Custom Rudder
Buidling a new rudder from scratch
Instead of repairing the existing rudder which was poorly shaped and built of inferior materials, I decided to build a new one from scratch. Given the available tools, timber and my inclination towards working with wood, I chose to build the rudder using strip planked construction. The first step in the process was to mill rough sawn mahogany into 100 strips with dimensions of 1500x25x25 (mm). Each half of the new rudder blank consisted of 50 strips that were edge glued with epoxy. Care was taken to reverse the grain direction of every other strip in the glue layup for maximum stability in the final product. Once releasing the two rudder blanks from the clamps, I marked out and cut coves for the internal framework with a large cove bit on a router. To accurately cut the cove for the large 2” diameter rudder stock, I used a series of cuts with a circular saw and finished by hand carving with a straight gouge. I then re-drilled and tapped the rudder stock to accommodate 5 larger ¾” silicon bronze rods that would provide stronger internal reinforcement.
To laminate the two halves together, I first laid thoroughly wetted out, heavy fibreglass cloth over each half before positioning the internal framework in place. I then applied thickened epoxy to ensure there were no voids around the stock or framework. It was important to take extra care to orientate the shaft accurately before finally applying sufficient clamping pressure.
With the rudder now in one piece I could begin the process of cutting the foil shape. To ensure the most efficient rudder It was imperative that the shaping be done accurately. Using NACA 0014 foil specifications, I printed 1:1 paper templates of the desired foil shape before transcribing to plywood to make a router jig that I used to cut a symmetrical foil shape from the blank. I formed the last 50mm of the trailing edge from solid fibreglass sheet for strength and ideal shape.
The final step of the build process was to sheathe the whole rudder in several layers of 10oz cloth + epoxy to provide abrasion resistance and prevent water intrusion.
