On the potential vulnerabilities and limitations of mass flow meters (MFMs) in bunkering operations, providing key tips for operators to avoid any complications.
Although the mass flow meters are designed to improve accuracy and reduce disputes, they are not immune to manipulation. Documented cases in Singapore showed the use of strong magnets placed on sensors to distort readings, resulting in inflated recorded deliveries and significant financial fraud. Other schemes have involved concealed or irregular piping arrangements allowing fuel to be diverted during transfer while still registering full volumes on the meter.
In addition, mass flow meters can be less reliable when operating outside calibrated flow ranges, particularly during low-flow “stripping” operations, which can further complicate accurate measurement and dispute resolution.
Despite the increased use of MFMs and the introduction of mandates in some ports, the crew of the receiving vessel should remain aware of how these systems can be manipulated and take measures to protect their position.
Key tips for operators
- Always take ship’s bunker tank soundings and witness barge measurements before and after bunkering, even where MFM figures are contractually binding, and retain records.
- Inspect visible sections of MFM systems, including seals (noting that there will likely be more than one), cabling, and piping arrangements where access is permitted.
- Request to see the MFM bunker system certificate and confirm the unit’s serial number.
- Engage reputable, experienced bunker surveyors, particularly in high‑risk ports or where past discrepancies have occurred.
- Issue letters of protest promptly where discrepancies arise between ship calculations and MFM figures, even if suppliers refuse to countersign.
- Ensure crews are familiar with bunkering procedures and aware of common manipulation indicators.
The crew should be aware of the limitations in accuracy when comparing tank measurements with MFM readings. Even when both measurement technologies are accurate, differences can still exist between them.