[sebaugh]

The keel stringer supplies longitudinal stiffness to the hull. It is often utilized as a connecting point in larger boats as they are often made in 2 halves and bonded together - the keel stringer adds another bonding point. As stated in an eariler reply, the wood does not supply the stiffness - it is the geometry. The taller the stringer the stiffer the the boat. Often they are hollow. The wood was a simple way to preform the glass materials. The only place stiff materials are required is on the top (stringer cap).