I have a 1986 Catalina 36 and the last time I was out we had a great sail day . Every time the boat got to 7.5 knots it took a hard turn to the starboard. If we were at 7.3 or 7.4 we were fine. It is a 3000 plus unit, I installed a new circit board this past winter after water damage. The auto pilot would always bring the boat back on course afterward. I also have a problem with the wheel drive handle popping up all the time.