Quite nice, maybe a bit fast, but nice looking. Was first in goal, but I didn't advanced a level. Seems like one have to round the marks really close by for it to count. Varying wind directoins and stealing wind would really add to it I think, if possible to squeeze in. Boat also stops on a dime if there is no wind in sail. would be nice it if would glide a bit forward still.
Great suggestions finally some one who knows how to sail

I have done as much as I could fit in. I have made the rounding of the markers eaiser. You no longer have to be soo close. You still however can not be way away.
I have slowed the game down a bit.
I have added momentum to the boat so turning once moving is a little smoother.
I have add a wind indicator (the red line in the middle of the mini map).
And the wind now slowly changes over time.
I could not get the wind stealing in. It is too much computations to figure out who is bocking who. Too bad I would have liked to get that in.
Here's the new link so you don't have the scroll to the begining of the post.
http://unlimited.woogley.net/games/view.php?id=95Also I had my sails pulled all the way back, then turned and hit forward and my sails completely flipped back around
Yes if the wind is in your back and you change direction you will "Jibe". That is the wind will swing the sails over to the other side of the boat. Many an sailor has gone over board this way. When going into the wind too far the wind will colapse the sail until the "Tack" or turn through the wind is complet. Then the sails will again fill at whatever setting was present before the turn.
Think of the sails being controlled by a length of rope. The up down arrows control the rope length. The wind will simply fill the sail until the rope is taught. But if you turn you can't push a rope so the sail will be blown around until the rope is once again taught. Just like how a real sail boat works.