Pony bottles and trim

[Graeme Tolton]

I sling a 30cf pony on any of my deeper dives. I am using a single hp119 tank on my back. I do find that I start to roll a little if i am not offset by a couple of pounds. However, that being said, you are best to try for yourself to see what is most comfortable.

 

[DiverBeth]

On deeper dives I sling a 30cf with my 100 steel. I just started doing it at the beginning of this year. I had the same concerns but found once I was in the water I was fine. Like Leadturn I don't even know it's there but I remember it's there. I practiced in my local quarry a couple of times when I first go it just to work out any problems which I didn't have.

 

[ae3753]

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.

Here's a picture I have from UTD. Per TSandM's comment, it's the wing that's compensating the weight of the tank.

The principle is the same in doubles or singles.

I have a little more detail on yaw control in my Trim 101 article.

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.

+1. In a jacket style BC, you're limited in your ability to trap/manage air.

 

[Gdaaym8z]

Thanks for all of the great information. I am yes going to be diving a single 80 with a Scubapro Nighthawk BCD.....for now. I have decided on a slung 40 with the Dive Rite stage strap. I currently use an MK25/S600 for my primary and will most likely set up the pony with the same reg, I have had zero performance issues and have only heard possitve about this reg. I am looking forward to getting this bottle set up, it will be good practice for stage bottles as those are on the horizon.
I love this board....I haven't been very vocal but have spent many many hours reading posts and have found so much useful info. So once again, thank you all for taking time to answer my questions.

 

[elan]

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.

Well yes. If you dive a single tank and a regular BCD (not a BP/W) you would most likely have to compensate. I did put 3 more pound on my right side when I was slinging my 30cuf pony. Otherwise I was rolling to the left. However once I moved to BP/W with doubles I do not need to shift the weight, even with an AL80 stage + argon bottle on the left. I just adjust the air in the wing accordingly. I put more air in the left side when it's full and less when I breath it out.

 

[Ed Palma]

Hello gdaay,

Here's a photo of my set-up while I was practicing in the pool:

Now, in this instance, this was my first time with a slung 40cf bottle. I didn't shift my weights around, so I did notice a slight tendency to roll to the left. Granted, I'm not adept at shifting the air bubble in my wing yet, as proposed by others on this thread (and by my wreck instructor later), but I was sorta able to control it by small sculling motions with my fins. In salt water, this effect was less noticeable.

My current quandary for trim and ponies is "what regulator to use?" I assume that using a lighter reg would mean less of a swing, thus meaning shifting less air in the wing. Is this correct, or is the weight of the regulator used on a pony not a major factor?

PS: sorry for the picture quality. Its a screen shot from a video I made to evaluate my performance.

 

[LeadTurn_SD]

........My current quandary for trim and ponies is "what regulator to use?" I assume that using a lighter reg would mean less of a swing, thus meaning shifting less air in the wing. Is this correct, or is the weight of the regulator used on a pony not a major factor?....

Hi Doc Ed,

I wouldn't lose much sleep (or spend $$) based on the weight of the pony reg. I tried my Al30 with a couple different regs that were very different in weight (a "heavy" Zeagle Flathead VI vs a "light" Mares Mr-12 Voltrex).... I can't really say I noticed any difference. Breathing the tank down had more effect, and even then was unconsciously compensated for.

Oh, and I only dive singles (Al80).

Best wishes.

 

[BobbyT22]

I spent a good amount of time in a local quarry working on my trim with a slung 19 (left side) and AL80 on my back. I tried all sorts of configurations, and what worked best was two trim pouches on the right side tank cam-bands, a 3 lb weight on the lower one and one pound on the upper one.

 

[Gdaaym8z]

It's been awhile since I looked at this thread....I have changed a few things since the original post. I am now diving dry and have a BP/W (single) set up. I did go with an aluminum 40 slung and thanks to all of the great input from everyone here on Scubaboard, I couldn't be happier. Just wanted to say Thank you again!

 

[Crush]

Dredge. Sorry.