Patent ID: 7938705

Claim:
A waterboard having externally adjustable stiffness, comprising: a generally elongated foam core having a forward nose and a rearward tail and a longitudinally disposed channel, the channel having an approximately uniform cross-section, an opening at the tail and terminating within the foam core within a forward portion of the foam core; an adjustable flex stringer assembly disposed substantially within the channel, comprising: a housing having a cylindrical bore and an external cross-section configured to create a friction or interference fit with the channel, occupying a rearwards portion of the channel; a stringer comprising a cylindrical shank disposed within the cylindrical bore of the housing, and a beam element disposed within approximately a forward third of the channel; an end cap engaged with the cylindrical shank and configured to rotate the stringer under an application of torque, wherein a stiffness of the beam element in a direction normal to a surface of the waterboard is modulated between a minimum stiffness and a maximum stiffness.