Vessel trans-critical wave wake, divergent wave angle and decay

Vessel wave wake in the "deep water" condition, or the sub-critical depth Froude number range, is well understood, trans-critical wave wake less so, despite vessels frequently operating within this region. The significant effect of water depth on catamaran wave wake and the fundamental changes in the wave pattern are presented. Specific attention is paid to wave height, bow wave angle and the rate of decay coefficient. From model test results a simple and novel method for the prediction of catamaran wave wake, across the trans-critical depth Froude range is presented. The experiments showed that the decay coefficient of the vessel generated waves varies with depth Froude number. Also that the maximum bow wave angle closely corresponds to that predicted by theory, however the peak value is found to occur closer to Fr, ~0.9 than 1.0.