These very long and regular wave crests were caused by a ship — they are one side of the V of a ship’s wake that’s about to reach the sea wall here.
I love how well defined the wave crests are — on one side you see the reflection of the bollards and the bright sky, on the other side the reflection of the dark sea wall.
Below you can see the waves approaching the sea wall and then their reflection:
And I realized that it’s a very good thing I didn’t own a smartphone when I was still working at GEOMAR, otherwise you’d be completely fed up by these kinds of pictures by now :-)
For the rest of this post: More pictures of more wakes as seen from the roof top terrace, which very nicely show you the V-shape…
I just love how you see the “feathers” that, together, make up the V-shaped wake.
And several wakes on top of each other…
And below you see the turbulent wake in the middle of the V as a lighter line where the surface appears smooth due to turbulence.