Not quite finished entry for http://midwestgamejam.org
left/right to steer, 'z' to draw in the sail, 'x' to let it out. Finish all the waypoints without running aground!
General Sailing tips:
Sailing with the wind is easy enough, just let the sail out all the way. You can get the most power this way, but you can't sail faster than the wind.
To sail perpendicular to the wind pull the sail in to about a 45 degree angle. This will give you a lot of power for acceleration. Then you can pull the sail in even more to trade power for speed. It's sort of like gears on a car, and you can sail much faster than the speed of the wind this way.
Lastly, you can't sail directly against the wind, but you can still sail well up to 45 degrees of the wind if you pull the sail in close. Then just zigzag back and forth across the wind. This is called tacking.
1.1 - Made tacking more forgiving and added red limit lines to make the sail mechanic more intuitive.