I have not experienced cracks in my rudder. However, the previous owner was pretty careless with my rudder. Therefore, I had to repair some large chips etc with fiberglass and Epoxy. Sanded it down and then painted it with AwlGrip. The AwlGrip is a pain to work with, but the results were beautiful. It has a tough finish that sparkles like mad since the AwlGrip has so much clear coat in it. Rubbed a few times when I ran aground, but didnt scratch up too badly. Did the same finish on the carbon spinnaker pole since the clear coat was peeling of the pole. Looks beautiful now, if not more tasteful than the black. Although not as high tech.