Marine Bunker Survey: Procedure and Reporting

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A marine bunker survey determines the quantity of fuel on board a vessel at a particular time. The results are recorded in a survey report, typically covering fuel oil (FO), diesel oil (DO) and lubricating oil (LO) where included in the agreed scope.

1. Equipment and documents to prepare

• A notebook, a suitable tank sounding tape and thermometer.
• An oil hydrometer with a suitable measurement range, together with oil-finding and water-finding pastes.
• The vessel's tank capacity tables and trim/list correction tables, plus the applicable petroleum correction tables; the example in this article refers to ASTM Tables 54B and 56.
• Safety goggles, gloves and a torch suitable for the working conditions.
• Sampling equipment and sample bottles or containers where sampling is required.

2. Check the information for each tank

Record the tank identification, depth, reference height and specified measurement method. Sounding measures the liquid height from the tank bottom to its surface; ullage measures the empty distance from the upper reference point to the liquid surface. Select the method according to the tank design and approved capacity tables, then apply the relevant corrections.

Cross-check the most recent bunker delivery report, the time and place of supply, the fuel density and the arrival fuel quantity recorded in the engine logbook. Check the sounding tape's accuracy before use, including when using the vessel's own tape.

3. Measure fuel levels and the vessel's condition

Measure and record the fuel level in each tank. Oil-finding paste can make the oil mark easier to identify on the tape where suitable for the fuel. Read the vessel's drafts to establish trim, check its list and use the vessel's correction tables when determining tank volume.

4. Determine temperature and density

Take samples and measure temperature and density in tanks that can be accessed appropriately. For heated service or settling tanks, follow the vessel's safety procedures; record temperatures from the tank's measuring equipment and cross-check the documented density data when direct sampling is not possible.

When old and new fuel of different densities are mixed in one tank, the mixture density can be estimated from their volume proportions if all values refer to the same reference conditions:

Example from the original article: mixing 200 m³ of fuel with a density of 0.9870 t/m³ and 200 m³ with a density of 0.9720 t/m³ gives an estimated density of 0.9795 t/m³. This value is calculated from the input data and must be distinguished from a direct measurement.

5. Calculate the fuel quantity and prepare the report

Determine the observed volume from the corrected measurement and the tank capacity tables. Use temperature, density and the applicable tables to convert to standard volume, then calculate mass. VCF corrects volume to reference conditions; it is not simply a conversion from cubic metres to kilolitres, because 1 m³ equals 1 kL.

• Prepare a tank measurement sheet and calculate each type of fuel separately.
• Clearly state the temperature, density, data sources, correction factors and units.
• Summarise the results in the marine bunker survey report.

ITVC provides bunker surveys in Hai Phong, Ho Chi Minh City, Da Nang, Nghi Son, Vung Tau, Phu My and other locations by agreement.