First of all I must apologize for not actually being a Tiki builder; I'm currently building a wooden 18ft mini ocean cruiser loosely based on a double ended, long keeled George Buehler design.
A friend of mine who owned a Tiki 21 many years ago suggested I use the same rudder lashing system as his Tiki instead of traditional metal gudgeons and pintles. I've researched on the web and have found several Tiki photos clearly showing the layout of rudder/sternpost lashing holes and the general rudder arrangement but I'm in need of help on how I should shape the short portions of the rudder leading edge and sternpost trailing edge where the lashings actually form the hinge. Some seem to show a fairly flat surface with radiused edges. Is this OK or should I make the bearing surfaces of the rudder and sternpost truly semi-circular?
My friend cannot remember the exact construction details as he purchased his boat second hand rather than having built it, so I thought I should seek advice from those who have direct experience.
Any hints would be much appreciated.