I bet he could have gone a lot faster, too!
Sailing a cat on a run like that (directly with the wind--note the sails are "wing-on-wing") is like driving a car in first gear. The wind is only pushing the sails, whereas when it is closer to a 90-degree angle, the sails act like wings and can push to boat to over twice the speed of the wind. It's a crazy experience.
http://www.youtube.com/watch?v=WuRvujRFsjY