You can know the direction of travel by the direction of looking at the sun.
Also, at deep depths, it is difficult for the sunlight to reach and the brightness decreases.
●Sound
You can see the sound of the boat's screw and the sound of stones hitting each other by waves.
●Currents and tides
The shallower the water depth makes the stronger the water flow due to the waves.
If you swim against the current, you can return to the original position by swimming along the current.
However, since the direction and strength of the tidal current change with
time, the direction of the tidal current is opposite after the tidal current
stops. Pay attention to the tidal current
stops.
