Carbonfibre keel/rudder?

[Robin Larsson]

Rob,

Thanks! That sounds good, I'll have to think abit more about it. The keel will most likely be Weldox, slimmer fin, much cheaper and easier for me to make.
The rudder on the other hand, carbon would be very nice indeed, but that depends on if I can manage to dimension it right by myself. Not that I dont wanna spend the money to have one of you real pros to design it, not just that atleast(after all, I´m on a budget) But I really want to do it myself, for the training and satisfaction it would give.
But the rudder will probably be next, first the keel.

Rob, I´ll remember your offer

But now, the design of the keel. Foilshape and planform and so on. I read both Eric's and Vacantis articles in Proboat. I feel that the NACA 63010 foil feels like a good choice for the fin. I was thinking about a tapering fin, maybe 900mm topchord and 600mm bottomchord. But that will make the skins in Weldox much harder to get into the right shape, atleast I think so, will have to make some test in the bending machine.
But it would surely be easier to get a good foilshape if I make say 800mm chord all the way. Straight leading and traling edge, no sweepback.

Would that be very much worse then a tapering keel?
There will afterall be a rather big bulb in the end.
And making it lifting feels more and more attractive, 2.8meters draught when sailing would be nice.

Also, I made a 3D drawing with a bulb, a revolved 63-010 foil, it gets a bit long to get the right volume(about 150liters) 3.3meters long is a to extreme i think. Does anyone have a good suggestion on a different, low drag foil? Just a thicker 63 series? The bulb will not create lift anyway? Is there some foilshape that would have lower drag?

I included the first draft of the keel, in .dxf if anyone wants to see.

Would a trimtab do much good? Would it be worth the extra work? Not to complex, but still extra work.

Best Regards
Robin Larsson