I can only think of a couple of things it could be...
1) the hulls aren't symetrical. This is a pretty low likelyhood but could be
2) the hulls aren't attached the same way to the cross beams. Again this would be very very strange but could happen
3) there is some weight you aren't accounting for. Holding tanks
tanks, and anchor
chain are the first things that come to mind... House batteries, galley
, hidden drugs... Something has to be throwing the weight off to one side.
My first thought assuming the tanks are full is if the anchor
chain is stored in one hull? If so the far aft corner from the chain would lift
to compensate. But I wouldn't have thought that much, and I would have expected the hulls to be different as well.