Steering problem

[wjmarch]

Looking at a Cal 33 - under power wants to steer left and will go hard left and stay there (circling) if I let go of the wheel. Current owner repowered two years ago. Other boats of this model don't do this. Steering under sail is neutral. Was this a repowering setup error or ?

[Faster]

This is not an unusual characteristic of a boat with a balanced spade rudder. While the balancing area lightens up the helm under sail, the propwash can impact that same area with some force and tend to push the rudder in one direction or the other, depending on prop rotation.
Perhaps when repowered, the prop was changed also, or the shaft moved a bit and put the prop closer to the rudder and that's why it's worse on this boat than others.
Boats with unbalanced skeg rudders, or with the balancing tab out of the prop wash will have a less pronounced tendency to turn in this way. It's just something you have to live with.