We’re now four days in to the rudder cassette build – lots of steps and the result looks very strong.
Here’s the beginning of the steering pivot axis (green tube)
That green pipe will be vertical; the increasing angle of the cassette away from the vertical hinge means that the rudder will be tilted forward about five degrees. This is important as the boat rises up on plane and less rudder is in the water, the forward rake helps keep the helm balanced and not get very heavy in the driver’s hands.
There are carbon layers between the tube and cassette, with the rest of the gap filled with foam and putty. (In pink)
Next was wrapping the pivot tube in to the cassette structure with four more layers of thick carbon double bias fabric – look for vertical lines towards the smaller end. And about ten layers of carbon uni-directional in the two areas that match up to the hull’s gudgeons – see the thicker sections along the tube end.
Ok, this thing is ready for cut-ins at the gudgeon points and trial fitting tomorrow. Then the final step is building the steering tiller. The tiller stub is a built-separate piece that will get permanently bonded to the cassette. Here it starts with a foam core, about 26″ long:
This piece was laminated and vacuum bagged with its many carbon layers today and will be fitted to the cassette on the boat tomorrow.
Need to decide whether the 9′ long tiller should be made from wood or foam core and carbon. If carbon, we’ll need to solicit ideas on the fabric layup schedule. Any thoughts?
Greg, foam cored carbon should be your lightest option, as with any load bearing spar the important filaments will be the longitudinal unidirectional. Form up your tapered foam core with maybe 4″ dia transitioning to a rectangular shape at the cassette head and appropriate sweep over the aft deck tapering to1 1/2″ dia. Wrap with bi-axial or better uni at 0 degrees for hoop stiffness then lay up the longitudinal uni and surface finish with a layer of bi-axial which you could join underneath and clear finish for best construction appreciation
Greg, I made mine from carbon http://members.ziggo.nl/arno.molenaar/thrillseeker/helmstok1.html
I use two carbon sleeves and two layers UD, I think it was 300 grams but I am not sure.
I used styrofoam (roofmade) and dissolved it with asseton.
Greg, I did find some more info at Chillax site
Some more info