Bunkering is the process of supplying fuel oil (“bunkers”) to a vessel, typically delivered by a bunker barge alongside or occasionally from a shore pipeline connection.
Key Safety Considerations
- Fire and explosion risk — fuel transfer is inherently hazardous, requiring no-smoking zones, proper earthing/bonding between vessel and supplier, and readiness of firefighting equipment throughout
- Spill prevention — scuppers plugged, drip trays in place, and emergency shutdown procedures understood by all involved before transfer begins
- Continuous monitoring — tank levels and transfer rate are monitored throughout to prevent overflow, with the transfer rate reduced as tanks approach capacity
Quantity Verification
Bunker quantity is commercially significant — vessels typically verify delivered quantity through tank soundings/ullages before and after transfer, and increasingly through mass flow meters, to confirm the amount actually received matches what was ordered and paid for. Bunker quantity disputes are a real, recurring commercial issue in shipping.
Fuel Quality Sampling
Representative fuel samples are taken during bunkering (following MARPOL requirements) and retained, allowing quality disputes or off-specification fuel issues to be investigated after the fact if engine problems arise.
MARPOL Annex VI Compliance
Bunker fuel sulphur content must comply with MARPOL Annex VI limits for the vessel’s operating area, verified through the Bunker Delivery Note and fuel sampling — a compliance requirement with real regulatory consequences if violated.
Exam Relevance
Bunkering procedures, safety precautions, and quantity/quality verification are core Ship Knowledge topics in both deck and engine officer competency exams.