Lattely i've been playing with my 3D printer.
To me it seems that creating small and precise profiles for our boats is difficult, unless one has a mould.
So this si a sample rudder for our national class boats:
It was printed in two hlafs like this:
from pla plastic, glued together with super glue:
the shaft is 3mm brass tube, otherwise i use aluminum with a 2mm carbon rod in the middle.
Poliester putty, sticks well to the plastic
and finally spray paint
5 layers of it to smooth out the layers completely.
I was in a hurry with this one, so pre season testing can begin, for future rudders car paint will be used.
In my case build time was reduced greatly. No waiting for epoxy to cure, no sanding the wood core..and the shape is surely as defined by the airfoil chosen. It took the printer 7 hours to print it. 2 hours of work were needed to glue it and finish the surface.
The stiffness is alright, it is not as strong as glasfibre rudders, but at the speeds our boats create it won't bend or twist.
Weight is 35g, not light, but when building three different boats a year and testing many different foils it certanly saves a lot of time.