Sounds like it's undersized for your boat. I only had that problem once many years back - upgraded to the proper sized unit and that went away.I know they are not cheap. I got a price for a Hydrovane and that was £5600. I have the bolt on wheel pilot but they aren’t much good. The tiny drive motor isn’t man enough to hold the boat especially if it starts to blow a bit It seems to take to long to react so by the time it has the boat is heading off in another direction. It’s only good enough if the sea is flat and you need to put the sails up or grab something from below
dj
p. s. - I like the hydro vane. It's what I'll put on mine.