Modified rudder construction
This is a description of how to build a rudder. It describes the way I built mine. If you do not have a table saw you can probably get a carpenter to help with the shaping.
1. Make a blank by epoxying two boards together to form a 1 5/8 by 60 by 11 1/4 inch plank. Do not use a soft wood such as pine or fir. Use a hard wood such as mahogany, oak, maple,or ash. Even poplar which is not so tough seems to be adaquate.
2. Make a pattern of the shape you want out of 3/4 pine board. Attach the pattern to a snother board. It is important that the width of the board must match the pattern width exactly.
3. Set up a table saw with a dado blade that is 3/4 inch wide. Set the fence up so that it is 1/2 inch from the blade.
4. Place the pattern on the saw and tilt the blade so that it will cut at an angle to match the rudder shape. Slowly raise the blade and cut the board which you fastened to the pattern. You want the saw to come close to the pattern but not cut it. This is the setting for the first cut on each side of the rudder. Pass the rudder through the saw and turn it over to do the other side.
5. Lower the blade and move the fence 3/4 inch to the right. Raise the blade as you did for the first cut. get close to the pattern but not touching it. Again pass the rudder through the saw and turning it over for the other side.
6. Repeat this again.
7. On the nex several passes the rudder must not go all the way through the saw. The top of the rudder where it fits into the aluminum channel must be full thickness so you must calculate where to stop. On one side of the rudder you must stop before the end and on the other you must start with the rudder part wag through. Mark the rudder and the fence with tape or pencil lines because you can not see where the blade is cutting.
8. When you get near the thick part of the rudder you will not be taking off much wood so jump to the front edge and make a few passes there. The idea is not to shape it perfectly on the saw but to do the heavy removal work and make the finishing easier.
9. Now is the time for changing to a belt sander and making it smooth. If the work on the table saw was done carefully there is not much heavy sanding and the shape should come easily. The aft end of the rudder where you left the 1/2 inch of wood will now be sanded off.
10. It is now time to shape the head so that it will fit the aluminum channel and be able to swing up. Since the front of the rudder is 3 inches further forward than the original, the rudder has to be notched so it doesn't hit the stern of the boat.
11. After the head is shaped cut the rudder to the length you want. I found that 43 inches down from the channel was the best length.
12. When the shaping is done place the rudder in the channel and see that it is a good fit. Then holding it firmly forwad in the channel drill the pivot hole;. Make sure the rudder will swing up when you are finished.