which may or may not be helpful to those teaching the stern rudder to others:
The first two videos emphasize and demonstrate combining stern rudders with boat edging. The last video shows the stern rudder being used without much boat heel and also demonstrates (in a somewhat exaggerated fashion) the "wrist rolling" involved in going from the stern pry to the stern draw.
I don't agree with a statement made in the second video which in effect claims that the stern pry is one of the first turning strokes that beginners learn instinctively but that it is not very efficient. What I have seen beginning boaters (both canoeists and kayakers) use instinctively is a reverse sweep in which the paddle blade starts out too far from the hull (as a result of not enough torso rotation) and sweeps out to 90 degrees from the keel line of the boat.
IMO the stern pry, if done properly, is about the strongest stroke that can be used to yaw the bow to the paddle side for both a canoe or kayak. In a kayak, however, it is often even more efficient to simply switch over to a forward stroke on the opposite side, adding a bit of sweep component if necessary, especially if one wants to maintain forward momentum or move back up onto the trough of a surf wave. The first video sort of demonstrates this.
Gedi Convertible Helmet
Hardshell Kayak Sail Rigs