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Glossary · Bunkers & fuel compliance

Bunkers

The fuel a ship burns in her engines and boilers — residual and distillate marine fuels specified to ISO 8217 — and, as a verb, the act of supplying it.

Term

BUNKERSALSO: BUNKER FUEL · MARINE FUEL · BUNKERING · BUNKER STEMTOPIC: BUNKERS & FUEL COMPLIANCESOURCES: 3

Reviewed 2026-10-10

Definition

The word comes from the coal bunkers of steamships; today bunkers are liquid fuels (and increasingly LNG, methanol and biofuel blends). Their quality is specified by ISO 8217. Its 2024 edition, the seventh, replaced the 2017 edition and adds new residual grades that cover 0.50% sulphur VLSFOs, plus five RF grades for fuels blended with bio-components.[1]

Two families matter on an order: distillates (DM grades such as DMA, sold as marine gas oil) and residual fuels (RM grades, from heavy fuel oil to VLSFO). What a ship may burn is set by MARPOL Annex VI — 0.50% sulphur worldwide since 1 January 2020 and 0.10% inside emission control areas, unless she has an approved scrubber.[1,2]

A bunker order ("stem") states the grade and ISO 8217 edition, quantity, port and delivery method (barge or truck), the delivery window, and price basis. Every delivery leaves a bunker delivery note and a sealed sample; check the density and quantity on the note against your own soundings before you sign.[3]

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Sources

  1. [1] IBIA — ISO 8217:2024 marine fuel specification released — https://ibia.net/iso-82172024-marine-fuel-specification-released/
  2. [2] IMO — IMO 2020: cutting sulphur oxide emissions — https://www.imo.org/en/MediaCentre/HotTopics/Pages/Sulphur-2020.aspx
  3. [3] Lloyd’s Register — Class News 02/24: bunker delivery notes — https://www.lr.org/en/knowledge/class-news/02-24/

A working definition for buyers, not legal advice — the contract, the convention text and your club or class have the last word.

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