Like most first time tries at a mod...my original design was fraught with issues. The Wal-Mart cutting board rudder wasn't long enough. Setting the rudder shaft BELOW the stern allowed it to grab, catch and finally break..when I dragged the yak to the shoreline. I learned a lot....for very little money.
The new design, shown below, also uses a Wal-Mart cutting board for a rudder, but it is shaped like other yak rudders always have been shaped. The kick up section is now mounted on Mike's aluminum and is far stronger. The entire unit rides ABOVE the stern, so nothing extends down to catch and break. The former broom stick shaft has been replaced with electrical PVC which is far stronger, yet flexible to give a bit if I hit anything.
p.s. please disregard the erroneous date on the photos. It is from a new camera that has a screwy date setting system. But it was cheap and waterproof.