Rudder Woes

<< First  < Prev   1   2   Next >  Last >> 
  • 02 Jun 2020 15:31
    Message # 9009568

    I recently noticed a few drops of water appearing on the underwater part of Hobbit's rudder. An investigation uncovered a massive amount of rot. About 20% of the rudder, I guess.

    It was built from four layers of 1/2" plywood species not determined. I determined the core two layers are sound but much of the "cheeks" I have removed.

    The repair will be more or less straight forward. First, I will dry out the rudder as best I can and replace the ply with more ply and reglass the whole thing. Wish I had discovered this long ago.

    The basic problem was building the rudder in plywood in the first place. One small entry point can allow water to enter at the edge of the ply and progress unhindered through the whole thing. Not across the grain but with the grain. This not to say that plywood should never be used in rudders. But one needs to be aware and check them out from time to time.

    I once worked for an aluminum boat building company which was building Canada's entry into the America's Cup race in Australia.The shop foreman was a Brit who started work with boats at the age of 14. I asked him what kind of rudder construction had the fewest problems. He described what is a bread-and-butter rudder built from solid wood, with reinforcing rods extending from the rudder post to just before the trailing edge. The rudder was then heavily glassed over with epoxy resin.

    Teleport's rudder was made this way with SS threaded rods perpendicular to the rudder post spaced about 6" apart.  It was built with the leading edge face down on a table with SS rods fitted to the leading edge piece standing perpendicular and 1", predrilled Douglas Fir pieces lowered down the rods and glued to the next layer. I made the mistake of fairing the final shape with a layer 1/8" birch plywood. BAD idea. It rotted and was replaced with fiberglass and epoxy. As far as I know, the rudder had no more problems.

    I would build Hobbit such a rudder but I'm confident we will get along with the old one for now.  Gougeon show a method laying the rudder on it's side, all pieces being the same thickness. The shape is formed later.




<< First  < Prev   1   2   Next >  Last >> 
       " ...there is nothing - absolutely nothing - half so much worth doing as simply messing about in junk-rigged boats" 
                                                               - the Chinese Water Rat

                                                              Site contents © the Junk Rig Association and/or individual authors

Powered by Wild Apricot Membership Software