: While not coating the frame may work just fine in the artic, most of us don't
: live there. The wood's gonna rot eventually if it's not protected in some
: way, specially where the skin wraps around the frame and holds moisture in
: contact with the wood and prevents quick drying.

That depends on where you paddle. While fresh water will definitely cause rot, salt water is actually a very good wood preservative. That's one reason you should not rinse out a boat with fresh water after paddling on the ocean.

: Personally I'd at least oil the wood, that's fast and doesn't add much
: weight.

True, but you must use tung oil (the pure stuff), NOT linseed oil, as mold and mildew feed on linseed oil. Varnishing the frame is a bad idea, since the finish will eventually crack, water will get under it and become trapped, and rot will form.