Bunker quantity calculator.

The observed volume in each tank is corrected to its volume at 15 °C by multiplying it by the volume correction factor (VCF) from ASTM Table 54B, which depends on the density at 15 °C and the observed temperature. The volume at 15 °C is then multiplied by the density at 15 °C less 1.1 kg/m³ to give metric tons in air, the basis normally used on bunker delivery notes.

The density at 15 °C stated on the bunker delivery note is the supplier’s figure. If a laboratory analysis of the representative sample shows a lower density, the delivered mass will be lower too, so using the tested density is often the key to a quantity claim. Keep the sealed samples and the analysis report.

A vessel experience factor (VEF) compares a ship’s historical tank measurements with shore or supplier figures. It reflects the ship’s own measurement tendencies. Dividing the vessel’s figure by its VEF gives a fairer comparison with the delivery note.

Small differences can come from measurement tolerances, trim and list, or temperature readings. Many surveyors treat differences within a few tenths of a per cent as normal. Larger shortfalls, or a pattern across deliveries, are worth investigating, especially where there is evidence of entrained air, unusual temperatures or meter irregularities.

Yes. For the delivering barge, the quantity delivered is the opening figure minus the closing figure. For the receiving vessel, it is the closing figure minus the opening figure. Choose the side that matches your soundings. If both were measured, compare the two results.

Have the soundings witnessed or surveyed, record temperatures and trim, take and seal samples at the manifold, and issue a letter of protest before the barge leaves if the figures do not match. Do not sign for a quantity you have not verified without noting your protest on the BDN.