It veers to both sides of my course and by varying amounts. I've tried adjusting the rudder control but it does not help. It always comes back to course but I'm going in an "S" pattern. In flat water it does just fine. I've not used it much under sail but then you have the variable of sail trim which I know will be a factor anyway. Looking at Cams comment it may be that 30,000 lbs of boat is too much for a linear drive.