Abstract: A computer-implemented method for identifying a potential ship-to-ship “STS” cargo transfer, the method comprising determining a distance between a first vessel and a second vessel, determining if the distance is below a vessel distance threshold, if the distance is below the vessel distance threshold, determining a period of the distance being below the vessel distance threshold, determining if the period is above a time threshold, and, if the period is above the time threshold, identifying a potential STS cargo transfer.