Why ships always dock upstream?

Bicycles have brakes, cars and trains also have brakes. Do ships have “brakes”?
If you go by ship, you will discover a very interesting phenomenon: every time the ship wants to dock, always take the bow to catch the water, slowly tilt to the dock, then calmly dock. The ships running downstream, when they arrive at the prescribed place, do not dock immediately but go around a wide circle first, causing the train to run upstream, then slowly dock.

There is a simple problem here; try it. Suppose the water flow rate is 3 km / h. When the ship was about to dock, the engine stopped, the speed of the train was 4 km / h. At that time, if it was downstream, how many kilometers could it travel every hour? What about upstream? You can tell the answer immediately. When downstream, every hour the train runs 7 km, while upstream, every hour the train runs 1 km. To stop the train, the train runs 7 km / h, and the train runs 1 km / h, which is easier to stop. Of course, the slower the train, the easier it is to stop.

We can see that for the ship to dock upstream, and it is possible to take advantage of the water’s resistance to the hull as part of the “brake” effect. Of course, there are also “braking” devices and dynamics installed on the ship; for example, when a ship is docked, or there is an emergency on the course of operation, it is necessary to stop, it can anchor. Simultaneously, the ship’s main engine can also take advantage of running back to cause the “braking” effect.