[BigCat69]

"I would think the goose-neck would be the weak link since having the sail off-center creates a lever arm for the forces on the mast down low. Also, if your sail is far off center doesn't that put your forward thrust further off-center and add to the turning force of the boat, making it more out of balance?"

I didn't quite follow this. Which rig / boat is it directed to? If you are talking about BigCat 65, it doesn't have any goosenecks. If you are speaking of biplane (aka tandem) rigs, there have been many which have reported no difficulties with off center masts and sails-Cool Change, Pho, Cat2fold, Dragon Wings, and Magic Carpet are a few that come to mind. In general, catamarans aren't very sensitive to balance issues-you will find their daggerboards and keels vary widely in their locations relative to their CEs. Monohulls pick up much of their weather helm by heeling - the CE moves outboard, creating a lever off the boat's center to leeward. Cruising cats, of course, don't do that, as they don't heel more than 5% or so.