Bunker fuel quality disputes
How an off-specification bunker claim is run: the retained sample, ISO 4259 test precision, the letter of protest, the supply contract time bar and the arbitration route.
A bunker fuel quality dispute arises when a delivered stem fails to meet the specification the buyer ordered, and it is decided far more often on evidence and procedure than on chemistry. The controlling questions are which sample is the contractual sample, whether the test result falls outside the specification once ISO 4259 precision is applied, and whether the buyer protested and claimed within the time limits the supply terms impose.
The full article will set out the evidential chain: the continuous drip sample drawn during transfer, the samples retained by supplier and receiver, the MARPOL sample retained under Annex VI Regulation 18, the chain of custody, and what a laboratory result does and does not prove. It will explain why a single result marginally outside a limit frequently fails as a claim, because ISO 4259 reproducibility means two laboratories testing the same fuel are expected to differ by a stated amount.
The article will then cover the remedies and their limits: the letter of protest, debunkering and its practical impossibility on a laden ship, the measure of damages where the fuel is consumed, the short time bars in standard supply terms such as the BIMCO Bunker Terms, and the interaction with the charter party where the charterer supplied the bunkers. It links to marine gas oil and ISO 8217:2024 .