The Skagen Maersk is 1,138.5 feet long, and weighs over 100,000 tons. That sounds pretty big and strong. But when faced with some big waves, the whole thing undulates and groans like a bucking bronco. This is crazy.
We've seen videos of big ocean swells before, but we haven't seen just what it can do to the innards of a huge, ocean-going vessel. The power of the sea puts massive forces on the ship, forcing it to bend to its will. Even deep in the belly of the ship, you can see one end of a corridor swaying back and forth.
If I was on board, I'd probably jump off as soon as I could, because That Does Not Look Right.
But everything is all right, according to the video, and big ships are designed to twist about in heavy seas, much like airplane wings bend in turbulence. If they weren't flexible, they would break.
That doesn't make it feel any better though. I'd be putting on my lifejacket.