Hakan,

Maybe you need to buy a Nacra product. I have sailed a I20 in 2 Worrell 1000's ( that is 2.000 miles) and a lot of other races and only broke a rudder from backing up in the surf and a spin pole from shrimping the kite. We had winds up to 45mph and days with 8 foot waves and the boat did just fine. All manufactures can have a bad batch of rudders or boards.