I found this on Facebook sharing for the kiddies out there who are to cool for social media...
Using 3D software (Blender) this video will explain the physics behind windsurfing. This will cover the following:
1. The force of the wind on the sail
2. Why the board doesn't get blown downwind
3. How you are able to sail faster than the wind
4. Does the shape of the sail provide lift
5. How to steer the board