Bubbers, read the post above.
yaw damper authority is a fraction of the full rudder travel
Meaning the yaw dampers maximum input can only mover the rudders a fraction so can't have caused violent yawing.
For example the 747 rudder can move +/-32 degrees however the yaw damper can only move the rudder +/-4 degrees.
You need a power control unit (PCU) failure like the 737 to command full and violent yaw.