Reference
Maritime glossary
24 shipping terms, defined plainly — each linked to the tool or page where it matters.
TCE (Time Charter Equivalent)
A voyage's earnings expressed as a daily rate: net voyage result (freight minus voyage costs such as bunkers, port costs and commission) divided by total voyage days. The standard way to compare a spot voyage against a time-charter rate. TCE calculator →
Laytime
The time allowed under a charter party for loading and discharging cargo. Time used beyond laytime normally incurs demurrage; finishing early can earn despatch.
Demurrage
The daily charge payable by the charterer when a vessel is kept in port beyond the agreed laytime. Set by the charter party and often a five- or six-figure daily amount.
Despatch
A payment from owner to charterer for finishing cargo operations in less than the agreed laytime — commonly half the demurrage rate.
ECA (Emission Control Area)
A sea area designated under MARPOL Annex VI where stricter air-emission limits apply — principally a fuel sulphur cap of 0.10% m/m, versus 0.50% in open waters. In-force ECAs: Baltic, North Sea, North American, US Caribbean and Mediterranean. ECA checker →
SECA
Sulphur Emission Control Area — the earlier name for what MARPOL Annex VI now calls an Emission Control Area (ECA) for SOx and particulate matter.
NOx Tier III
The strictest NOx limit under MARPOL Annex VI, applying inside designated NOx ECAs to ships constructed on or after set dates (2016 in the North American ECA, 2021 in the North Sea and Baltic).
SOx
Sulphur oxides produced when fuel oil burns. Capped at 0.50% sulphur content globally since 2020 and 0.10% inside ECAs, unless an approved equivalent such as a scrubber is fitted.
Nautical mile (nm)
One minute of latitude — exactly 1,852 metres. The standard unit for sea distances and the basis of the knot. Unit converter →
Knot (kn)
One nautical mile per hour — about 1.852 km/h or 0.514 m/s. Vessel service speeds are normally quoted in knots.
Deadweight (DWT)
The total weight a ship can safely carry — cargo, bunkers, stores, crew and effects — measured in metric tonnes. Roughly, vessel size for cargo ships.
Ballast / ballast leg
Water carried for stability when a ship has little or no cargo; a ballast leg is a repositioning voyage without cargo, which earns no freight.
TEU
Twenty-foot Equivalent Unit — the standard container-capacity measure. One 40-foot container counts as 2 TEU (one FEU). Unit converter →
LOA (Length Overall)
The maximum length of a vessel's hull, bow to stern — a key constraint for berths, locks and canals.
Draft (draught)
The vertical distance between the waterline and the keel — the minimum water depth a vessel needs, and a critical port-entry constraint.
Charter party
The contract between shipowner and charterer covering the hire of a vessel — voyage, time or bareboat — including laytime, demurrage and freight terms.
Bill of lading (B/L)
The document issued for shipped goods that serves as receipt, contract of carriage evidence and document of title.
Bunker / bunkering
Marine fuel oil (VLSFO, MGO, HSFO) or the act of taking it aboard. Bunker cost is usually the largest single voyage cost. Bunker cost estimator →
VLSFO
Very Low Sulphur Fuel Oil — max 0.50% sulphur, the mainstream compliant fuel outside ECAs since the 2020 global cap.
Slow steaming
Running below design speed to cut fuel consumption — fuel burn rises roughly with the cube of speed, so small speed reductions save disproportionately.
JIT arrival (just-in-time)
Adjusting speed so a vessel reaches pilot station exactly when a berth is ready — cutting fuel burn and anchorage waiting instead of hurrying to wait.
Suez Canal
The sea-level canal linking the Mediterranean and Red Sea between Port Said and Suez — the shortest Asia–Europe route, saving roughly 3,500 nm against the Cape of Good Hope on a Rotterdam–Singapore voyage. Canal vs cape calculator →
Cape of Good Hope route
The open-sea route around southern Africa used when canals are avoided — adds distance and days but no canal tolls. Canal vs cape calculator →
Worldscale (WS)
The tanker industry schedule of nominal freight rates per tonne for standard routes; fixtures are quoted as a percentage of it (WS 100 = the nominal rate).
Get in touch
Put the terms to work.
Free calculators for distances, transit time, TCE, bunkers and canal economics.