Bunker Disputes – The “Cappuccino Effect”

• If the air in the fuel oil is found or suspected, the vessel should endeavor to wait for the air to escape after bunkering has been completed. The length of time required will depend on the viscosity and temperature of the fuel oil, as well as the size of the entrapped bubbles. The process will be quicker in tropical waters, but very small air bubbles in high viscosity fuels in cold climates may take up to two days to dissipate before accurate soundings can be taken.
• The Chief Engineer should ask the Barge Master to advise when tank stripping will be carried out. Tank stripping should be kept to a minimum and the Chief Engineer should record how long it takes to strip the barge tanks.
• Line blowing by the barge should only be permitted on completion of bunkering.
• If the Chief Engineer believes that the vessel has been supplied with fuel into which air has been introduced, samples should be taken from the affected tanks and examined in a clean glass receptacle for the presence of air bubbles. The density of the samples should also be checked. If bubbles are present and the density (allowing for any temperature change) is lower than the figure declared on the Bunker Delivery Note, these may be indications of the “cappuccino effect”.
• Detailed records of times, soundings, quantities, temperatures, densities and other key information should be maintained in case they are needed in the event of a dispute. Where safe and practicable, photographic and video evidence should also be taken for the same reason.

Actions Following Signs of the “Cappuccino Effect”

Should a vessel suspect that it is receiving fuel oil containing air, the bunkering operation should be stopped immediately. An attempt should be made to identify and eliminate the

source of the air and a letter of protest should be presented to the Barge Master. Similarly, a letter of protest should be issued if evidence of the “cappuccino effect” is found on completion of bunkering. Owners and (where applicable) charterers should be informed without delay. The local P&I correspondent should also be contacted for advice who may appoint an independent bunker surveyor to assist the vessel. If a significant discrepancy is found between the quantity the barge claims to have delivered and the vessel’s own figures, another set of tank soundings should be taken and the calculations repeated with all parties in attendance. If this again results in a shortfall: