Pollution Risk from Overboard Pipes Routed Through Fuel Oil Tanks
The West of England previously advised Members of a pollution incident involving the failure of a deck scupper drain pipe routed through a fuel oil tank. During bunkering, fuel entered the damaged pipe and escaped overboard through an undetected defect once the fuel level reached the height of the crack. There have been two more ...
The West of England has identified a pollution risk associated with overboard piping systems routed through fuel oil tanks aboard ships. In three separate incidents, fuel oil escaped into the sea through damaged sections of piping that ran through bunker or cargo tanks.
During bunkering operations, fuel oil entered a compromised section of piping routed through a fuel tank, and escaped overboard once the tank reached a certain level. Another incident involved a failed overboard discharge pipe within a bunker tank, with fuel oil escaping into the sea despite the overboard valve being closed. The final case saw a cracked welded seam in a pipe running from the ship's original construction, allowing oil to escape directly overboard.
The recurrence of these incidents across different vessel types underscores a broader risk. Even when seemingly isolated, overboard piping can provide a direct pathway for oil to escape into the sea if the pipe fails. The incidents reveal that closing the overboard valve does not prevent pollution if the pipe remains intact.
To mitigate this risk, the West of England advises ship managers and owners to review their overboard piping arrangements, particularly those that pass through bunker or cargo tanks. They should inspect the complete length of such pipes, including welded seams, joints, and areas prone to corrosion or vibration. Existing isolation measures may not be sufficient if the pipe extends beyond the isolation point to the ship's shell.
Members are encouraged to consider alternative routing for overboard piping, using non-oil compartments wherever possible. Retrofit modifications may be necessary for existing vessels, while newbuildings should be designed with this risk in mind. Any identified defects should be promptly reported to the vessel's Classification Society, which can oversee repairs and modifications. Interim controls, such as limiting tank filling levels, may also be considered to reduce pollution risk.
Written by urgent.news from Hellenic Shipping News's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.