I'd be interested if anyone has actually tested the need for the kevlar. An airplane is built with no diagonals, the skin provides all that is needed. The Dacron is shrunk, then varnished. There is a lot of Dacron there to resist any torsional movement. Another test would be to lay the Dacron on the diagonal, since the stringers and ribs provide stiffness in the straight directions already. When you consider the area of Dacron, it has tremendous load capacity in tension. The question would be, would it stretch enough to put enough load on those joints for them to break. My guess would be no. If it were my boat, I would have done the tests long before this point.

Al

: Traditional SOF boats were built to flex gracefully. If a boat is going to
: flex it needs to be built to handle it. Since your boat uses glued joints,
: if it were to flex you would start breaking your joints. I would use the
: Kevlar to limit the flexing to minimum. Even though the boat may feel
: quite rigid now, it probably has some motion. Try twisting it. The Kevlar
: will tie everything together and distribute the loads more evenly though
: out the boat. The skin will do this to some extent, but not as effectively
: as the roving. Besides, the roving looks cool.