We did something similar on our PMD, though I can't remember whether that was our own idea or something suggested in the build manual.  "It seemed like a good idea at the time."  Still seems like a good idea.

If you are really going to be dragging the boat over some rough stuff, I wonder if bronze half-oval strip would be appropriate?  It'd have to be screwed onto the edge of the plywood, maybe a problematic thing, so you'd probably want to drill/fill/drill for the screws and make sure everything was thoroughly bedded down with sealing compound so water wouldn't get down into the plywood skeg.

Maybe somebody smarter than me will weigh in here on that idea.

.....Michael

+1 on everything Gramps said. I've been using a half oval brass strip on the skeg on my Brand X dinghy for over 10 years now. I attached it exactly the way he says, with the added feature that I countersunk the screws flush with the strip. It's still the original brass.

Laszlo

   I would. I fillet at the attach point to the hull and tape reinforce with glass on the blade. 

I think the brass strip is a good idea with counter sunk screw heads. Typical wood boat thing for that part of the boat.