Look at this video and notice the sail rake on the boats. More like a windsurfer - very much raked back. I know that on a windsurfer when at speed the sail is definiately raked very far back. In fact on a windsurfer we try to touch the clue to the board for speed. It is called closing the gap.

Be patient with the first part of the video and then look at when the race in under way.

http://www.youtube.com/watch?v=B3ldNh38rMM