Bunker
Bunker is the term for the fuel oil consumed by a ship's main engines and auxiliary generators. The act of refuelling a ship is called bunkering. Major bunker grades include HFO (Heavy Fuel Oil), MGO (Marine Gas Oil), VLSFO (Very Low Sulphur Fuel Oil — IMO 2020 compliant), and LNG/methanol for newer dual-fuel vessels.
Bunker procurement is one of the largest operational costs for shipping (often 50%+ of voyage cost). Bunker management workflows include: requirement forecasting per voyage, multi-port RFQ, price hedging, surveyor-witnessed delivery, stem reconciliation against quoted quantity, and IMO 2020 sulphur compliance evidence.
Bunkers are usually the single biggest voyage cost — often more than half. Small differences in grade, price and delivered-quantity reconciliation move real money, and IMO 2020 added a hard sulphur-compliance requirement on top. It is why bunker procurement, hedging and stem reconciliation get so much attention.
(IMO 2020)
What is VLSFO?
Very Low Sulphur Fuel Oil — a blended fuel at or below 0.5% sulphur, introduced to meet the IMO 2020 global sulphur cap without needing a scrubber.
Who pays for bunkers under a time charter?
The charterer. Under a time charter the charterer pays for fuel and port charges while the owner supplies the crewed, maintained vessel.