The estimates of wave-induced dynamic pressures around surface piercing twin-tandem rigid vertical circular cylinders fixed at the bottom of a wave flume, obtained using the source distribution method, are compared with the measured values. The influence of flume confinement on dynamic pressures is estimated by the method of images. The experiments are carried out on cylinders of 40 cm diameter mostly in deep water conditions in a wave flume 4 m wide, for different values of scattering parameters and spacings between the cylinders. © 1993.