Samenvatting

For the Dutch economy the ports of Amsterdam and Rotterdam are crucial. To continue the competitive positions of both ports versus foreign ports, the entrance channels to both ports have to be optimal. That said, it is however a problem. The largest ships calling at these ports have a very deep draught, so the ports are no longer accessible around the clock. Still to receive such vessels, the competent authority worked with a so called tidal window. This means the ship steams at a certain time before the high tide (highest water level) and must have reached the port a certaine lapsed time after the high tide. In other words there is an admission policy for the largest ships.This has to do with the water depth of the fairway and the draught of the ship. This article discusses the draught of the ship. A ship sailing in waves has no constant draught but a varying draught due the shipmotions, caused by the waves. These ship motions are: roll (rotation around the longitudinal axis), pitch (rotation around the lateral axis) and heave (translation in the direction of the vertical axis).