Any of you out there ever hear that humming sound when you really get the boat really cooking along? I have a H16 and I think its rudder cavitation. I have EPO rudders, and the trailing edges of them seem a bit thick, and I was considering thinning them down a bit. I was thinking the thick trailing edge would create more drag and turbulent water at trailing edge, and this is whats causing the humming and drag. I'm gonna slap on a fresh coat of epoxy with graphite mixed in...glass fiber was starting to show through, so I sanded them smooth. Thanks in advance for any advice on this!