I've built and installed a rudder for a small (8') sailboat. It's just a piece of plywood on a hinge. Trying to modify a paddling rudder sounds like avoiding the easy to get a grip on the difficult. CLC didn't go thru' the trouble of designing that rudder for the hell of it. It's necessary. Build it. It will get you on the water sooner and while you are coming to grips with your new boat you can mull over modifying it to kick up. It's not hard. There are sailboat plans for free on the net that show the components for a kick-up rudder.
If you ruin that paddling rudder it will cost you ten times more to replace than building half a dozen plywood rudders.

: I'm currently in the throes of building a CLCSailRig for a CLC Triple. I'm up
: to the point of installling a rudder and therein lies the rub. The plans
: call for simple large rudder and the large size is apparently needed for
: efficient sailing. As far as I can tell, no commercially available rudders
: are large enough. The rudder in the plan doesn't have any nice features
: like kick-up or return, like on a commercially available rudder, and I'm
: not keen on doing the R&D to add these features. So here's what I was
: thinking. What if I take a rudder like a Feathercraft K2 and add a
: removable wooden "sleeve" over the blade large enough to provide
: the required surface area. This arrangement will also allow me to have a
: normal size rudder when not in sailing mode.The only reasons I can think
: of for not doing this is that this might overstress the parts on the
: rudder, specifically the pin used to attach the rudder to the boat. Also,
: the Frankenrudder might not be stiff enough. Unfortunately, I'm not an
: naval architect ( I don't even play one on TV) so I don't know how to
: evaluate the forces. There are probably other pitfalls I'm overlooking.

: Has anyone ever tried anything like this?