A diesel leak occurred to sea whilst fuel was being bunkered from a supply vessel to a Northern North Sea oil and gas production facility. The leak was detected during ongoing monitoring and the operation was immediately ceased to limit the leak. The leak was due to failure of the bunkering hose in the local vicinity of the connection to the manifold on the installation. The specification of the hose includes for a break away and sealing coupling, which is designed to be a “weak link” to prevent hose damage should a hose experience excess forces. Investigations showed the coupling operated correctly. Further investigations by the bunkering hose supplier have since indicated that when such hoses are subjected to angled pulls at an end fitting, the hose fails at a significantly lower load when compared to a straight pull along its axis. This could lead to premature failure.
Bunkering hoses have weakness at the portion nearest to the connection to installation manifolds when pulled at an angle. Angled pulls on bunkering hoses should be avoided by following good practices in bunkering.
Operators should consider the use of more robust hoses in the vicinity of their most vulnerable point, the connection to the manifold. Possibly graduated hoses where the highest strength is offered at the manifold connection section should be considered. Personnel handling bunkering hoses should be familiar with the Step Change in Safety publication Bulk Hose Best Practice Guidelines, which highlight the basic issues supporting these detailed recommendations. See Bulk Hose Best Practice Guidelines: