Bunker quantity disputes: how to check what was really delivered

Atlas Claims InsightsPublished 27 October 2026 · 8 min read

Bunkers are usually the largest single running cost of a voyage. A shortfall of one or two per cent on a large stem can be worth tens of thousands of dollars, and if it happens repeatedly the losses become significant. Yet many quantity claims fail, not because the shortfall was not real, but because the evidence was not collected in time or the notice requirements in the supplier’s terms were missed.

How bunker quantity is measured

The bunker delivery note (BDN) states the quantity delivered, normally in metric tons in air. That figure is derived from a volume measurement, either from the barge’s tanks before and after delivery or from a meter, converted to mass using:

• The observed volume at the temperature of the fuel when measured.
• A volume correction factor (VCF) from ASTM Table 54B, which converts the volume to its equivalent at 15 °C, based on the density and temperature.
• The density at 15 °C, less 1.1 kg/m³ to give the weight in air.

Each element can be wrong, by accident or otherwise. Our bunker quantity calculator runs the same conversion tank by tank and compares the result with the BDN.

Common causes of short delivery

• Entrained air (the “cappuccino effect”): air blown into the fuel makes it foam, so the barge tanks appear fuller at the opening gauge than they really are. Signs include foam on sounding tapes, bubbles in samples, gurgling in lines and levels that keep falling after delivery.
• Wrong temperatures: on the barge, an opening temperature recorded lower than the actual temperature, or a closing temperature recorded higher, overstates the quantity delivered. Temperatures wrongly recorded on the vessel distort the vessel’s own figure, so check both sides.
• Wrong density: if the BDN states a higher density than the fuel actually has, the mass will be overstated. A laboratory analysis of the representative sample is the best check.
• Hidden quantities: fuel left in barge pipelines, unreported tanks or bypassed meters.
• Measurement errors: trim and list not corrected, wrong calibration tables or careless gauging on either side.

Mass flow meters

Mass flow meters measure the mass of fuel delivered directly and reduce the room for manipulation. Singapore has required them for bunker deliveries by licensed suppliers since 2017, and other ports have followed, with ISO 22192 setting out procedures for metered deliveries. Meters are not infallible: check the meter seals and certificates, ask for the printed meter ticket and compare it with the vessel’s own figures. A meter reading that looks too good to be true often is.

What to do at the time of delivery

• Gauge both sides: take opening and closing soundings and temperatures on the barge and on the vessel, ideally witnessed by both parties or an independent surveyor.
• Check for foam and air: watch for signs of entrained air during and after pumping, and re-sound the vessel’s tanks once the fuel has settled.
• Sample properly: take continuous drip samples at the vessel’s manifold, sealed and signed by both sides, including the MARPOL sample, which must be retained on board for the authorities and should not be used for commercial testing.
• Protest promptly: if the figures do not match, issue a letter of protest before the barge leaves and note the dispute on the BDN. Do not sign a BDN without qualification for a quantity you have not verified.
• Keep everything: sounding records, temperature readings, trim and list, photographs, meter tickets, the timeline and all messages.

Building the claim

A persuasive quantity claim sets out the calculation clearly and shows why the vessel’s figures, or the survey, are more reliable than the supplier’s. It usually includes:

• The BDN figure and the measured figure, with the calculation tank by tank.
• The density used and the laboratory report that supports it.
• The vessel experience factor, if available, to show that the vessel’s measurements are reliable.
• The surveyor’s report, the letter of protest and the supplier’s response.
• The value of the shortfall at the contract price, plus any surveying costs.

Where the fuel was bought through a trader or broker, check who the contracting supplier is and whose terms apply. The physical supplier, the contractual seller and the party that issued the BDN may all be different.

Time limits and contract terms

Bunker supply terms, whether the supplier’s own or standard terms such as BIMCO’s Bunker Terms, usually impose strict conditions on quantity claims. Some require complaints to be recorded at the time of delivery; others allow only a few days. Many also limit the supplier’s liability and set out how disputes must be resolved. Read the terms before the stem, not after the problem appears, and diarise every deadline. If the charter makes charterers responsible for supplying bunkers, owners and charterers should agree early who will pursue the supplier.

This guide is general information about the law of England and Wales as at October 2026. It is not legal advice and may not cover your situation. Atlas Claims is not a law firm; for advice on your legal rights or on litigation, consult a qualified solicitor.