by peter ross » Tue Dec 30, 2008 1:42 am
Keels, well if I haven't had my fill of them lately..........they should remain in the boat at all times.......................
Cost is the ultimate issue.
I'm in the early stages of a new build project and time is hard to find for that poor <25. I have a 100lb roll of prepreg carbon to build the rudder and keel posts from. Even though this particular lucky find has an extremely long "out life" it should be used up soon. I usually build several posts and use them as demand calls. They are baked at 275 degrees and at or greater to autoclave pressure, using mechanical clamps, aluminum molds and mandrals.
Again, I can not design and support these rudders with real data. They really are seat of the pants use of materials and shapes that "look right." I do use real NACA sections and other stuff, except use of disclosure protected shapes. Kevin Farrar designed Gnat's rudder, using an 11% section we liked in the keel. I can consult a friend who will charge more for the design than I will the build. There is no way I am going to under build them, I don't like to build parts that break. I will also only build a rudder using my method, I will not build a carved foam rudder.
Back to square one, it's alot to ask someone to trust a shape developed by someone with limited education, and too much chemical exposure. But a carbon rudder at the cost of a low tech rudder. For the 25's, Gnat's rudder on a stainless sleaved post. Sleaving the carbon post allows the use of the existing tube. Keeping your hands off the boat is the key.
Modifying/scaling, Gnat's rudder for the 32 on a sleaved post would be my suggestion. Go deep, take the hit.
My shop is at my house in Jamestown, if anyone is in the area, please feel free to visit the new shop. Gnat is here now, the new rudder with it's boulder damage, a must see if interested in one of these (buzz time) unmatched blades.
Peter
401-207-9326