I have a 2008 Beneteau 40 with the same problem. Again, the dealer has made some repairs, but they and Beneteau say it is normal. Mine existed at time of purchase- boat was two years old and had sat in the yard one year and only lightly sailed as a demo the next year. I have also noted very thin gelcoat in places- almost like it is worn through. My speculation is that this is poor construction by Beneteau. There have been other similiar problems with the boat. Have you figured a way to repair all these cracks?