if we ignore the dynamic effects of yawing and rolling motions, boat physicists will divide the force of the sails into two vectors: the driving force which is aligned with the course made good and the heeling force which is athwartships at 90 degrees to the course made good. The actual amount of heel angle from the heeling force depends on the particulars of the rig and hull, "heeling force" is just a convenient term for the sideways component of the sail forces. Close hauled, almost all of the force from the sails is heeling force with a small driving component. At steady state, the centerboard/keel must adopt enough of a slip angle (leeway angle) to develop lift to balance the heeling force (it also contributes heeling angle of its own due to this lift - one of the downsides of a deep keel). The driving component is balanced by the drag of the hull through the water, and we are at equilibrium. As the boat comes to a close reach and then a reach, the driving component gets larger and the heeling component smaller so the leeway angle is automatically reduced to produce less force. Beam reaching the only heeling force is due to the aerodynamic drag on the rigging. However the drag of the rigging is not zero (on a typical cruiser it might be 20 - 25% of the lift) so the centerboard/keel is still working to that extent. Further off the wind the heeling force continues to reduce and along with it the load on the centerboard/keel. Dead down wind there is no heeling component, only driving component and the centerboard/keel force and leeway angle go to zero.

Yawing causes momentary keel lift until the boat adopts the new course. Rolling causes momentary keel lift since it is below the roll center of the boat: during the roll, the apparent waterflow shifts to the side, producing an angle of attack that resists the roll. This is an aerodynamic effect and can be far more powerful at speed than when the boat is still, which accounts for why a lowered centerboard can reduce rolling downwind.