The Republic of Congo-controlled cargo ship from which six seafarers were abducted on Friday had also suffered a similar attack six years previously.
The 1,300-dwt Oya 1 (built 1986) has been identified by EOS Risk Group as the vessel boarded by a criminal gang on 30 June at the anchorage off Douala in Cameroon.
The vessel is owned by Ocean Express of Pointe Noire, which has been contacted for comment
The ship was also targeted by pirates in August 2017.
The Oya 1 was off Nigeria at that time.
Five crew members were abducted after the ship had left Takoradi in Ghana for Bonny.
Two officers, Ahmed Janani and Abdelkader Benhala, were among those taken.
The Panama-flag Oya 1 had arrived from Luanda in Angola before the latest attack.
The last AIS update shows it heading to Douala on 29 June.
The ship was about one nautical mile (1.8 km) off the port when it was boarded, and had been anchored there since the previous day.
Cameroon military attended scene
The vessel had a 1.84-metre freeboard at the time of the incident, security company Ambrey said.
Ambrey observed two Cameroonian military vessels responding to the incident, arriving at the scene within minutes. They left a little over an hour later.
Three days before the kidnapping, shipowners were alerted to an increased threat of pirate attacks off West Africa.
Ambrey said it had corroborated a message sent between the navies operating in the Gulf of Guinea.
In it, the navies assessed there was a credible threat and risk to merchant vessels, especially those transiting waters off Nigeria, Cameroon and Equatorial Guinea.
The previous week, a number of seafarers were injured when the 63,000-dwt Suisse-Atlantique bulker Nyon (built 2021) was boarded off Conakry in Guinea.
Security companies reported that crew members were attacked during the 30-minute raid on a Marshall Islands-flag vessel 33 km (21 miles) south-west of the port.
Four criminals boarded the ship with bladed weapons and used force to take money from the safe before fleeing.
