Port & Terminal Operations
Maritime and shipping terms in the port & terminal operations category, clearly defined.
AIS
Automatic Identification System, a tracking system that uses VHF radio transponders on ships to automatically exchange vessel identification, position, course, speed, and other data with nearby ships and shore-based systems. AIS is mandatory for vessels of 300 gross tonnage and above on international voyages under SOLAS.
Abandon Ship
The order given by the master to evacuate a vessel when the ship is in imminent danger of sinking or when conditions aboard pose an immediate threat to life. Abandon ship drills are conducted regularly to ensure all crew members know their duties, muster stations, and how to operate lifesaving equipment.
Abeam
A direction at right angles (90 degrees) to the fore-and-aft centerline of a vessel. An object is said to be abeam when it is directly to the side of the ship, neither ahead nor astern.
Admiralty Law
The body of private international law governing maritime activities and disputes, including navigation, shipping, salvage, pollution, and seafarers' rights. Admiralty law, also called maritime law, is distinct from the law of the sea (UNCLOS), which governs relations between nations.
Aframax
A medium-sized tanker with a deadweight tonnage between 80,000 and 120,000 DWT, named after the Average Freight Rate Assessment (AFRA) system. Aframax vessels are versatile and can access a wide range of ports and terminals worldwide.
Anchor
A heavy device lowered to the seabed on a chain or cable to hold a vessel in position. Modern ships typically carry two bower anchors at the bow, sized according to the vessel's classification society rules based on equipment number.
Anchorage
A designated area of water near a port where vessels anchor while waiting for a berth, pilot, favourable tide, or customs clearance. Anchorage areas are selected for suitable seabed holding ground, adequate depth, and shelter from prevailing weather.
Arrest of Ship
A legal procedure in admiralty law by which a claimant detains a vessel to obtain security for a maritime claim. Ship arrest is a powerful remedy available to creditors and can be executed in the port where the vessel is found, regardless of the vessel's flag or the owner's nationality.
Astern
Behind the vessel, or moving in a backward direction. "Going astern" means the vessel is moving backward through the water, typically achieved by reversing the propeller.
Auxiliary Engine
A secondary diesel engine on board a vessel used primarily to drive electrical generators that supply power for the ship's hotel load, cargo-handling equipment, navigation systems, and other onboard services. Most vessels carry multiple auxiliary engines for redundancy and load management.
Ballast Tank
Tanks within a vessel's hull that can be filled with or emptied of seawater to adjust the vessel's trim, stability, and draft. Ballast water management is regulated internationally to prevent the transfer of invasive aquatic species between ecosystems.
Ballast Water Treatment
Systems installed on vessels to treat ballast water before it is discharged overboard, removing or neutralising harmful aquatic organisms and pathogens. The IMO Ballast Water Management Convention (BWM Convention) requires all ships to install approved treatment systems to prevent the transfer of invasive species.
Baltic Dry Index
A shipping and trade index created by the Baltic Exchange in London that measures the cost of transporting major raw materials by sea. The BDI is composed of assessments for Capesize, Panamax, and Supramax routes and is widely regarded as a leading indicator of global economic activity.
Bareboat Charter
A charter party agreement in which the shipowner provides only the vessel without crew, provisions, or insurance. The charterer assumes full operational control and responsibility for the vessel, effectively acting as the disponent owner for the duration of the charter.
Barecon
A standard bareboat charter party form published by BIMCO, widely used in the shipping industry for bareboat or demise charter agreements. Barecon sets out the terms under which a vessel is chartered without crew, provisions, or insurance, placing full operational responsibility on the charterer.
Beam
The width of a vessel at its widest point, measured at the midship section. Beam is a key dimension that affects stability, cargo capacity, and the ability to transit canals and locks.
Bearing
The horizontal direction of one point from another, measured clockwise from true north, magnetic north, or the heading of a vessel. Bearings are expressed in degrees from 000 to 360.
Beaufort Scale
A scale of wind force ranging from 0 (calm) to 12 (hurricane force) developed by Rear Admiral Sir Francis Beaufort in 1805. The scale relates wind speed to observed conditions at sea and on land, and remains the standard for reporting wind conditions in maritime weather forecasts.
Berth
A designated location in a port or harbour where a vessel is moored for loading, discharging, or other operations. Berths are equipped with mooring fixtures, fenders, and cargo-handling equipment appropriate to the type of vessels and cargo they serve.
Bilge
The lowest internal part of the hull where the sides curve inward to meet the bottom. The bilge collects water that enters the hull from leaks, condensation, or washing, and bilge pumps remove this water overboard through an oily-water separator.