Doubles Wing - stability?

[vicp]

Not meaning to start a donut (torus) versus horseshoe debate, but:

Using a 65 lb horseshoe wing (Hollis BAC65 - large wing) with doubled Faber LP85s (smaller tanks), I found the the rig to be highly unstable. If in a horizontal (cave) position, it seemed OK, but once you went head-down or on one side, you tended to keep going that way (hard to return to horizontal). Using a smaller 45 lb donut wing (Hollis C45) with the doubled LP85s, it was much more stable. I have run across a good deal on a smaller horseshoe doubles wing (Hollis X37, "Cave-Cut" 37lb) and was wondering if I should pick it up as a spare but may not be able to try it first.

Question is:

Was the original instability due to the size of the big wing (65 lbs) or the horseshoe shape, or both. The smaller donut works much better with the double LP85s.

How will the small (37 lbs) horseshoe compare? Anyone diving double LP85s with a small hoseshoe wing (Hollis X37, HOG 38, or comparable) please chime in.

Thanks

 

[TSandM]

I don't know -- it's been my experience (using a 40 lb horseshoe wing with 85s) that my gear is carefully balanced for the horizontal trim position, and once I leave that position, I am no longer stable. This makes a lot of sense, given that the center of mass of the tanks (which are very negative) is not aligned with my center of mass.

One of the magnificent surprises of my excursion into sidemount in Florida in December was discovering that, with the tanks aligned with the center of mass of the diver/tank system, I was suddenly stable in ANY orientation.