Eagle Boats
08-31-2006, 10:17 PM
I build a fiberglass sailboat that uses a two part rudder where the lower part can kick up. The lower rudder is made of mahogany. My supplier no longer builds them, thus I need to start doing it myself. I am not sure how to get the airfoil shape on a consistent basis. Any help would be appreciated.
jehardiman
09-01-2006, 10:38 AM
In using a slab rudder you don't need a true airfoil shape, an ellipitical nose and tapered tail is all you need if cord to thickness is greater than 10:1.
Anyway, the way to do it is to make 1/2 molded templates for the shape at several stations along the foil, you will need several is there is any taper. Using your perfered tool, shape the sections at the stations that you have templates for to near net shape. Then remove the material between the shape stations. Finally, get out the long board and finish to the template taking care that the root to tip lines are straight and fair.
Or you could CNC it, then follow up with a long board. Or make a mold and HDF it, if you really want to get slick.
