Mariners consider anchoring a ship to be an art. In fact, it’s also a form of science for it involves a sense of pivot, around which, a ship turns and imparts the stalling force to the ship.
While berthing a ship alongside a jetty or a pier in tidal or windy conditions, the role of the ship’s anchor is extremely vital.
Preferably, a ship must always approach the berth or a jetty stemming the tide (reduce the effect of the tide by cutting it) to ensure better control of the vessel. If the opposite is done when the ship is berthed, i.e. if the ship approaches the berth or jetty with the tide at its stern, the rudder effect is minimized as the tide plays with the stern.
To turn the vessel, which is coming up the tidal estuary along with the tide, the anchor is dropped on the side towards which the vessel has to be turned. If the vessel is planned to turn on the starboard wheel, the starboard anchor is dropped. Likewise, if it’s planned to turn on the port wheel the port anchor is dropped.This is done to avoid the anchor chain going across the stern of the vessel after the swing.
But before dropping the anchor, the ship’s speed is reduced to around 3 knots or less to minimize the chances of chain damage or damage to the ship’s equipment and hull.