A real puzzler. I've sailed the 39 and 46, but never heard of this before. What could be causing your main to overpower that big genoa
? Does this happen on all points of sail? I would check the tensions on the standing rigging
, and especially the forestay. If slack, might it be allowing the mast
(and both sails) to rake aft, say on close reaches or beats? Perhaps a consultion with a rigger might help. You have a great boat
. Good luck.