Rudder Construction

[Ed Neal]

I'm about to start the rudder construction for my 12ft. Ellen sailing dinghy. The rudder is approx. 3/4" X 34" X 12" at it's widest. What's the best construction technique for building up the blank? I'm using black walnut and epoxy. 2 boards or 3 to prevent warping? Possibly more? Should I use spline joints or edge glue with brass / bronze rod inserts? What about edge scarf joints? Rabbet joints? Tongue and groove? Too many choices, not enough experience.

[Will]

Ed check out the WB article by the designer/builder of the boat .

[John of Phoenix]

This should be WAY more info than you need on rudder & centerboard construction.

http://www.okdia.org/tm/tm5_foil.html

Look at figure 1 (a link at the bottom of the page) for ways to avoid warp.

FWIW here's mine. The curved piece is the thwart and the center board is barely visible in the back, but the rudder shows up ok.

http://bluemax44.home.pipeline.com/bailer2.jpg

I just edge glued all my foil blanks with epoxy then took them to the lumber yard and had them plane the blanks down to an even thickness. One could grow old doing that with a sander. Then I cut the blanks to shape and cut a curf into the front and trailing edges and filled it with epoxy thickened with microbeads and silica (sanding dust would work just as well) to add strength to the edges. There are a number of methods to shape the foils, some more labor intensive than others, and a couple that are real two six pack jobs. I came up with a table saw method that worked very well. It's a bit complicated, but it produces a very accurated foil and, in the long run, is probably faster than most of the others and it's certainly easier. E-mail me if you'd like the details. Finish up with a layer of 6 oz glass, a couple fill coats of epoxy, three or four or six coats of varnish and your almost in the water!!

[Hugh Paterson]

Hi John, is the construction of the thwart the same as in the rudder, only edge glued, just curious never seen a thwart detail like that (only rudders), It looks cool though.

Shug.

[John of Phoenix]

Hi Shug. Thanks for the compliment. Yes, pretty much the same construction for the thwart. Just edge glued, while being bent onto a form to get the curve and heavily clamped to keep all from flying into space in case anything slips. I used a 3/8" roundover bit on the top edge and 1/8" on the bottom to dress the edges. No glass needed, but six coats of varnish help protect the mahogany and poplar strips from dings and scrapes.