Shortly after 2am three perpetrators boarded the 179,227-dwt Densa Shark (built 2012) armed with knives.
They were sighted in the engine room but left the Marinsa Denizcilik-owned bulker without taking anything.
Two and a half hours later, a group of five entered the engine room of the 84,000-cbm Clipper Posh (built 2013) but nothing was missing after they left.
Edvin Endresen, chief executive of Solvang which owns the vessel, confirms the incident to TradeWinds and says the ship is now preparing to depart after a comprehensive search was conducted.