Pony bottles and trim

[Gdaaym8z]

Hello, I am considering getting a pony bottle (30 cf) and will be setting it up to sling, I have a buddy that dives a 13cf that he has mounted to his primary tank and he has to add weight to one side or the other of his BC to keep his trim balanced out. I am wondering if anyone has this same issue when slinging? Also does anyone have any photos of their set-ups?
Thanks.

 

[wxboy911]

I dive a 30cf slung on my left shoulder and the only change I made to my weights was moving 1 lbs from the left front to the right front pouch. If I don't I notice my balance is a bit off.

 

[LeadTurn_SD]

Hi Gdaaym8z,

I dive a BP/W and I sometimes sling an Al30.

What I've found was that if you sling the tank properly, it pretty much "vanishes" underwater. I don't notice it. I did not need to shift any weight.

What I think happens (at least with me) was that you automatically adapt for the very slight difference in trim (a very slight tendancy to roll to the left with tank slung off left shoulder and left waist belt D-rings). What I also think happens is if you sling the pony too loose (i.e., to far from your body) you'll feel more of a tendancy to "roll".

In the end it is whatever works best for you, but I'd suggest trying it first without shifting weight.

Best wishes.

Edit: I forgot to include a link on how to do the rigging. Here it is:

http://www.dir-diver.com/en/equipment/stagebottle_rigging.html

This rigging is easy, cheap, and works well.

 

[spectrum]

I do offset my weight to counteract a slung 19.

I do know that the one time offset to the wrong side I dive like a turd.

Pete

 

[TonyW388]

Hello Gdaaym8z,

I currently have a AL40 sometimes slung on my left side. It is attached to my chest ring and hip ring on my scubapro knighthawk bcd.

I've had several dives with it and some pool practice(limited experience) with my pony, but I have not shifted any weight as of yet. In fact, I usually forget I have it on in the water. I don't seem to notice it is actually there until I practice deploying and using it, or when I am getting out of the water.

My set up is similar to the third tank(far right) in the link below, except I use surgical tubing for my hose retainer.
OMS SCUBA Stage Bottles & Cylinder Bands http://www.OMSdive.com

 

[TSandM]

I've dived with an 80 full of 32% and a 40 full of O2, and I didn't move any weight, and I didn't notice any tendency to roll to the left. You just move a little gas into that side of your wing (or BC) and it evens things out. You do need to be pretty horizontal to make that work, though; otherwise, the gas just goes to the top of the BC and won't balance you.

 

[DA Aquamaster]

I'm with Lynn on this. Technical divers routinely sling stages and deco bottles. An AL 80 and an LP 45 are probably 6-7 pounds negative when full but I can carry both of them on the left and have no issues with rolling.

A minor difference of opinion or pont of clarification but most technical divers also are not perfectly horizontal but are instead about 5 to 10 degrees head up, at least in terms of the angle of their tanks, and wing, since they still have to see forward from a comfortable neck position. But it still works as the air cell bends up slightly so that you can still trap a differential amount of gas in the left and right sides of the wing without it equalizing across the top of the wing.

The bad news is that with a poodle jacket, you may not have the same capability as the high point of the jacket is also where the cross flow from side to side occurs.

 

[Doc Harry]

What I've found was that if you sling the tank properly, it pretty much "vanishes" underwater. I don't notice it. I did not need to shift any weight.

1+

I sling multiple stages (most typically an AL40 and and AL80) on my left and have a 13 cubic-foot dry suit bottle on my left, and I've never noticed any trim problems. Like LeadTurn says, they sort of "disappear" once you're underwater.

 

[paddler3d]

I assume you'll be diving a single tank config. Some of the previous posters that mentioned have no problems, may be diving doubles.

I just recently went to doubles from a single with a slung pony.

I did find that I had a slight roll to the side with the pony when I was hovering. I corrected it with a sculling motion with my foot on the side of the pony. I wanted to stop this foot motion and become motionless like my dive buddy. I ended up getting an XS weight pocket that I could put onto my harness. I put a pound or two in it and it made a big difference.

Frankly, after diving doubles, I don't know if I'm going to go back to a single with pony. With doubles you are stable. It was pretty amazing.

 

[redacted]

When I first started carrying a pony, it was a hard mounted 13 and I did find I needed to add a 2 lb weight to the opposite side of the tank to keep it from twisting me. When I reconfigured to a slung rig, I did not notice as much of a twisting force. And the little that remained I managed by shifting my weight belt a few inches to move more weight to the opposite side. I have also slung an AL63 and it was no more difficult than the 13 (once in the water).