Twelve pirates armed with guns boarded the Liberian-flagged tanker Thursday off Togo's capital of Lome on Africa's west coast, said Noel Choong, head of the IMB's piracy reporting centre.
Keeping the crew under gun threat, they transferred the tanker's gas oil to their bunker barge and ransacked the ship. They later locked the crew in the master's cabin and stole their personal belongings before abandoning the ship.
There were no casualties among the 14 crew members, but a few of them had "light injuries", Choong said.
The number of attacks in the Gulf off Guinea now stands at 43 attacks this year and have been on the rise recently, Choong said.
Those include several hijackings, kidnappings and killings. Pirates usually target fuel cargo, loading it onto other ships to sell on the lucrative black market.
The Malaysia-based centre has repeatedly warned ships plying the area to be vigilant and called on authorities to step up patrols, last year saying the region was emerging as a new piracy "hot spot."
Piracy has long been a problem off Nigeria, Africa's largest oil producer and most populous nation, but it has now spread to neighbouring nations.