The image in that video is deceptive and you can see how in the following image. Showing an image is easier than explaining how half the boat in the video is actually a mirrored reflection.

Showing an unrelated image of a different ship with different atmospheric conditions does nothing to explain the video I linked.
If you watch the video I linked you can clearly see that the atmospheric conditions are such that no mirroring of the ship is evident where the ship and the water meet, so the bottom of the ship is not obscured by a mirror image of the top part of the ship, rather the bottom of the ship is obscured by water.