Guards and crew on a chemical tanker have thwarted Nigerian pirates that tried to board the vessel.
The attack took place on the unnamed ship 44 miles south-west of Bayelsa on 16 September, the IMB said.
While en route from Port Harcourt to Lagos, the vessel was approached by 12 armed men.
One boarded the tanker and attached two ladders for the other gunmen.
But the alarm was raised and all non-essential crew retreated to a safe room.
The master asked naval guards on board to fire warning shots as the pirates tried to move alongside.
The gunmen returned fire and a 30-minute battle ensued before the attackers moved away.
The superstructure and deck of the vessel sustained some damage due to the firing, but no injuries were reported.
