Water transport in wake waves from high-speed vessels

A new mechanism producing onshore transport of substantial amounts of water remote from the fairway in wake waves generated by high-speed vessels is described based on high-resolution water surface profiling in Tallinn Bay, the Baltic Sea. In addition to water transported by precursor solitons, an elevation event that arrives in remote areas well after the precursors is able to carry several times as much water as the solitons and the other wave disturbances put together. When it arrives, just before the largest vessel waves, its interaction with the leading waves of wakes may produce water level set-up under groups of high ship waves. Its characteristic position at the study site, just before the highest wave group, suggests that it may be a forced disturbance created by the ship motion, the nature of which could be an almost degenerate undular bore. The backflow of this water potentially contributes to fast removal of sediment from non-equilibrium beaches by forming strong offshore-directed flow during the latter phase of the wake-wave event.

Research Highlights
► There is set-up of the water surface under groups of large vessel wake waves.
► We identify a previously unknown elevation event associated with vessel wakes.
► We describe a new mechanism of water transport in the wakes of high-speed vessels.
► A method for quantification water transport from surface profiling is developed.
► A mechanism exists for vessel wakes to cause the fast removal of beach sedimen.