Anchorage

An anchorage is a place where ships lie at anchor rather than alongside a berth. Anchorages are commonly designated by the port or coastal authority and shown on charts, laid out so that vessels can hold position safely and clear of channels, other traffic and hazards. Ships use them for many reasons: waiting for a berth to become free, awaiting cargo instructions or documentation, waiting for a suitable tide to enter port, taking on bunkers or stores from a barge, undergoing inspection or crew changes, or simply sheltering from bad weather. A busy port may have several anchorages, sometimes designated for particular purposes such as quarantine, dangerous cargo or deep-draught ships.

What makes a good anchorage is a combination of factors the mariner assesses. There should be adequate but not excessive depth, so the anchor and an appropriate scope of cable can be used effectively. The holding ground (the nature of the seabed) matters greatly, since mud and clay generally hold an anchor well while rock, shingle or hard sand hold poorly and a ship is more likely to drag. Shelter from prevailing wind and swell improves safety and comfort, and there must be enough room for the ship to swing in a full circle around its anchor as the wind and tidal stream change direction without coming into danger or striking another vessel.

Lying at anchor is not a passive state. A ship keeps an anchor watch, monitoring its position by visual bearings, radar and GPS to detect any dragging of the anchor, and stands ready to act (veering more cable, using the engines, or weighing anchor and moving to a safer position) if the weather worsens or the anchor loses its grip. In congested anchorages the risk of collision with other anchored or manoeuvring ships is a constant concern. Anchorages are therefore an essential part of port operations and coastal navigation, and using them safely is a core seamanship skill.