Ok, does anyone know why my foils hum? One rudder and one d/board get a real sing song going as soon as the boat reaches a certain speed. It can't be fast and I'd like to eliminate it but I'm at loose end having checked the alignment and I've also tried fairing but no result. I have a suspicion it might be that the gelcoat isn't bonded to the glass laminate in some places. That's about all I can think of as being the culprit.
Any other ideas?
Bern