When a current is crossed by a vessel on fixed course at fixed speed, the vessel is displaced downstream. The displacement, D, is proportional to the current speed integrated across the width of the current and is inversely proportional to the vessel's speed....
Montgomery, R. B.. 1968. "Oceanic leveling by a vessel crossing a current." Journal of Marine Research 26, (1). https://elischolar.library.yale.edu/journal_of_marine_research/1117