Hi Tony, of course not a dumb question. The stocks ones work fine for me, so

- I'm not want to replace my rudders --> but a friend.
- He think about it because the stock ones he got are really noisy over 8-10kts
- I recommended he to sand the trailing edge of the foils, a bit asymmetrical, he tried, but it became even noisy. Today he will try it reshape again, like THIS.
- He think a stiffer rudder will not resonate, so it is also an option.
- Otherwise I had no information about the stock ones are reinforced.

regards
Sanyi