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Homemade rudder for Surfski

The stock rudder for my Epic V10 surfski catches kelp and weeds so I decided to build my own "weedless" rudder as a replacement. Here's how I went about it. . .
 
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Step 1: Materials

This is the second time I've made a surfski rudder. The first time I used marine plywood but this time I decided to use balsa since I thought it would be easier to shape and I would be glassing the outside for strength anyway.

The stock rudder is about 5/8 inch thick with a 3/8 inch diameter shaft. I bought a piece of 3/8 inch stainless steel rod from a metal supply store and balsa from a hobby shop. Two part epoxy resin and 4 oz. fiberglass cloth were left over from another boat building project so I used that.

Step 2: Rudder shaft and rough shaping

I measured the overall dimensions of the stock rudder and carefully measured the shaft length, diameter, set back from the leading edge, hole diameter, etc. Obviously the new rudder has to fit the boat in the same was as the original so whatever measurements it takes to get that right. I decided on a rudder rake angle of 38 degrees from vertical based on measuring some other weedless rudders from other boats. The width and depth I kept the same, just had it swept back more.

These measurements were traced onto a piece of 3/8 inch thick balsa. The stainless steel shaft was bent and drilled then placed over the balsa and the outline of the shaft traced onto the wood. Balsa is soft enough that cutting out a channel for the shaft to fit into wasn't hard. I used my table saw to cut out the rough shape and a utility knife and Dremel tool to cut out the slot for the rudder shaft to fit into.

After the shaft was fitted into the balsa, I taped it off, mixed up some epoxy and poured it all around the shaft to lock it into the balsa. Let it cure.
MerleCorey7 years ago
i have done this intrestingly enough for a waveski needed five skegs, i built three large with a leading and tail end and used two smaller ones from a fish. the shape i used was closer to the shape of the original fins though... we dont have many problems with kelp in so-tex.
For the second rudder you might look at the many "weed fins" made for windsurfers. At swap meets, you can pick them up really cheap. Then, instead of fabricating/faring a fin from scratch, maybe you could just trim the existing windsurfer fin, rout a channel in it for the rudder shaft, and then bond/laminate the shaft in place.
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