: . . . "What
: are the stresses or loads on the masik that warrant a hardwood
: construction, when the rest of the frame is cedar?" I don't
: plan to sit or stand on it. It seems that it will primarily have
: to bear the force of bracing against it during paddling and
: rolling; it will be probably carry some of the weight of the
: boat when I'm carrying the boat on my shoulder; it will feel the
: pull of the skin wrapped around it; what else?

It will probably take your entire weight when you get into the boat.

It sits in the middle of the boat and needs to resist the folding action of the bow and stern sections, when they are in waves and the center of the boat is in a wave trough. That would be your weight in the middle multiplied by the factor of whatever leverage might be exerted. Some of these forces are shared by the sheer/gunwale. I'm not an engineer, so I'm not going to even try to do the math on that!

PGJ