Slinging vs.Tank Mounting Pony Bottle

[Aaron528]

I've been using a pony tamer to carry my 13cf pony bottle for local diving. It took a while but I finally got the weight balanced ok by adding a weight pocket that mounts on the opposite side of the tank. Adding extra weight to the opposite non-dump BC pocket wasn't optimal. Now I'm thinking about slinging it, rather than cam band or bag mounting when I take the pony for travel.

There's a lot of divers on here with experience slinging tanks of all sizes. Even with the small bottle, I had trim/balance adjustment issues. Any advice you folks have for weight adjustment with a slung pony, especially if I move to a bigger bottle as previously discussed?

 

[DevonDiver]

I use a BP&W, so I just trap air where needed in the wing to ensure balance. Another option would be to use a cam-band weight on the opposite side... or get an umbilical torch.

If you use an aluminium cylinder, the buoyancy issue shouldn't be that impossible to overcome. An AL-40 is less than 0.7lbs negative, add a lightweight regulator and you're looking at 1.5lbs max. Easy to balance with a trim weight or through wing control.

 

[TSandM]

It is, as Andy says, quite possible to park gas on one side of your BC, to balance an asymmetric load. Technical divers do it with significant loads. I can do it with my wing, and I can't think of anything about the design of other BCs that would make it impossible to do it with them. But the key to doing it is staying horizontal. If you dive significantly head-up, the gas will equalize across the top arc of the air bladder, and you lose the balancing effect.

 

[M_Bipartitus]

I prefer slinging reserve air, if necessary. However, a 13cf may be a little short to fit well the way most stage/deco bottles are slung. Along the lines of Andy's buoyancy comments, most of the small (<50cf) aluminum tanks are in the range of .5 to 2 lbs negative when full. This should be relatively easy to offset by adding some weight on the other side of your body. This could be by adding weight to a weight belt, bc quick release system, or non-release pocket. A trim weight on the other side is not necessary for BPW user as you have some control over which side of the wing the air is in. A few jacket designs allow for this when only slightly inflated, but I wouldn't bet on it.

Since the range of small aluminum bottles only differ by a pound or two in buoyancy, it should not be too hard to move to a larger bottle after getting a smaller bottle working. In fact, as Andy mentioned the full Luxfor Al40 is actually closest to neutral and may require less trim weight than the Al13 you have now.

As you may have likely already read, be careful with proper gas planning and, as with any emergency skill/equipment, practice with and test the pony regularly to be sure it's ready if needed.

P.S. If anyone gives you crap about carrying a pony, just say it's practice for stage bottle / deco bottle management.

 

[Crush]

I sling my 19 cu ft Al pony. I typically drop 3# from my weight when I do so (the pony regs are pretty heavy). Since the D-rings that I clip the pony to are on my chest and waist, the load is off my center line, but not so far off that counter-balancing is required. I suppose that I might benefit a tiny amount from shifting one or two pounds to my right side, but it is not worth the bother.

I found that, with a system when my pony mounts on the main tank (single), my gear was off-balance and prone to tipping over when I was suiting up. This is only a minor inconvenience, but worth noting. I found that, with a tank mount, my surface swims were lopsided - this bothered me, but it was not a serious problem. Slinging the pony eliminated both these issues. I gear up without the pony, then clip on the pony. Also, slinging the tank placed it in front of me where I could see it, look at the pressure gauge attached to the pony, and deploy and stow the hose. My setup involves my primary reg, my secondary reg (octo), and the reg on my pony bottle. To each their own. This setup works for me.

 

[drbill]

I've tried both but settled long ago on tank mounting my pony (with an added two pounds on the weight belt on the opposite side. The reason is that I'm a videographer and slinging a tank often means it gets in the way or my filming, or may hit the bottom and stir up sediment. For non imagers this is probably not a problem (they also don't spend as much time on the bottom as an imager might).

 

[sam1]

I used to dive with a traditional BC and mounted my 19 cf pony on my tank. That worked fine but then I got a BP/W and could not find a satisfactory way to mount it to my tank, so I dived without the pony for a while. I recently went on a dive where I thought the pony would be essential, so I slung it. I should add two things: 1) I expected it to be awkward, but I barely knew it was there. 2) I had planned to offset the negative buoyancy by adding some weight to the other side---but I forgot! And like I said, I barely noticed it was there.