Fig. 9. Tracings of the motion of models of each type in waves. Arrows indicate the distance the tip of the model moved from its upright position (dotted line) in one direction per wave (not to scale). a, very flexible, buoyant; b, flexible, buoyant; c, flexible, non-buoyant; d, stiff, extra-buoyant; e, stiff, buoyant; f, rigid buoyant.