Originally posted by Ollie
Rounded trailing edges produce vortex sheading that can power flutter.
I feel the opposite. In my opinion, the bulky trailing edges may inhibit flutter at high speeds. My reason for this assumption is my knowledge of r/c boats. My unlce has a racing hydro that is capable of 70+ mph. This boats rudder is knife edged at the leading edge but 1/4" thick at the rear. As asked some guys about this, since it seems like it would produce more drag, but they said it keeps the rudder from fluttering since it creates an air pocket behind the rudder. It seems like a sound enough reason.