hans, I don't race but have been in citizen races with "open" categories wherein obviously trained athletes of the kayaking variety competed. Their boats were beyond the nature of fast touring boats and they all had rudders. Not huge gludgy flip up rudders, but small rudders like what one finds on surf skis. So I think a rudder is a great thing if you are busting a gut and paddling like a demon, just make it a little one,3x6 inches should be big enough. I think one can maintain a faster speed over distance if the motor isn't always having to steer. impressive speed in your race