge go down will
slow your breathing. And you won't be thinking bolt for the surface.
You'll know just how much PSI you have and at 15 feet you can always
cut short your safety stop and surface on a drained pony.
Remember you want to be able to surface all by yourself from
the deep and not embolize and hopefully avoid getting bent.

Also before putting back on the valve, buy a brass ring and put
it under the valve so you can clip it off with a leash so it
doesn't free fall to the bottom. With this setup I can put the
pony tank under my rightt arm and hold it and still see the gauge,
have the reg in my mouth and have both hands somewhat free
to deal with caught fish, dive flag reel, whatever.

This next shot is the separated reg and pony so you can see it
disassembled. The beauty of the 6 inch hose is that while on
vacation and doing multiple dives, each time you break down your
equipment for the day you are not losing 100psi due to a 30 inch hose
on your pony. It's short and low volume.

And this last shot is the empty pony mount from a top down
view so you can get a different perspective of how it attaches.
Just stretch each band as you slide the bottom of the tank upwards.
To pull the pony is just reach back like you would grab something
out of your back pocket and pull down. Don't forget to pressurize
your pony regulator before each dive to avoid a 1st stage flood
and have it waiting and ready in an emergency.

Email me with questions at Johnoly_at_scubadiving_dot-com.