200 years ago, every uneducated seaman knew about this. It's how large sailing ships would maneuver at anchor in a tideway in the days before the steam engine.,(reply>), Yes, and even with wind we often need to take into water currents and their effect on our course. Sailing is about balancing between the two and understanding fluid dynamics whether that fluid is air or water.,(reply>), I mean sailing ships would use the tide and anchors to maneuver exactly like this even when there was no wind.,(reply>), well, yeah, a sailing ship is using the same principles with the air currents that we call wind rather than water currents. Tidal currents also need to be accounted for.