Catalina 350 International Association

Finally got out sailing, no wind. Well we motored some. Go forward and within half a minute doing circles counter clock wise. Starts with a little creep of the helm and propagated quickly to hard to port. Hasn't happens before. Engine at a bit above idle, 1000 rpm. No swell to kick it over. Any ideas? Hand on the wheel doesn't detect any pull. Seems to handle normally otherwise.

Four years ago our boat would arbitrarily do hard turns counter clockwise when auto pilot was engaged. Never knew when it would happen. When it did happen the wheel seemed to lock and we had to take off the auto. Raymarine told us to send in the course computer. They found a connection issue, fixed it and returned it. No problem since. But I notice you said nothing about the auto so this may be not help you.

Not while on auto pilot. Have wheel balanced going straight, hands off wheel. Calm seas no wind.

I have hull #35 and it has done this since new. I think the prop wash past the rudder starts the process and the more the boat start to turn, the faster it turns to full rudder stop. I learned not to take my hands off the wheel when motoring. It does not do it with autopilot for obvious reasons.
Barry Dupuy
s/v Morning Star
Kemah, TX