I've seen the same on my Hobie and Prindle rudder blades ... Remember the Hobie castings w/ that small plastic adjustment screw?

I agree w/ Rolf!!! I would use two layers of cloth tape 2" and 4" to spread the load out.

Little trick: when you know what rudder rack you like ... wrap "plastic wrap" around the blade ... put a glob of silicone inside the casting ... push the blade into place allowing the silicone to ooze out ... it will coat the inside of the casting ....

This makes a "bumper" inside the casting. It can be easily removed and redone.

Sail Safe, Sail Flat, Sail Fast
Harry Murphey
H18mag, #9458/ Fleet54,Div11
P18MX, #86? CRAC