Two kinds of dispute
Bunker disputes fall into two families: quantity — you received less than the delivery note says — and quality — the fuel is off-specification against ISO 8217 or the nomination. Both are resolved on evidence gathered at the moment of delivery, which is why preparation matters more than argument afterwards.
Quantity: where it goes wrong, and how to defend it
Quantity disputes usually trace to tank-gauging error, temperature and density correction, aerated or "cappuccino" bunkers, or meter calibration differences. The defences are well established: an independent bunker quantity survey, joint opening and closing gauging on both vessel and barge, and verification of the barge's meter calibration certificates. Mass flow meters reduce disputes materially — Singapore has mandated metered delivery for fuel oil since 2017 and for distillates since 2019 — but they do not remove the need for diligence.
Quality: the evidence chain that actually counts
For quality, the single most important point is which sample is authoritative. The representative sample is the one drawn by continuous drip at the receiving vessel's bunker manifold throughout the entire transfer, in line with MARPOL Annex VI Regulation 18 and the IMO sampling guidelines in MEPC.182(59). That manifold sample — jointly drawn, witnessed, sealed and labelled — is the legally recognised sample in a dispute, not the barge's tank sample. Send it to an ISO 17025-accredited laboratory, and remember that ISO 4259 governs how test precision and the 95% confidence interval are applied when results sit close to a limit.
The Bunker Delivery Note
The BDN records the product, quantity in mass, density, flash point and sulphur content. If something is wrong, sign "under protest" with specific written objections rather than refusing to sign — a refused signature usually creates more difficulty than a protested one. Note any discrepancy immediately and in writing. MARPOL requires the BDN to be retained on board for three years, and the sealed MARPOL sample retained until the fuel is substantially consumed.
The contractual backbone
None of the above operates in a vacuum. Standard bunker terms and the relevant charter-party clauses set the notice procedures and the time bars for claims — miss the time bar and even a strong technical case can fail. Know the deadlines before you bunker, not after.
The takeaway
Three pillars protect you: the manifold drip sample, an independent quantity survey, and a properly protested BDN. Get them right at the time of delivery, because none of them can be reconstructed afterwards.
Frequently Asked Questions
In a dispute, which sample counts - the barge sample or the manifold sample?
The sample drawn by continuous drip at the receiving vessel's manifold during the whole transfer, under MARPOL Annex VI and MEPC.182(59), is the legally recognised representative sample — not the barge tank sample.
Should I refuse to sign the BDN if the quantity looks short?
No. Sign under protest with specific written objections. A refused signature tends to create more complication than a clearly protested one, and the protest preserves your position.
Do mass flow meters eliminate quantity disputes?
They reduce them materially by recording delivered mass directly, which is why Singapore mandates them. They do not remove the need for joint gauging, calibration checks and proper documentation.
How long should I keep the sample and the BDN?
MARPOL requires the BDN to be retained on board for three years and the sealed representative sample kept until the fuel has been substantially consumed, and in any case not less than twelve months.