- BDN
- Bunker Delivery Note — the document recording the quantity and characteristics of fuel delivered to a vessel.
- Bunkering
- The supply of fuel to a ship, whether by barge, truck or pipeline at berth or at anchorage.
- Cat fines
- Catalyst fines, abrasive particles carried over from refining that can cause engine wear if not removed by purification.
- Cutter stock
- A lighter component blended into residual fuel to bring viscosity and other parameters within specification.
- ECA
- Emission Control Area — a designated sea area with stricter sulphur or nitrogen oxide limits.
- HSFO
- High sulphur fuel oil, typically around 3.5% sulphur, used mainly by scrubber-fitted vessels.
- ISO 8217
- The international standard defining marine fuel specifications and test parameters.
- MGO
- Marine gasoil — a distillate marine fuel used where residual grades are unsuitable or unavailable.
- Off-spec
- Fuel that fails to meet the agreed specification on one or more parameters.
- Scrubber
- An exhaust gas cleaning system that allows a vessel to burn higher sulphur fuel while meeting emission limits.
- Stem
- A confirmed bunker order: the quantity, grade, port and delivery window agreed with a supplier.
- ULSFO
- Ultra low sulphur fuel oil at 0.10% sulphur, used inside emission control areas.
- VLSFO
- Very low sulphur fuel oil capped at 0.50% sulphur, the standard marine fuel for non-scrubber vessels.
- Viscosity
- A fuel's resistance to flow, which determines heating and handling requirements on board.
For how fuel costs feed into voyage economics, see the freight rates guide, or follow our bunkers and marine fuel coverage.