What do you mean by anchorage movement?

The motion phenomenon of ships anchored in anchorage under the influence of wind and waves. Anchorage refers to the sea area for ships to berth, also known as anchorage. Anchorage is generally selected in the waters near the port, with good shelter from the wind, suitable sediment conditions and spacious waters, which will not affect the navigation or berthing of other ships. Motion refers to the phenomenon that a ship will move under the action of natural forces such as wind, waves and swells during anchoring.