....The dealer seems to be at a loss and they've contacted Beneteau and Neil Pryde looking for solutions.
I have ironically just gone through some issues my self in the third season with our 331. I just posted some thoughts and I hope these observations will help. After "discovering" the cure and spending the week sailing here in Chicago I feel much more comfortable with how the main furls and I als have the US Spars.
Yes proper halyard tension is important but only to the point of normal luff tension in the sail. Which would be where you would be when your sailing.
I much bigger effect is the positon and freedom of the "clew" (aft corner) of the sail. The main is cut at an angle and the foot (bottom edge of the sail) tilts up about 7-10 degrees.
It is hard to describe but I will try, it is critical that both the bottom foot as well as the leech (aft edge) of the main maintain the same approximate tension. If the boom is too far down the sail will not be free to roll up and the leech will be in too much tension and start to bind up.
Here is my method (that at least works really well for me) now after my third season:
* Head up into the wind to let the main luff free
* Loosen the mainsheet a few feet
* Critical part: Loosen the boom vang, my is lead aft so it's easy
* Critical part: Tighten up the topping lift and raise the boom maybe 6-12"
* Start to winch in the inhaul
* Ease off on the outhaul at the same time and let it go free if there is any breeze. I used to keep some tension on the outhaul but now all week I just let her go and luff about. Rolled in much easier and rolled in nice and flat and even. I suppose if it's dead calm or blowing like stink I would keep very light tension but so far this has worked great
Anyway this is what works well for me and I wish you luck. I can assure you everyone on the this board has a method they use and if it works great. This is our third season on a 2004 model 331. I did add a brand new main this year which maybe a crisp new main is less forgiving which is why this year I had more issues then in the past.
Regards,
Craig