Eli5: Why do ships leave calm paths in the ocean?


As the title says, when a ship goes by it seems to leave a trail of calmer water, why is this?

In: Physics

Calm? At night, a ship’s wake glows in the dark because it’s stirring up luminescent algae. What do you mean by calm?


Waves are water that’s travelling on top of the rest of the water. They don’t just form, they are created by something pushing the water (usually wind). So when a ship goes through water, it pushes the waves to the side (due to the shape of the hull being designed to cut through the water) or just flattens the water, leaving a calmer patch behind it.

Unless there is really strong wind, once a ship has travelled over a section of water, it’ll remain flat until either wind creates new waves or waves from outside the calm zone move into it, which usually takes a while as the wake from the ship (the turbulent water) acts as a barrier.