Tools for evaluation quay toe scouring induced by vessel propellers in harbour basins during the docking and undocking manoeuvring

Abstract

The evolution of the shipping industry (increased capacity and size of ships, power and self-propulsion), the increased productivity and rearrangement of spaces (port calls increased in number and frequency, changes in use of docks), the intensification of the use not only of stern main propellers (conventional or azimuthal) but also lateral bow and stern ones, are the leading causes of injury to the toe of the docks. Scouring processes due to manoeuvring actions can produce big consequences on the stability of harbour structures such as docks and protecting dikes. As a consequence, the sedimentation of the eroded sediment reduces the total depth of the harbour basin and navigation channel. At the same time, contaminants settled at the bed of the harbour basins may be resuspended by the effect of vessel’s propellers and produce an important environmental problem to harbour authorities. One of the main problems is the interpretation of parameters related to propellers, but also the fact of not considering important aspects such as different types of propeller, manoeuvring practices for docking and undocking, propulsion system orientation or the confinement effect generated by the dock itself and the shelter of the vessel. This contribution aims to assess docking and undocking manoeuvres which can produce erosion generated by the propulsion of ships. This methodology will analyse manoeuvres patterns and will allow understanding the effects of the sedimentation of the eroded sediment on docking and undocking manoeuvres.