How would they keep the bow pointed into the turn?
My understanding is they were doing a “swing check”, a counter steer to stop the swing of the ship’s bow.
My interpretation of the article is that they crank the rudder to the stop in one direction, and observe that nothing unanticipated happens, then crank the rudder to the stop in the other direction, and observe that nothing unanticipated happens.
While this is happening, the rudder causes a sideways force on the stern, and only the stern, so the ship turns.
Take a toy boat, put it in a filled bathtub, and push sideways on the stern; it will turn.