Question Choptima Rebreather Users and Trimming

[addohm]

Okay so I just got my Choptima back from annual service and I need to really nail down my trim. I'm 5'10" 180 lbs. I'm typically leg heavy. My OC sidemount wing (xdeep) is set up such that the being is as low on my bag as possible while still accomodating a butt plate, and 4# on the second from the top spine pocket, and my trim is perfect from full to empty cylinders. With the chop though, even moving the weight to the top most spine pocket, and raising the chop as high as possible (almost to the point where I can't unclip the top clips), the tendancy is still leg heavy. So much so that if I don't move I end up vertical. This makes stopping, especially shallow water deco stops, extremely annoying and unnecessarily tiring.

Am I wrong moving it up? I realize that the counter lungs being higher make my upper torso more buoyant but the thought process was getting the weight of the tank, 1st stage, and scrubber as far away from my legs as possible.

If at all possible, I'd like to keep from adding more weight as well.

Thanks for your advice in advance!

 

[Capt Jim Wyatt]

What fins?

 

[addohm]

I used to use JetFins (Negative), I now use EddyFins (neutral).

 

[Capt Jim Wyatt]

I used to use JetFins (Negative), I now use EddyFins (neutral).

Did that help?

 

[addohm]

No not really. The leg heaviness is pretty bad. It's one of the reasons I'm here asking "up or down" because the top of the rebreather is very buoyant relative to the bottom, even when maintaining MLV.

 

[lostsheep]

What cylinder are you using for O2?

 

[addohm]

AL13

 

[JackZwykle]

For different reasons we have the same problem with our Se7ens. In configuration we have them they're insanely "ass heavy" and even with floaty fins turn us upright in seconds.

The only solution we came up with that works - lead on shoulders on the harness. Perfect trim, no more problems.
Lead is where lift from lungs / counterlungs is, can be adjusted well.
Working on printable releasable attachment.

 

[jmark18]

My buddy and I now have our O2 bottle mounted on our backmounted doubles with cam straps( the ones from the Choptima) . It makes trim easier and makes climbing the boat ladder MUCH easier. Connection is a QC6 from the bottle to the O2 input .

 

[Dsix36]

I noticed a tendency to become foot heavy during a dive with my Choptima. I was weighted and trimmed perfectly in my sidemount setup and it remained that way when I clipped on the Choptima. During the dive it would almost always end up changing. After many dives and trying to tweek things, I found the Choptima was not held securely and would shift an inch or so lower during the dive. Shortening the top straps to the point that it was a real pita to clip on solved the problem.